建筑给排水_外文文献翻译1
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外文原文:Sealed building drainage and vent systems—an application of active air pressure transient control and suppression AbstractThe introduction of sealed building drainage and vent systems is considered a viable proposition for complex buildings due to the use of active pressure transient control and suppression in the form of air admittance valves and positive air pressure attenuators coupled with the interconnection of the network's vertical stacks.This paper presents a simulation based on a four-stack network that illustrates flow mechanisms within the pipework following both appliance discharge generated, and sewer imposed, transients. This simulation identifies the role of the active air pressure control devices in maintaining system pressures at levels that do not deplete trap seals.Further simulation exercises would be necessary to provide proof of concept, and it would be advantageous to parallel these with laboratory, and possibly site, trials for validation purposes. Despite this caution the initial results are highly encouraging and are sufficient to confirm the potential to provide definite benefits in terms of enhanced system security as well as increased reliability and reduced installation and material costs.Keywords: Active control; Trap retention; Transient propagationNomenclatureC+-——characteristic equationsc——wave speed, m/sD——branch or stack diameter, mf——friction factor, UK definition via Darcy Δh=4fLu2/2Dgg——acceleration due to gravity, m/s2K——loss coefficientL——pipe length, mp——air pressure, N/m2t——time, su——mean air velocity, m/sx——distance, mγ——ratio specific heatsΔh——head loss, mΔp——pressure difference, N/m2Δt——time step, sΔx——internodal length, mρ——density, kg/m3Article OutlineNomenclature1. Introduction—air pressure transient control and suppression2. Mathematical basis for the simulation of transient propagation in multi-stack building drainage networks3. Role of diversity in system operation4. Simulation of the operation of a multi-stack sealed building drainage and vent system5. Simulation sign conventions6. Water discharge to the network7. Surcharge at base of stack 18. Sewer imposed transients9. Trap seal oscillation and retention10. Conclusion—viability of a sealed building drainage and vent system1.Air pressure transients generated within building drainage and vent systems as a natural consequence of system operation may be responsible for trap seal depletion and cross contamination of habitable space [1]. Traditional modes of trap seal protection, based on the Victorian engineer's obsession with odour exclusion [2], [3] and [4], depend predominantly on passive solutions where reliance is placed on cross connections and vertical stacks vented to atmosphere [5] and [6]. This approach, while both proven and traditional, has inherent weaknesses, including the remoteness of the vent terminations [7], leading to delays in the arrival of relieving reflections, and the multiplicity of open roof level stack terminations inherent within complex buildings. The complexity of the vent system required also has significant cost and space implications [8].The development of air admittance valves (AAVs) over the past two decades provides the designer with a means of alleviating negative transients generated as random appliance discharges contribute to the time dependent water-flow conditions within the system. AAVs represent an active control solution as they respond directly to the local pressure conditions, opening as pressurefalls to allow a relief air inflow and hence limit the pressure excursions experienced by the appliance trap seal [9].However, AAVs do not address the problems of positive air pressure transient propagation within building drainage and vent systems as a result of intermittent closure of the free airpath through the network or the arrival of positive transients generated remotely within the sewer system, possibly by some surcharge event downstream—including heavy rainfall in combined sewer applications.The development of variable volume containment attenuators [10] that are designed to absorb airflow driven by positive air pressure transients completes the necessary device provision to allow active air pressure transient control and suppression to be introduced into the design of building drainage and vent systems, for both ‘standard’ buildings and those requiring particular attention to be paid to the security implications of multiple roof level open stack terminations. The positive air pressure attenuator (PAPA) consists of a variable volume bag that expands under the influence of a positive transient and therefore allows system airflows to attenuate gradually, therefore reducing the level of positive transients generated. Together with the use of AAVs the introduction of the PAPA device allows consideration of a fully sealed building drainage and vent system.Fig. 1 illustrates both AA V and PAPA devices, note that the waterless sheath trap acts as an AA V under negative line pressure.Fig. 1. Active air pressure transient suppression devices to control both positive and negative surges.Active air pressure transient suppression and control therefore allows for localized intervention to protect trap seals from both positive and negative pressure excursions. This hasdistinct advantages over the traditional passive approach. The time delay inherent in awaiting the return of a relieving reflection from a vent open to atmosphere is removed and the effect of the transient on all the other system traps passed during its propagation is avoided.2.Mathematical basis for the simulation of transient propagation in multi-stack building drainage networks.The propagation of air pressure transients within building drainage and vent systems belongs to a well understood family of unsteady flow conditions defined by the St Venant equations of continuity and momentum, and solvable via a finite difference scheme utilizing the method of characteristics technique. Air pressure transient generation and propagation within the system as a result of air entrainment by the falling annular water in the system vertical stacks and the reflection and transmission of these transients at the system boundaries, including open terminations, connections to the sewer, appliance trap seals and both AAV and PAPA active control devices, may be simulated with proven accuracy. The simulation [11] provides local air pressure, velocity and wave speed information throughout a network at time and distance intervals as short as 0.001 s and 300 mm. In addition, the simulation replicates local appliance trap seal oscillations and the operation of active control devices, thereby yielding data on network airflows and identifying system failures and consequences. While the simulation has been extensively validated [10], its use to independently confirm the mechanism of SARS virus spread within the Amoy Gardens outbreak in 2003 has provided further confidence in its predictions [12].Air pressure transient propagation depends upon the rate of change of the system conditions. Increasing annular downflow generates an enhanced entrained airflow and lowers the system pressure. Retarding the entrained airflow generates positive transients. External events may also propagate both positive and negative transients into the network.The annular water flow in the ‘wet’ stack entrains an airflow due to the condition of ‘no slip’ established between the annular water and air core surfaces and generates the expected pressure variation down a vertical stack. Pressure falls from atmospheric above the stack entry due to friction and the effects of drawing air through the water curtains formed at discharging branch junctions. In the lower wet stack the pressure recovers to above atmospheric due to the traction forces exerted on the airflow prior to falling across the water curtain at the stack base.The application of the method of characteristics to the modelling of unsteady flows was first recognized in the 1960s [13]. The relationships defined by Jack [14] allows the simulation to model the traction force exerted on the entrained air. Extensive experimental data allowed the definition of a ‘pseudo-friction factor’ applicable in the wet stack and operable across the water annular flow/entrained air core interface to allow combined discharge flows and their effect on airentrainment to be modelled.The propagation of air pressure transients in building drainage and vent systems is defined by the St Venant equations of continuity and momentum [9],(1)(2)These quasi-linear hyperbolic partial differential equations are amenable to finite difference solution once transformed via the Method of Characteristics into finite difference relationships, Eqs. (3)–(6), that link conditions at a node one time step in the future to current conditions at adjacent upstream and downstream nodes, Fig. 2.Fig.2. St Venant equations of continuity and momentum allow airflow velocity and wave speed to bepredicted on an x-t grid as shown. Note , .For the C+ characteristic:(3)when(4)and the C- characteristic:(5)when(6)where the wave speed c is given byc=(γp/ρ)0.5. (7) These equations involve the air mean flow velocity, u, and the local wave speed, c, due to the interdependence of air pressure and density. Local pressure is calculated as(8)Suitable equations link local pressure to airflow or to the interface oscillation of trap seals.The case of the appliance trap seal is of particular importance. The trap seal water column oscillates under the action of the applied pressure differential between the transients in the network and the room air pressure. The equation of motion for the U-bend trap seal water column may be written at any time as(9)It should be recognized that while the water column may rise on the appliance side, conversely on the system side it can never exceed a datum level drawn at the branch connection.In practical terms trap seals are set at 75 or 50 mm in the UK and other international standards dependent upon appliance type. Trap seal retention is therefore defined as a depth less than the initial value. Many standards, recognizing the transient nature of trap seal depletion and the opportunity that exists for re-charge on appliance discharge allow 25% depletion.The boundary equation may also be determined by local conditions: the AAV opening and subsequent loss coefficient depends on the local line pressure prediction.Empirical data identifies the AAV opening pressure, its loss coefficient during opening and at the fully open condition. Appliance trap seal oscillation is treated as a boundary condition dependent on local pressure. Deflection of the trap seal to allow an airpath to,or from, the appliance or displacement leading to oscillation alone may both be modelled. Reductions in trap seal water mass during the transient interaction must also be included.3. Role of diversity in system operationIn complex building drainage networks the operation of the system appliances to discharge water to the network, and hence provide the conditions necessary for air entrainment and pressure transient propagation, is entirely random. No two systems will be identical in terms of their usage at any time. This diversity of operation implies that inter-stack venting paths will be established if the individual stacks within a complex building network are themselves interconnected. It is proposed that this diversity is utilized to provide venting and to allow serious consideration to be given to sealed drainage systems.In order to fully implement a sealed building drainage and vent system it would be necessary for the negative transients to be alleviated by drawing air into the network from a secure space andnot from the external atmosphere. This may be achieved by the use of air admittance valves or at a predetermined location within the building, for example an accessible loft space.Similarly, it would be necessary to attenuate positive air pressure transients by means of PAPA devices. Initially it might be considered that this would be problematic as positive pressure could build within the PAPA installations and therefore negate their ability to absorb transient airflows. This may again be avoided by linking the vertical stacks in a complex building and utilizing the diversity of use inherent in building drainage systems as this will ensure that PAPA pressures are themselves alleviated by allowing trapped air to vent through the interconnected stacks to the sewer network.Diversity also protects the proposed sealed system from sewer driven overpressure and positive transients. A complex building will be interconnected to the main sewer network via a number of connecting smaller bore drains. Adverse pressure conditions will be distributed and the network interconnection will continue to provide venting routes.These concepts will be demonstrated by a multi-stack network.4. Simulation of the operation of a multi-stack sealed building drainage and vent systemFig. 3 illustrates a four-stack network. The four stacks are linked at high level by a manifold leading to a PAPA and AAV installation. Water downflows in any stack generate negative transients that deflate the PAPA and open the AAV to provide an airflow into the network and out to the sewer system. Positive pressure generated by either stack surcharge or sewer transients are attenuated by the PAPA and by the diversity of use that allows one stack-to-sewer route to act as a relief route for the other stacks.The network illustrated has an overall height of 12m. Pressure transients generated within thenetwork will propagate at the acoustic velocity in air . This implies pipe periods, from stack base to PAPA of approximately 0.08s and from stack base to stack base of approximately 0.15s.In order to simplify the output from the simulation no local trap seal protection is included—for example the traps could be fitted with either or both an AAV and PAPA as examples of active control. Traditional networks would of course include passive venting where separate vent stacks would be provided to atmosphere, however a sealed building would dispense with this venting arrangement.Fig.3.Four stack building drainage and vent system to demonstrate the viability of a sealed building system.Ideally the four sewer connections shown should be to separate collection drains so that diversity in the sewer network also acts to aid system self venting. In a complex building this requirement would not be arduous and would in all probability be the norm. It is envisagedthat the stack connections to the sewer network would be distributed and would be to a below ground drainage network that increased in diameter downstream. Other connections to the network would in all probability be from buildings that included the more traditional open vent system design so that a further level of diversity is added to offset any downstream sewer surcharge events of long duration. Similar considerations led to the current design guidance for dwellings.It is stressed that the network illustrated is representative of complex building drainage networks. The simulation will allow a range of appliance discharge and sewer imposed transient conditions to be investigated.The following appliance discharges and imposed sewer transients are considered:1. w.c. discharge to stacks 1–3 over a period 1–6s and a separate w.c. discharge to stack 4 between 2 and 7s.2. A minimum water flow in each stack continues throughout the simulation, set at 0.1L/s, to represent trailing water following earlier multiple appliance discharges.3. A 1s duration stack base surcharge event is assumed to occur in stack 1 at 2.5s.4. Sequential sewer transients imposed at the base of each stack in turn for 1.5s from 12 to 18s.The simulation will demonstrate the efficacy of both the concept of active surge control and inter-stack venting in enabling the system to be sealed, i.e. to have no high level roof penetrations and no vent stacks open to atmosphere outside the building envelope.The imposed water flows within the network are based on ‘real’ system values, being representative of current w.c. discharge characteristics in terms of peak flow, 2l/s, overall volume, 6l, and duration, 6s. The sewer transients at 30mm water gauge are representative but not excessive. Table 1 defines the w.c. discharge and sewer pressure profiles assumed.Table1. w.c. discharge and imposed sewer pressure characteristicsw.c. discharge characteristic Imposed sewer transient at stack baseTime Discharge flow Time PressureSeconds l/s Seconds Water gauge (mm)Start time 0.0 Start time 0.0+2 2.0 +0.5 30.0+4 2.0 +0.5 30.0+6 0.0 +0.5 0.05. Simulation conventionsIt should be noted that heights for the system stacks are measured positive upwards from the stack base in each case. This implies that entrained airflow towards the stack base is negative. Airflow entering the network from any AAVs installed will therefore be indicated as negative. Airflow exiting the network to the sewer connection will be negative.Airflow entering the network from the sewer connection or induced to flow up any stack will be positive.Water downflow in a vertical is however regarded as positive.Observing these conventions will allow the following simulation to be better understood.6. Water discharge to the networkTable 1 illustrates the w.c. discharges described above, simultaneous from 1s to stacks 1–3 and from 2s to stack 4. A base of stack surcharge is assumed in stack 1 from 2.5 to 3s. As a result it will be seen from Fig. 4 that entrained air downflows are established in pipes 1, 6 and 14 asexpected. However, the entrained airflow in pipe 19 is into the network from the sewer. Initially, as there is only a trickle water flow in pipe 19, the entrained airflow in pipe 19 due to the w.c. discharges already being carried by pipes 1, 6 and 14, is reversed, i.e. up the stack, and contributes to the entrained airflow demand in pipes 1, 6 and 14. The AAV on pipe 12 also contributes but initially this is a small proportion of the required airflow and the AAV flutters in response to local pressure conditions.Fig.4.Entrained airflows during appliance discharge.Following the w.c. discharge to stack 4 that establishes a water downflow in pipe 19 from 2 s onwards, the reversed airflow initially established diminishes due to the traction applied by the falling water film in that pipe. However, the suction pressures developed in the other three stacks still results in a continuing but reduced reversed airflow in pipe 19. As the water downflow in pipe 19 reaches its maximum value from 3 s onwards, the AAV on pipe 12 opens fully and an increased airflow from this source may be identified. The flutter stage is replaced by a fully open period from 3.5 to 5.5 s.Fig. 5 illustrates the air pressure profile from the stack base in both stacks 1 and 4 at 2.5 s into the simulation. The air pressure in stack 4 demonstrates a pressure gradient compatible with the reversed airflow mentioned above. The air pressure profile in stack 1 is typical for a stack carrying an annular water downflow and demonstrates the establishment of a positive backpressure due to the water curtain at the base of the stack.Fig.5.Air pressure profile in stacks 1 and 4 illustrating the pressure gradient driving the reversed airflow in pipe 19.The initial collapsed volume of the PAPA installed on pipe 13 was 0.4l, with a fully expanded volume of 40l, however due to its small initial volume it may be regarded as collapsed during this phase of the simulation.7. Surcharge at base of stack 1Fig. 6 indicates a surcharge at the base of stack 1, pipe 1 from 2.5 to 3 s. The entrained airflow in pipe 1 reduces to zero at the stack base and a pressure transient is generated within that stack, Fig.6. The impact of this transient will also be seen later in a discussion of the trap seal responses for the network.Fig.6.Air pressure levels within the network during the w.c. discharge phase of the simulation. Note surcharge at base stack 1, pipe 1 at 2.5s.It will also be seen, Fig. 6, that the predicted pressure at the base of pipes 1, 6 and 14, in the absence of surcharge, conform to that normally expected, namely a small positive back pressure as the entrained air is forced through the water curtain at the base of the stack and into the sewer. In the case of stack 4, pipe 19, the reversed airflow drawn into the stack demonstrates a pressure drop as it traverses the water curtain present at that stack base.The simulation allows the air pressure profiles up stack 1 to be modelled during,and following, the surcharge illustrated in Fig. 6. Fig. 7(a) and (b) illustrate the air pressure profiles in the stack from 2.0 to 3.0 s, the increasing and decreasing phases of the transient propagation being presented sequentially. The traces illustrate the propagation of the positive transient up the stack as well as the pressure oscillations derived from the reflection of the transient at the stack termination at the AAV/PAPA junction at the upper end of pipe 11.Fig.7.(a) Sequential air pressure profiles in stack 1 during initial phase of stack base surcharge. (b) Sequential air pressure profiles in stack 1 during final phase of stack base surcharge.8. Sewer imposed transientsTable 2 illustrates the imposition of a series of sequential sewer transients at the base of eachstack. Fig. 8 demonstrates a pattern that indicates the operation of both the PAPA installed on pipe 13 and the self-venting provided by stack interconnection.Fig.8.Entraind airflows as a result of sewer imposed pressure transients.As the positive pressure is imposed at the base of pipe 1 at 12 s, airflow is driven up stack 1 towards the PAPA connection. However, as the base of the other stacks have not a yet had positive sewer pressure levels imposed, a secondary airflow path is established downwards to the sewer connection in each of stacks 2–4, as shown by the negative airflows in Fig. 8.As the imposed transient abates so the reversed flow reduces and the PAPA discharges air to the network, again demonstrated by the simulation, Fig. 8. This pattern repeats as each of the stacks is subjected to a sewer transient.Fig. 9 illustrates typical air pressure profiles in stacks 1 and 2. The pressure gradient in stack 2 confirms the airflow direction up the stack towards the AAV/PAPA junction. It will be seen that pressure continues to decrease down stack 1 until it recovers, pipes 1 and 3, due to the effect of the continuing waterflow in those pipes.The PAPA installation reacts to the sewer transients by absorbing airflow, Fig. 10. The PAPA will expand until the accumulated air inflow reaches its assumed 40 l volume. At that point the PAPA will pressurize and will assist the airflow out of the network via the stacks unaffected by the imposed positive sewer transient. Note that as the sewer transient is applied sequentially from stacks 1–4 this pattern is repeated. The volume of the high level PAPA, together with any others introduced into a more complex network, could be adapted to ensure that no system pressurization occurred.Fig.9.Air pressure profile in stack 1 and 2 during the sewer imposed transient in stack 2, 15s into the simulation.Fig.10.PAPA volume and AAV throughflow during simulation.The effect of sequential transients at each of the stacks is identifiable as the PAPA volume decreases between transients due to the entrained airflow maintained by the residual water flows in each stack.9. Trap seal oscillation and retentionThe appliance traps connected to the network monitor and respond to the local branch air pressures. The model provides a simulation of trap seal deflection, as well as final retention. Fig. 11(a,b) present the trap seal oscillations for one trap on each of the stacks 1 and 2, respectively. As the air pressure falls in the network, the water column in the trap is displaced so that the appliance side water level falls. However, the system side level is governed by the level of the branch entry connection so that water is lost to the network. This effect is illustrated in both Fig. 11(a) and (b).Transient conditions in the network result in trap seal oscillation, however at the end of the event the trap seal will have lost water that can only be replenished by the next appliance usage. If the transient effects are severe than the trap may become totally depleted allowing a potential cross contamination route from the network to habitable space. Fig. 11(a) and (b) illustrate the trap seal retention at the end of the imposed network transients.Fig.11.(a) Trap seal oscillation, trap 2. (b) Trap seal oscillation, trap 7.Fig. 11(a), representing the trap on pipe 2, illustrates the expected induced siphonage of trap seal water into the network as the stack pressure falls. The surcharge event in stack 1 interrupts this process at 2s. The trap oscillations abate following the cessation of water downflow in stack 1. The imposition of a sewer transient is apparent at 12s by the water surface level rising in the appliance side of the trap. A more severe transient could ha ve resulted in ‘bubbling through’ at this stage if the trap system side water surface level fell to the lowest point of the U-bend.The trap seal oscillations for traps on pipes 7, Fig. 11(b) and 15, are identical to each other until the sequential imposition of sewer transients at 14 and 16s. Note that thesurcharge in pipe 1 does not affect these traps as they are remote from the base of stack 1. The trap on pipe 20 displays an initial reduction in pressure due to the delay in applied water downflow. The sewer transient in pipe 19 affects this trap at around 18s.As a result of the pressure transients arriving at each trap during the simulation there will be a loss of trap seal water. This overall effect results in each trap displaying an individual water seal retention that depends entirely on the usage of the network. Trap 2 retains 32mm water seal while traps 7 and 15 retain 33mm. Trap 20 is reduced to 26mm water seal. Note that the traps on pipes 7 and 15 were exposed to the same levels of transient pressure despite the time difference in arrival of the sewer transients. Fig. 11(a) and (b) illustrate the oscillations of the trap seal column as a result of the solution of the trap seal boundary condition, Eq. (10), with the appropriate C+ characteristic. This boundary condition solution continually monitors the water loss from the trap and at the end of the event yields a trap seal retention value. In the example illustrated the initial trap seal values were taken as 50mm of water, common for appliances such as w.c.'s and sinks.10. Conclusion—viability of a sealed building drainage and vent systemThe simulation presented confirms that a sealed building drainage system utilizing active transient control would be a viable design option. A sealed building drainage system would offer the following advantages:• System s ecurity would be immeasurably enhanced as all high-level open system terminations would be redundant.• System complexity would be reduced while system predictability would increase.• Space and material savings would be achieved within the construction ph ase of any installation.These benefits would be realized provided that active transient control and suppression was incorporated into the design in the form of both AAV to suppress negative transients and variable volume containment devices (PAPA) to control positive transients.The diversity inherent in the operation of both building drainage and vent systems and the sewers connected to the building have a role in providing interconnected relief paths as part of the system solution.The method of characteristics based finite difference simulation presented has provided output consistent with expectations for the operation of the sealed system studied. The accuracy of the simulation in other recent applications, including the accurate corroboration of the SARS spread mechanism within the Amoy Gardens complex in Hong Kong in 2003, provides a confidence level in the results presented.。
建筑给排水英文文章一、IntroductionIn the field of architecture, plumbing systems play a crucial role in providing clean water and removing waste from a building. Effective and efficient building plumbing systems are essential for the health and safety of occupants. This article will explore the various aspects of building plumbing systems, including design principles, materials used, installation methods, and maintenance requirements.二、Design PrinciplesA well-designed plumbing system in a building relies on several key principles:1. Water Supply DesignThe design of a water supply system involves determining the source of water, calculating the required flow rate, and sizing the pipes accordingly. Factors such as building size, occupancy, and water demand must be considered. Additionally, backflow prevention devices are installed to prevent contamination of the water supply.2. Drainage System DesignThe drainage system design focuses on removing wastewater from the building and ensuring proper disposal. Gravity is commonly used to move wastewater through a series of pipes and drains. Proper slope, pipe diameter, and venting are important considerations to prevent blockages, odors, and sewer gas leaks.3. Fixture LayoutThe layout of plumbing fixtures, such as sinks, toilets, and showers, should be carefully planned to optimize water usage, convenience, andaccessibility. Adequate space and accessibility for maintenance should be considered during the design phase.三、Materials UsedVarious materials are used in the construction of plumbing systems. The choice of materials depends on factors such as the type of water supply, budget, and local regulations. Common materials used include:1. PipesPipes are typically made of materials such as copper, galvanized steel, PVC (polyvinyl chloride), and PEX (cross-linked polyethylene). Each material has its advantages and disadvantages, such as durability, cost, ease of installation, and resistance to corrosion.2. Fittings and ValvesFittings and valves connect and control the flow of water within the plumbing system. They are available in materials like brass, copper, and plastic. The choice of fittings and valves depends on the specific requirements of the system and its intended use.四、Installation MethodsProper installation of plumbing systems is crucial to ensure their functionality and longevity. Different installation methods are used depending on the building structure and plumbing system design. Some common installation methods include:1. Traditional Open-Cut MethodThis method involves excavating trenches for the placement of pipes. It allows for easy access and repair but can be time-consuming and disruptive, especially in existing buildings.2. Trenchless TechnologyTrenchless technology, such as pipe bursting and pipe lining, is gaining popularity due to its minimal disruption and cost-effectiveness. It involves using specialized equipment to repair or replace pipes without the need for extensive excavation.五、Maintenance RequirementsRegular maintenance is essential to keep building plumbing systems in optimal condition. Neglecting maintenance can lead to leaks, blockages, and water damage. Some important maintenance requirements include:1. Regular InspectionsPeriodic inspections of the plumbing system can help identify any potential issues before they escalate into costly repairs. Inspections should include checking for leaks, proper drainage flow, and functioning of valves and fixtures.2. Clearing BlockagesBlockages in drains and pipes should be promptly cleared to prevent backups and plumbing system failures. This may involve using mechanical tools or chemicals, depending on the nature of the blockage.3. Water Heater MaintenanceWater heaters should be inspected and serviced regularly to ensure efficient and safe operation. This includes checking for leaks, sediment buildup, and testing the pressure relief valve.六、ConclusionBuilding plumbing systems are vital for the functionality and comfort of a building. Proper design, choice of materials, installation methods, and regular maintenance are key factors in ensuring the performance and longevity of these systems. By following the principles discussed inthis article, architects, engineers, and building owners can createreliable and efficient plumbing systems that meet the needs of occupants while adhering to relevant regulations.。
中英文对照外文翻译(文档含英文原文和中文翻译)Short and Long Term Advantage roof drainage design performance Decade has witnessed great changes in the design of the roof drainage system recently, particularly, siphon rainwater drainage system has been gradually improved, and there is likely to be the key application. At the same time these changes, urban drainage system design has undergone tremendous changes, because the scope of a wider urban drainage system design for sustainable development, as well as people for climate change flooding more attention. The main contents of this article is how to design roof drainage systems and make a good performance. Special attention is how to get rid of bad habits already formed the design, but also need to consider innovative roof drainage system, such as green roofs and rainwater harvesting systems.Practical application: In the past few years, the design of the roof rainwater drainage system has undergone tremendous changes. On large buildings, siphon rainwater drainage technology has been very common, as well as green roofs because it is conducive to green development, being more and more applications. Taking into account the ongoing research, this article focuses on how to effectively design a variety of roof rainwater drainage system, and make it achieve the desired design effect.1. IntroductionIn the past decade, the city and the water drainage system design has been widely accepted thinking about sustainable urban drainage system, or the optimal management direction. The main principles of the design of these systems is both a local level in line with the quality of development, but also to create some economic benefits for the investors. This principle has led to the development of new changes in the sump. Although the application of such a device isgradually reduced, but the urban environment relatively high demand areas still require 100% waterproof and rapid drainage, such as the roof. Typically roof drainage system in the design, construction and maintenance has not been given due attention. Although the drainage system investment costs account for only a small portion of the total construction investment, but not able to judge the loss caused by poor design.There are two different forms of roof drainage system design methods, namely the traditional and siphon method. Traditional systems rely on atmospheric pressure work, the drive ram affected sink flow depth. Therefore, the conventional roof drainage systems require a relatively large diameter vertical drop tube, prior to discharge, all devices must be connected to the groundwater collection pipe network. In contrast, siphonic roof drainage pipe systems are generally designed to full flow (turbulent flow means that require less exhaust pipe), which will form a negative pressure, the larger the higher flow rate and pressure head. Typically siphon system requires less down pipe work under negative pressure to the water distribution network can mean higher altitude work, thereby reducing the amount of underground pipe network.Both systems consists of three parts: the roof, rainwater collection pipes, pipe network.All of these elements are able to change the water pressure distribution system. This section focuses on the role and performance of each part. Due to the principle of siphon system has not been well understood, resulting argument is relatively small, this article will highlight siphon system.2. RoofThe roof is usually designed by the architect, designer and not by the drainage design. There are three main roof.2.1 Flat roofFlat roofs are used in industrial buildings less rainfall regions and countries. This roof is not completely flat, but lower than the minimum roof slope may require. For example, the United Kingdom require maximum slope of 10 °. Setting minimum slope in order to avoid any unnecessary water.Despite the flat roof if it is not properly maintained will have more problems, but it will reduce the dead zone within the building, and the ratio of sloping roofs in favor of indoor air.2.2 sloping roofsMost residential and commercial buildings are pitched roof, inclined roof is the biggest advantage can quickly drain, thereby reducing leakage. In temperate regions, we need to consider carrying roof snow load. Once it rains, rainfall through the sloping roofs can be determined by calculation. When rainfall data can be used, you can use the kinematic theory to solve such problems.2.3 green roof (flat or inclined)It can prove roof is the oldest green roofs, including rainfall can reduce or disperse roof planted with plants. It can be planted with trees and shrubs roof garden, it can also be a vegetated roof light carpet. Wherein the latter technique has been widely used. Some of these applications tend to focus on aesthetic requirements and are often used in green development. Since the aesthetic requirements and pressure requirements, as well as green roofs thermal insulation function, reduce the heat island effect, silencer effect, extend the life of the roof.Green roofs in Germany, the most widely used, followed in North America, but to consider the impact on the aesthetics. Germany is by far the most experienced countries in the 19th centuryhave practical application, then as an alternative to reduce the risk of fire tar roof an option in urban areas. Germany is currently the main research question on the cultivation of other issues to consider smaller cities. A study from 1987 to 1989, was found packed with 70 mm thick green roof can be reduced by 60% -80% of heat loss. In a Canadian work computer model based on the roof indicates that as long as the sump, the area can reach 70% of the roof area can be reduced by 60 percent in one year, the same model was also used for artificial rainfall, which the results indicate that rainfall in the catchment season helps to drain away rainwater.However, none of these studies show that green roofs can play a useful role in the rainfall season, or how high collection efficiency of water supply. The United States did some tests, as long as the green roofs regular watering, can reduce 65 percent of the runoff in a rainfall. America's most authoritative green roof guidelines by the New Jersey state environmental agencies promulgated. The main principle is to solve the structural problems of light, and how can the normal drainage after two years.Rainfall period is based on the probability of failure is determined. The system is typically based on rainfall during rainstorms two minutes, two minutes, have a choice. Although this model will get more traffic, but there is no other better alternative. Studies have shown that the traditional model is applied to study green roofs are premature.Loss factor than traditional roof records should be small, about 98.7%.Peak flow will be reduced, although not penetrate, the surface roughness but also have a significant impact.Concentrated rainfall than two minutes for a long time, especially for large roof areas, such as public buildings, commercial buildings, industrial buildings.Urban drainage design should also consider other factors, for a complex system, a green roof in a rain is not enough. Water flow duration curve shows a longer than traditional systems. And two independent and will affect between is possible, which requires a more precise time period. 3. Rainwater CollectorBasic requirements rainwater collector is designed to be able to accommodate rainfall rainstorms. Although it is possible to make a slightly inclined roof drainage purposes, but the nature of the construction industry and building settlement will become flat roof Typically, the tank is placed in a horizontal, sectional view of the water is outwardly inclined, which the role of hydrostatic.3.1 drain outletAnalyzing rainwater collector has sufficient volume is the key to the sump outlet external setting conditions. Also affect the flow rate into the storm water drainage system piping, but also affect the depth of the water catchment. Although the depth of the sump will not bring any particular problems, but too deep can cause excessive sump.Numerous studies in the 1980s showed that the flow of conventional roof drainage system outlet can be divided into two cases. It depends on the size of the depth and size of the outlet. When the water depth is less than half the diameter of the outlet, the flow of the first type, and the outlet of the flow can be calculated by an appropriate equation; water depth increases, exports are slowly clogging the flow will become another form forms, at the same time, the flow of exports can be obtained through other equations. While conventional roof drainage systems are designed to be free-draining, but may cause limitations encountered in the design of the flow is not free. In this case, it will require additional depth.Siphon roof drainage systems, the outlet is designed to be submerged stream. In this case, the depth of the outlet of the decision is more complicated, because the design of the sump depends on the flow. Recent studies have shown that conventional roof drainage systems use a variety of non-standard catchment, their depth and height, bigger than the diameter of the outlet. This will eventually result in a siphon effect. For a given catchment, the flow depends on the starting end of the drop tube diameter. A similar phenomenon has also been used to study the standard catchment, in these circumstances, only limited siphon action occurs within relatively close distance from the exit.3.2 tank flow classificationIn the complex flow sump outlet flow classification, can be seen from Table 2a, the flow will be uniform layering, regardless of whether the same inlet flow. Table 2b and 2c show, export distribution will greatly influence the flow.When the outlet is not a free jet, sump outlet complex flow classification is difficult to describe. Because each catchment tank pressures are likely to be merged. For example, the siphon tube system design point is at near full jet outlet flow classification depends on the energy loss of each branch.3.3 hydrostatic sectionalSump shape of the water surface in the canal can be classified according to the flow equation. In most cases, a low flow rate means that there is less friction loss, if exports are free jet, the friction loss is negligible cross-section through the hydrostatic equation 1 to determine the horizontal distance.Where Q-- flow (m3 / s)T- surface width (m)g- acceleration of gravity (m / s2)F- flow area (m2)Equation 1 can not be ignored when the friction required to correct (or very long pipe velocity is large), or not a free jet.3.4 The current design methodsThe previous discussion has highlighted the main factors that should be considered with sink design. However, without the help of a certain number of models, computing hydrostatic sectional roof drainage system, the volume of the sump is possible. This large commercial and manufacturing industry, is a development opportunity, you can merge several kilometers of water routes. Thus, the conventional drainage system sump design methods are mainly based on experience, and assume that exports are free jet.Sump location in the building, it may cause the example to fail.Different interface sumpExcept in the case cited above, but also allows designers to use empirical data.3.5 Digital ModelLarge number of digital models can be used to accurately describe the flow of any form of catchment tank, regardless of whether the roof flows stable. An example of this model is a combination of roof space model. This model enables users to classify different aspects of the data indicated, includes: details of the rains, the roof surface drainage and other details. Kinematics have also been used to study rainwater tank to flow from the research collection. A typical method is based on open system to solve a basic problem of spatial mobility. This model automaticallyresolve the sump outlet flow situation, but also to deal with the case of free jet can also be simulated space limited mobility and submerged discharge. Output values include depth and flow rate.Currently, the model is essentially just a variety of research tools, but also through practical engineering test. However, we should face up to the various role models.4 pipe systems groupComposition in the form and scope of the tube group determines the roof drainage system relies mainly on the traditional system or siphon action.4.1 Traditional stormwater systemsConventional roof drainage systems, the ground plane is generally vertical pipe-line network, connected to the sump outlet and underground drainage systems, critical systems as well as compensating tube. It should be emphasized that the angle between the ground and the compensating tube is less than 10 °. Capacity of the entire system relies mainly on the outlet tube instead of down.Flow vertical tube is usually free-flowing, full of only 33%, the efficiency depends on the excess length of the tube. If the drop tube long enough (typically greater than 5m), there may be an annular flow. Similarly, under normal circumstances flow compensation pipe is free-flowing, full of up to 70%. Such designed process both for the design, various equations can also be used.4.2 Siphon roof drainage systemIn contrast with the traditional drainage systems, Siphon roof drainage system relies on air flow outside the system, and the tube is full pipe flow stream.The designs are usually made on the assumption that the design of heavy rain, the system can quickly siphon discharge rainwater. This assumption allows the application of hydrostatic siphon system theory. Often used steady flow energy equation. While this approach ignores the small amount of energy loss at the entrance, but after the experiment showed that there are still conducive to practical use.However, steady-state design methods in the siphon system is exposed to rain when the system does not meet the standard requirements or changes in rainfall intensity is large is not applied. In the first case, there will be some mixing of air quality, annular flow occurs. These problems are not integrated in the system when more serious. Because usually designed rains are common, it is clear now design methodology over time may not apply to siphon system. This is a major disadvantage, because the design of the main problem is the noise and vibration problems.Despite the disadvantages of the prior design approach, but a lot of the world's very few engineering failure reports. When a failure occurs, most likely for the following reasons: An incorrect understanding of the operation pointsSubstandard materials listInstallation defectsMaintenance mismanagementTo overcome these disadvantages, we have recently launched a series of research projects, to discuss the siphon system, and the development of digital models. From this work we learn a lot. In contrast with conventional design methods of some assumptions, siphon system mainly has the following aspects:1) non-flow system of full flow2) levels of certain pipe-flowing full pipe flow3) full pipe flow downstream propagation through a vertical pipe, riser, etc.4) the inner tube flow occurs over the vertical section, the system to reduce the pressure5) downward tube is full pipe flow, there will be air lock6) appears completely siphon action until well into the air system is lower than a certain levelTable 4a column data indicate that below the design point, the system will siphon unstable flow, depth of the water collecting tank is insufficient to maintain the siphon action. Table 4b show that the unsteady flow in siphon system when it will appear.Table 5 lists the data output of a digital model. It can be seen that the model can accurately describe the siphon action, siphon and steady state, the data also show that the model can accurately describe the complex siphon action.5 ConclusionThis article has illustrated the critical roof drainage systems, but these are often overlooked in the urban drainage system design. This article also shows that the design process is a complex process, rely mainly on the performance of exports. The following conclusions are based on the design summed up:1) Run depend on three interacting parts: the roof, sump, water pipes2) Green roofs can reduce traffic and beautify the city3) the export performance of the system is essential4) siphon drainage system have a greater advantage in large-scale projects, but must be considered high maintenance costs5) Design siphon drainage system should consider additional capacity and operational issuesAlthough the green roof is a more attractive option, but the traditional roof of a building in the country will continue to dominate. Green roofs will be gradually developed, and gradually been widely accepted. Similarly, the roof drainage system shown effective that it will continue to play a huge role in the commercial building drainage systems.Roof drainage system of the greatest threats from climate change, existing systems tend to be not simply aging; rainfall patterns of change will result in inefficient operation, self-cleaning rate will be reduced. Changes in wind speed and the roof will also accelerate the aging of the roof, it is necessary to carry out maintenance. Taking into account the climate change, the increase in materials, roof collected rainwater will be more extensive. Currently, the amount of rain around the globe per person per day 7-300 liters in the UK, with an average consumption of 145L / h / d, of which only about one liter is used by people, about 30 per cent of the toilet, study shows If water shortage, rainwater collected on the roof of developed and developing countries are recommended approach.屋顶排水设计性能的近期与远期优势最近十年见证了屋顶排水系统设计方面的巨大变化,特别的是,虹吸雨水排水系统已经得到逐步改善,并且有可能得到重点应用。
中英文对照外文翻译文献(文档含英文原文和中文翻译)原文:Optimum combination of water drainage,water supply and eco-environment protection in coal-accumulated basin of North ChinaAbstract The conflict among water drainage,water supply and eco-environment protection is getting more and more serious due to the irrational drainage and exploitation of ground water resources in coal-accumulated basins of North China.Efficient solutions to the conflict are tomaintain long-term dynamic balance between input and output of theground water basins,and to try to improve resourcification of the mine water.All solutions must guarantee the eco-environment quality.This paper presents a new idea of optimum combination of water drainage,water supply and eco-environment protection so as to solve theproblem of unstable mine water supply,which is caused by the changeable water drainage for the whole combination system.Both the management of hydraulic techniques and constraints in economy,society,ecology,environment,insustuial structural adjustments and sustainable developments have been taken into account.Since the traditional and separate management of different departments of water drainage,water supply and eco-environment protection is broken up these departments work together to avoid repeated geological survey and specific evaluation calculations so that large amount of national investment can be saved and precise calculation for the whole system can be obtained.In the light of the conflict of water drainage,water supply and eco-environment protection in a typical sector in Jiaozuo coal mine,a case study puts forward an optimum combination scheme,in which a maximum economic benefit objective is constrained by multiple factors.The scheme provides a very important scientific base for finding a sustainable development strategy.Keywords combination system of water drainage,water supply and eco-environment protection,optimal combination,resourcification of mine water.1Analyses of necessity for the combinationThere are three related problems in the basin.It is well known that the major mine-hydrogeological characteristics of the coal accumulated basin in North China display a stereo water-filling structure,which is formed by multi-layer aquifers connected hydraulically together with various kinds of inner or outer boundaries.Mine water hazards have seriously restricted the healthy development of coal industry in China because of more water-filling sources and stronger water-filling capacity in coal mines of the basin.Coal reserves in the basin are threatened by the water hazards.In Fengfeng,Xingtai,Jiaozuo,Zibao,Huaibei and Huainan coal mine districts,for example,it is estimatedthat coal reserves are threatened by the water hazards up to 52%,71.%40,%,60%,48%and 90%of total prospecting reserves respectively.It is obvious that un-mining phenomenon caused by the water hazards is serious.Water-bursting accidents under coal layers have seriously influenced safe production.Some statistical data show that there were 17 water-bursting accidents with over 1 m3/s inflow from 1985.Water drainage is an increasing burden on coal mines threatened by water hazards:high cost of water drainage raises coal prices and reduces profits of the enterprise.On the other hand,it is more and more difficult to meet the demand of water supply in coal mine districts in the basin.The reasons are not only arid and semi-arid weather conditions,but also a large amount of water drainage with deep drawdown in coal mines and irrational water exploitation.The deterioration of eco-environment is another problem.Phenomena of land surface karst collapse can be found.Many famous karst springs,which are discharge points for the whole karst groundwater syatem,stop flowing or their discharge rates decrease on a large scale.Desert cremophytes in large areas in west China die because of falling groundwater level.These three problems are related and contradictory.In order to solve the problems while ensuring safe mining,meeting water resource demands and slowing down the pace of eco-environment deterioration,it is necessary to study the optimum combination of water drainage,water supply and eco-environment protection in the basin.2The state of the art of research and the problemsAlthough research into the combination of water drainage and water supply started much earlier in some countries,their conception is simple and some shortcomings remain in their study on the theory and pattern of combination.China’s research history on the combination can be divided into three stages.The first stage is the utilization of mine water.A century ago mine water started to be used as water supply for mines.But the utilization scale and efficiency were quite limited at that time.The second stage is a comprehensive one:mine water was used while water hazards were harnessed.Great progress was made both in theory and practice of the combination.For example,the combination of water drainage and water supply not only means the utilization of mine water,but also means that it is a technique of preventing water hazards.It is unfortunate,however,that the combination research in this stage offered less sense ofeco-environment protection.Optimum combination management of water drainage,water supply and eco-environment protection is the third stage.Main features in this stage are to widen traditional research,and to establish an economic-hydraulic management model,in which safe mining,eco-environment protection and sustainable development demands,etc.are simultaneously considered as constraint conditions.3Trinity systemThe trinity system combines water drainage,water supply and eco-environment quality protection.The water-collecting structures of the system consist of land surface pumping wells in the mines,shallow land surface well in groundwater recharge areas and artificial relief wells under the mines.Both integration and coordination for the trinity system are distinguished according to the combination.The integration for the system means to utilize drainage water under the mines and pump water onto the land surface as water supply for different purposes without harming the eco-environmental quality.The coal mines are not only drainage sites,but also water supply sources.The purpose of drilling pumping wells on the land surface is to eliminate special influences on different consumers,which are caused by terminating drainage processes under the mines due to unexpected accidents in mining.The coordination for the system means to bulid some water supply sources for different consumers while ensuring eco-environmental quality in groundwater recharge positions,where pumping groundwater is quite effective on lowering groundwater heads in the mine areas.Itintercepts in advance the recharging groundwater flow towards the mines,which may not only provide consumers with good quality groundwater,achieve the goal of dropping down groundwater heads in the mines,but also effectively reduce the high costs of drainage and water treatment,which are needed by traditional dewatering measures with large drainage flow rates under the mines.The coordination changes the traditional passive pattern of preventing and controlling groundwater hazards under the mines into that of active surface interception.Both very developed karst flow belts and accumulated groundwater recharge ones under the ground are relatively ideal interceptive coordination positions in the system.For the integration of the trinity system,artificial relief wells under the mines and the land surface pumping wells mainly penetrate into direct thin bedded karst aquifers interbedded with the mining coal layers,while for the coordination of the system,the shallow land surface wells mainly penetrate into very thick karst aquifer.Therefore,hydrogeological conceptual model for the system involves the multi-layer aquifers connected hydraulically by different inner boundaries.Setting up stereo hydrogeological conceptual models and corresponding mathematical models is a prerequisite for solving the managemental problems for the system.Management of the trinity system not only considers the effects of lowering groundwater heads and safe operation for water drainage subsystem,but also pays attention to the water demands for water supply subsystem and quality changes for eco-environment protection subsystem.They play the same important role in the whole combination system.It controls the groundwater heads in each aquifer to satisfy the conditions of safe mining with certain water head pressures in the mines,and to guarantee a certain amount of water supply for the mines and near areas,but the maximum drawdown of groundwater must not be ex ceded,which may result in lowering eco-environmental quality.4Economic-hydraulic management modelIn the trinity system management,groundwater resources in the mines and nearby areas,which are assessed on the premise of eco-environment qualities and safe operation in the mines,may be provided as water supply prices,drainage costs,transportation costs(including pipeline and purchasing the land costs)and groundwater quality treatment costs for the three different waterconsumers,the optimum management models may automatically allocate to each consumer a certain amount of groundwater resources and a concrete water supply scenario based on comparisons of each consumer’s economic contribution to the whole system in objective function.Therefore the management studies on the optimal combination among water drainage,water supply and eco-environment protection involve both the management of groundwater hydraulic techniques and the economic evaluations,eco-environment quality protection and industrial structure programs.In addition to realizing an economic operation,they also guarantee a safe operation which is a key point for the combination of the whole system.5The management model for the trinity system can reach water supply goals with drainage water under the mines and the land surface pumping water on the premise of ensuring eco-environmental quality.And it can make use of one model to lay down comprehensively optimum management scenarios for each subsystem by means of selecting proper constraints and maximum economic benefit objective produced by multiple water consumers.The model can raise the security and reliability of operation for the whole trinity system,and the drainage water can be forecast for the mines and the management of water supply resource and the evaluation of eco-environment quality can be performed at the same time so as to respectively stop the separate or closed management,of departments of drainage water,water supply and eco-environment protection from geological survey stage to management evaluation.This,in economic aspect,can not only avoid much geological survery and special assessment work which are often repeated by the three departments,and save a lot of funds,but also ,in technical aspect,make use of one model to simultaneously consider interference and influence on each other for different groundwater seepage fields so as to guarantee calculating precision of the forecast,the management and the evaluation work.The economic-hydraulic management model can be expressed as follows.6 A case studyA typical sector is chosen.It is located in the east of Jiaozuo coal mine,Henan Province,China.Itconsists of three mines:Hanwang Mine,Yanmazhuang Mine and Jiulishan Mine.The land surface is flat,and the whole area is about 30 km2.An intermittent river Shanmen flows through the sector from the north to the south.Average annual precipitation in the sector is about 662.3mm.Theprecipitation mainly concentrates inJune,July,August and September each year.Strata in the sector consist of very thick limestone in Middle Ordovician,coal-bearing rock series in Permo Carboniferous and loose deposits in Quaternary.There are four groups of faulted structures.The first is in northeast-southwest direction such as F3 and F1..The second is in the northwest-southeast direction such as Fangzhuang fault.The third is in the east-west direction such as Fenghuangling fault.The last is almost in north-south.These faults are all found to be normal faults with a high degree of dip angle.Four major aquifers have been found in the sector.The top one is a semi-confined porous aquifer.The next one is a very thin bedded limeston aquifer.The third is a thin bedded limestone aquifer.The last one at the bottom is a very thick limestone aquifer.Objective function of the management model is designed to be maximum economic benefit produced by domestic,industrial and agricultural water supply.Policy making variables of the model are considered as the domestic,industrial and agricultural groundwater supply rates in every management time step,and they are supplied by artificial relief flow wells under the mines,the land surface pumping wells in the mines and the shallow land surface wells in the groundwater recharge areas.All the 135 policy making variables are chosen in the model,27 for drainage wells under the mines in aquifer,27 for the land surface pumping wells in the mine districts in aquifer 27 in aquifer 27 in aquifer O2 27 for the shallow land surface wells in aquifer O2Based on the problems,the following constraint conditions should be considered:(1)Safe mining constraint with groundwater pressure in aquifer L8.There are altogether three coalmines in the typical sector,i.e.Hanwang Mine,Yanmazhuang Mine and Jiulishan Mine.Elevations of mining level for these mines are different because it is about 88-150 m in the second mining level for Hanwang Mine,and -200m in the second mining level for Yanmazhuang Mine,and-225 m in the first mining level for Jiulishan Mine.According to mining experiences,pressure-loaded heights for groundwater heads in safe mining state are considered as about 100-130m.Therefore,the groundwater level drawdowns in the three management time steps for aquifer L8 at three mines have to be equivalent to safe drawdown values at least in order to pervert groundwater hazards under the mines and to guarantee their safe operation.(2)Geological eco-environment quality constraint.In order to prevernt groundwater leakage fromupper contaminater porous aquifer into bottom one and then to seepage further down to contaminate the thin bedded limestone aquifer in the position of buried outcrop,the groundwater heads in the bottom porous aquifer must keep a certain height,i.e.the groundwater drawdowns in it are not allowed to exceed maximum values.(3)Groundwater head constraint at the shallow land surface wells in aquifer O2,The shallow landsurface wells should penetrate in aquifer O2 in order to avoid geological environment hazards,such as karst collapse and deep karst groundwater contamination.Groundwater head drawdowns in aquifer O2 for the shallow land surface wells are not allowed to exceed criticalvalues.(4)Industrial water supply constraint for the groundwater source in aquifer O2 .The rate ofindustrial water supply needed by the planned thermal power plant in the north of the sectoris designed to be 1.5 m3/s according to the comprehensive design of the system in thesector.In order to meet the demands of water,the rate industrial water supply for thegroundwater source in aquifer O2 in every management time step must be equivalent at leastto 1.5 m3/s.(5)Maximum amount constraint of groundwater resource available for abstraction.In order tomaintain the balance of the groundwater system in the sector for a long time and to avoid anyharmful results caused by continuous falling of groundwater head,the sum of groundwaterabstraction in each management time step is not allowed to exceed the maximum amount ofgroundwater resource available for abstraction.Since there is not only water drainage in the mines,but also water supply in the whole combination system,management period for the model is selected from June 1,1978 to May 31,1979,in which annual average rate of precipitation is about 50%.Management time steps for the period are divided into three.The first one is from June to September,the second from October to next January,and the last one from next February to May.According to comprehensive information about actual economic ability,economic development program and industrial structure adjustment in the sector at present and in the near future,and different association forms of water collecting structures among the land surface pumping wells,the shallow land surface wells and artificial relief flow wells under the mines,this paper designs 12 management scenarious,all of which take the safe operation in the trinity system as the most important condition.After making comparisons of optimum calculation results for the 12 scenarious,this paper comes to a conclusion that scenarios is the most ideal and applicable one for the typical sector.This scenario not only considers the effective dewatering advantage of the artificial relief flow wells under the mines and safe stable water supply advantage of the land surface pumping wells,but also pays attention to the disadvantage of low safe guaranty rate for the relief flow wells under the mines for water supply and of large drilling investment in the land surface pumping wells.Meanwhile,eh shallow land surface wells inaquifer O2in this scenario would not only provide water supply for the thermal power plant as planned,but also play an important role in dewatering the bottom aquifer,which is major recharge source of groundwater for the mines.If the drainage subsystem under the mines runs normally,this scenario could fully offer the effective dewatering functions of the artificial relief flow wells under the mines,and makes the trinity system operate normally.But if the drainage subsystem has to stop suddenly because of unexpected accidents,the scenario could still fully utilize the land surface pumping wells and the shallow land surface wells,and increae their pumping rates in order to make up for temporary shortage of water supply for the trinity system and to make its economic losses reduced to a minimum extent.Increasing groundwater abstraction rate for the land surface pumping wells and the shallow land surface wells,in fact,is very favorable for harnessing the water-accidents under the mines and for recovery production of the mines.To sum up,this scenario sets up a new pattern for the combination of water drainage,water supply and eco-environment protection.It solves quite well the conflicts between the low safe guaranty rate and the effective dewatering result for the artificial relief flow wells under the mines.It makes full use of beneficial aspect of the conflicts,and meanwhile compensates for the unbeneficial one by arranging the land surface pumping wells in the coal mine districts.Therefore,this scenario should be comprehensive and feasible.In this scenario,Hanwan Mine,Yanmazhuang Mine and Jiulishan Mine are distributed optimally for certain amount of domestic and industrial water supply,but not for much agricultural water supply.The land surface pumping wells are also distributed for different purposes of water supply.The water supply for the thermal power plant (1.5 m3/s) is provided by the shallow land surface prehensive effects,produced by the above three kinds of water collecting structures,completely satisfy all of the constraint conditions in the management model,and achieve an extremely good economic objective of 16.520551million RMB yuan per year.In order to examine the uncertainty of the management model,12management scenarios are all tested with sensitive analysis.7Conclusion(1)The optimum combination research among water drainage,water supply and eco-environmentprotection is of great theoretical significance and application value in the basin of North China for solving unbalanced relation between water supply and demands,developing new potential water supply sources and protecting weak eco-environment.(2)The combination research is concerned not only with hydraulic technique management but alsowith constraints of economic benefits,society,ecology,environment quality,safe mining and sustainable development in the coal mines.(3)The combination model,for the first time,breaks up the closed situation existing for a longtime,under which the government departments of drainage water,water supply and eco-environment protection from geological survey stage to management evaluation work respectively.Economically,it can spare the repeated geological survey and special assessment work done by the three departments and save a lot of funds;technically,one model is made use of to cover the interference and influence each other for different groundwater seepage fields soas to guarantee a high calculating precision of the forecast,the management and the evaluation work.(4)The management scenario presented in the case study is the most ideal and applicable for thetypical sector.This scenario not only makes full use of the effective dewatering advantages of the artificial relief flow wells under the mines and safe stable water supply advantages of the land surface pumping wells,but also pays attention to the disadvantages of low safe guaranty rate for the relief flow wells under the mines for water supply and of large drilling investment for the land surface pumping wells.References1.Investigation team on mine-hydrogeology and engineering geology in the Ministry ofGeology and Mineral Resources.Investigation Report on Karst-water-filling Mines(inChinese).Beijing:Geological Publishing House,19962.Liu Qiren,Lin Pengqi,Y u Pei,Investigation comments on mine-hydrogeological conditionsfor national karst-water-filling mines,Journal of Hydrogeology and Engineering Geology(in Chinese),19793.Wang Mengyu,Technology development on preventing and curing mine water in coalmines in foreign countries,Science and Technology in Coal(in 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土木工程给水排水英文文献及翻译-英语论文土木工程给水排水英文文献及翻译Building drainage of water-saving techniquesWith people's quality of life,the quality and quantity of water are constantly expanding. Implement sustainable water use and protection of water resources from destruction. And access to healthy water, recycling of water, has become the government and the broad masses of the people the focus of attention. All this gave to the construction of drainage works on the design of the many new requirements, water supply advanced technology of the urgent need to accelerate the pace. This paper will explore more of the building for drainage of water-saving technology; we hope to arouse the awareness of water conservation to build water-saving city efforts.Construction of a water-saving project, in addition to the water saving should formulate laws and regulations to strengthen the management and day-to-day publicity and education use price leverage to promote water conservation work, but also take effective measures, to ensure that the construction of water-saving work carried out in-depth and comprehensive. We are aware that the water supply network's coverage, the extension of transmission mains and the construction of the building because arisingfrom the difference in height, will be used to increase the water pressure before the end of ways to protect the most disadvantaged water points will be adequate water supply, This will be a large number of regional supply of high pressure water supply is. Therefore accessories before the water hydrostatic head greater than outflow, the flow was greater than the rated flow capacity. Beyond the rated flow capacity of that part of the normal flow did not have the use efficiency is a waste of water. As a result of this water is being wasted is not easy to detect and understand, it could be called a "stealth" wasting water.It has been in a different type of floor, the building 67 water distribution points so the overpressure from the measured flow analysis, Statistical results are 55% of the iron spiral movements - taps (hereinafter referred to as "ordinary water") and 61% of the ceramic valve - leading the flow of water-saving more than their rated flow, the super-flow pressure from the state. Two endings the largest flow out of the rated flow capacity of about three times [1]. This shows that in our existing buildings, water supply system overpressure out-flow phenomenon is widespread and it is a fairly serious. In distribution point pressure As overpressure flow out of the "invisible" water is not wasted paid enough attention to, So in our existing "building water supply and drainage design" and "construction water supply and drainage design GBJ15-20 00 draft "(hereinafter referred to as" draft "), although the wateraccessories and home support the greatest pressure certain restrictive provisions in [2], but this is only to prevent water from the high pressure parts will lead to damage to the point of consideration, not prevent excess pressure from the out-flow point of view, the pressure is too lenient restrictions on the flow overpressure no fundamental role. Therefore, in accordance with the water supply system overpressure flow from the actual situation, the pressure on the water supply system to make reasonable limit.1.2 measures taken decompressionWater supply system in a reasonable allocation of decompression device is to control pressure within the limits required to reduce excess pressure from the flow of technical support.1.2.1 Jangled nervesRelief valve is a good decompression device, can be divided into proportional (lower left) of direct action and the type (Photo) The former is based on the ratio of the area to determine the proportion of decompression, which can be set under pressure prior decompression, When the water-stop water, you can also be controlling the vacuum tube pressure is not increased, Decompression can achieve dynamic can achieve static decompression.1.2.2 Decompression orifice and conserving Cypriots1106土木工程给水排水英文文献及翻译Orifice decompression compared with jangled nerves example, the system is relatively simple, less investment, easy management. The practice of some units, water-saving effects are fairly obvious, If Shanghai Jiao tong University in the school bathroom water pipe installation aperture of 5 mm orifice, water-saving about 43%. But decompression orifice only by the dynamic pressure, static pressure can be reduced and the pressure downstream with the upstream pressure and the flow is changed, is not stable enough. In addition, the vacuum orifice plug easy. In better water quality and water pressure more stable, by using [3]. Cutting expenditure and the role of Cypriot advantages and decompression orifice basically are the same. Suitable for the small diameter and accessories installed to use [3].1.3 adopt water-saving leadingA trial showed that the leading Practical water-saving taps and the general state of the full, flow out of the former than the latter out of the flow. That is the same pressure, the leading water conservation has good water saving, water-saving volume in 20% ~ 30% between. And the higher the pressure ordinary tap water from the larger, water-saving is leading the greater the volume of water-saving. Therefore, should the building (especially in the standard water pressure in water distribution points) leading installation of water-saving, reduce water wastage. In 1999 theMinistry of Construction, State Economic and Trade Commission, State Bureau of Building materials apparatuses jointly issued a document "on the elimination of residential buildings behind the products notified" require large and medium-sized cities in new residential prohibit the use of helical-style cast iron nozzle movements, actively adopt "ceramic cartridge faucets" and "common faucet technical conditions of the ceramic cartridge faucets [4]. Since the main building of our school building earlier in the toilet faucet is still an ordinary spiral movement - iron taps. We have often seen leading loosening and tightening the leading difficulty caused by the leakage phenomenon. In fact, there is such a faucet overpressure caused by the "invisible" huge waste of water. Schools should arouse the concern of the relevant departments, from the long-term interests for the use of water-saving new leader, reduce unnecessary losses.2 vigorously develop the construction of water facilities, "watercourse." As the name suggests is not delivered on the waterways clean water is not sullied by sewage contamination. Residents put a wash, bathing, washing clothes and other water washing and flushing water together, after CO., filtration and disinfection, Sterilization, which imported waterway network, for toilet flushing, washing cars, and pouring green, onto the road and other non-drinking purposes. China therefore waterway is also known as miscellaneous water Road. With a watercourse which cubic metersof water, equivalent to the use of one cubic meters of clean water, emit less nearly a cubic meter of sewage and kill two birds with one stone. Water-saving achieved nearly 50% [3]. Therefore, the channel has many of the world's water shortage in cities used extensively.2.1 full use washing wastewater and other quality miscellaneous drainage The existing water facilities built in most hotels, colleges, and the basic source for the bathroom bathing wastewater. For some small units, smaller than bathing wastewater, and discharge time is too concentrated, Water facilities are not stable and adequate source of water. And washing with water wastewater, the use of time more evenly, water treatment and the advantages of relatively good, as a water source, to be fully exploited.2.2 Develop and implement as soon as possible the return to the new water quality standardsThe current construction of water reused implementation of the existing “life miscellaneous water quality standards.” The total coli form standards and the requirements of "sanitary standard for drinking water," the same, compared to the developed countries and the Chinese water standards apply to the swim-minus III also strict standards. This has led to two problems: First, many of the existing water works is less than the standard; 2 are fulfilled with a certain degree of difficulty, improvethe water project investment and processing cost. So should develop appropriate indicators of the value of water works to promote the spread土木工程给水排水英文文献及翻译and popularize. Water Saving water is not limiting, or even prevents the water. But reasonable people to water, efficient use of water and not waste. As long as we pay attention to fit the family's bad habits, we will be able to water-saving around 70% [3]. Water and waste a lot of the habits, such as: flush toilets single wash cigarette butts and broken fine waste; to access a cup of cold water. Many people will not venting water; spend the potatoes, carrots after peeling, washing or after the optional vegetables; when the water stopped (open access customers, answer the phone, change TV channels), not turning off the tap; During the suspension, forget turning off the tap; toilets, wash, brush, let the water has been flowing; Before sleep, go out, do not check the faucet; equipment leaks, not promptly repaired. From the following table, we can see in many parts of life as long as we interested to note that the conservation of water is very impressive.3 to promote the use of water-saving devicesIn addition to the family of water-saving attention to cultivate good habits of water, using water-saving devices is very important and also the most effective. Some people prefer laissez-faire, but also refusedto replace water-saving devices, in fact, so much water is a long time down the uneconomical. Thus vigorously promote the use of water-saving devices is the construction of water-saving important ways and means.3.1Water-saving taps3.1.1 Water Saving leading CeramicsCurrently most of the water-saving taps used Ceramics taps. Such taps compared with ordinary taps, water was typically up to 20% ~ 30%; and other types of water-saving compared to the leading and cheap [3]. Therefore, in the residential buildings of architectural vigorously promote the use of such water-saving lead. We taught the fifth floor of the dormitory building and are used by such leading.3.1.2 Closed since delay tapsSince the delay in the water taps closed after a certain time, shut down automatically to avoid Changliushui phenomenon. Water timing to be in a certain range adjustment, both for the convenience of Health has complied with the water-saving requirements suitable for washing in public places with.3.1.3 Photoelectric controlled tapsClosed since the delay of water-saving taps but water while fixed time and meet the different requirements of the use of the object. Photoelectric controlled taps will be able to overcome the above drawbacks, such as the latest one of the type of infrared device control wash, Thefirst installation will be self-inspection of the device in front of or below the fixed reflectors (for example, vanity) and based on the reflectors adjust their distance from work to avoid the past because of automatic water obstacles closer to the front of regular water, Such intelligent device can wash your hands although below action without washing their hands without water. a long time will wash water and do not have long-term can also regularly flush Water Seal failure to avoid a supply shortage ahead of the police [3].3.2The total water-saving flush3.2.1 Use of small volume cisterns commodeChina is promoting the use of water tanks 6 L fecal water-saving devices, and have flushing water to 4.5 L or even less, stood on the stool available. However, we should also pay attention to the drainage system to ensure the normal work of the use of small volume cisterns commode, otherwise they will be brought to plug the pipeline, not a net wash, and other issues. Two respectively flushing cisterns in urine, flushing water for 4 L (or less); Washing stool, Chong stood at 9 L (or less) [3]. (Map is a two-valve I-Yuan annually to the water tanks, to open the stool below the drain urine when opened above the drain Pictured left is the two-block cisterns switch several forms) Israel's construction regulations require all new buildings to install two respectively wash cisterns. China should also vigorously promoted two respectively cisterns, because one day, thenumber is far higher than the urine stool frequency. To three homes as an example, per person per day for a meeting of feces, urine four times and the use of existing water tanks L 9, day to 135 L of water; 6 L of water use, 90 L of water a day;土木工程给水排水英文文献及翻译and the use of cisterns two respectively, 75 L of water a day, can be seen using two respectively cisterns 9 L 6 L than using more water-saving cisterns [3]. 6 L Yuan annually to the use of water-saving cisterns better results. The use of tanks in two trances another advantage is not right and the replacement of the total drainage system to carry out reform therefore particularly applicable to existing buildings the total replacement of water tanks.3.2.2-washing UrinalThe United States launched the Urinal-washing, which is not water, the stench from the toilets without using utensils, In fact, only in one end Urinal add special "trap" devices, but because the economic, health, water effectively, So popular station.3.2.3Photoelectric control UrinalUrinal photoelectric controls in a number of public buildings installations.3.2.4 Delayed flushing valve closedIt is the use of guide-work principle, water officials directly connected with the water pressure high enough circumstances, can protect the instantaneous flushing commode needs to replace tanks and accessories, installation is simple and easy to use, health, low prices, Water-saving effect of the obvious characteristics [3]. We carpentry center is used for such cleaning.3.3 in hot water systems installed in various forms of water-saving devicesIf installed in public bathrooms limited flow orifice, in the cold, hot water imported pressure balance between the installation of equipment; Installation of low-flow plumbing. Inflatable hot water thermostat and cooling, hot water mixed hydrants.3.4 to further develop various forms of water-saving devices3.4.1 Development of different water taps outSome countries, in different places with different water out of taps, Singapore provides water for washing vegetables pots 6 L / min, shower water 9 L / min; China's Taiwan Province launched the spray-wash special taps, the flow was 1 L / min. In China, various taps most of the rated flow capacity of 0.2 L / s, that is 12 L / min, excessive [4]. Therefore be reasonable to develop taps the rated flow, and gradually installed in different places different from water taps.3.4.2 Vacuum water-saving techniquesTo ensure that sanitary ware and sewer cleaning effect of vacuum technology can be applied to drainage works Most of the air instead of using water, relying on the vacuum of high-speed gas-water mixture, and rapid disposal of the sewage, dirt-gully clean and save water and drain away the effects of dirty air. A complete vacuum drainage system, including: vacuum valve and with a magnitude of suction devices occupants, the closed aqueduct, vacuum collection containers. Vacuum pumps, control equipment and channels and so on. Together with the vacuum generated 40 ~ 5min the negative pressure of sewage pumped to the collection containers, then will collect sewage pump effluent into the municipal sewer. Different types of construction in the use of vacuum technology, the average water-saving exceed 40%. The use of the office building water-saving will rate-70% [2].3.4.3 Development zone leading to the wash waterIn Japan, many families use with the leading water wash, wash all the wastewater into water tanks for back flushing. If the water tank, they can directly turn on the water faucet open. Irrigation water use, it can not only save water but also reduce the costs. At present, the water in China has sales.土木工程给水排水英文文献及翻译随着人民生活质量的提高,对供水量和质的要求正不断扩展.同时实施水的可持续利用和保护,使水资源不受破坏,并能进入良性的水质、水量再生循环,也已成为政府和广大人民群众关注的焦点。
Short and Long Term Advantage roof drainage design performance Decade has witnessed great changes in the design of the roof drainage system recently, particularly, siphon rainwater drainage system has been gradually improved, and there is likely to be the key application. At the same time these changes, urban drainage system design has undergone tremendous changes, because the scope of a wider urban drainage system design for sustainable development, as well as people for climate change flooding more attention. The main contents of this article is how to design roof drainage systems and make a good performance. Special attention is how to get rid of bad habits already formed the design, but also need to consider innovative roof drainage system, such as green roofs and rainwater harvesting systems.Practical application: In the past few years, the design of the roof rainwater drainage system has undergone tremendous changes. On large buildings, siphon rainwater drainage technology has been very common, as well as green roofs because it is conducive to green development, being more and more applications. Taking into account the ongoing research, this article focuses on how to effectively design a variety of roof rainwater drainage system, and make it achieve the desired design effect.1. IntroductionIn the past decade, the city and the water drainage system design has been widely accepted thinking about sustainable urban drainage system, or the optimal management direction. The main principles of the design of these systems is both a local level in line with the quality of development, but also to create some economic benefits for the investors. This principle has led to the development of new changes in the sump. Although the application of such a device is gradually reduced, but the urban environment relatively high demand areas still require 100% waterproof and rapid drainage, such as the roof. Typically roof drainage system in the design, construction and maintenance has not been given due attention. Although the drainage system investment costs account for only a small portion of the total construction investment, but not able to judge the loss caused by poor design.There are two different forms of roof drainage system design methods, namely the traditional and siphon method. Traditional systems rely on atmospheric pressure work, the drive ram affected sink flow depth. Therefore, the conventional roof drainage systems require a relatively large diameter vertical drop tube, prior to discharge, all devices must be connected to the groundwater collection pipe network. In contrast, siphonic roof drainage pipe systems are generally designed to full flow (turbulent flow means that require less exhaust pipe), which will form a negative pressure, the larger the higher flow rate and pressure head. Typically siphon system requires less down pipe work under negative pressure to the water distribution network can mean higher altitude work, thereby reducing the amount of underground pipe network.Both systems consists of three parts: the roof, rainwater collection pipes, pipe network.All of these elements are able to change the water pressure distribution system.This section focuses on the role and performance of each part. Due to the principle of siphon system has not been well understood, resulting argument is relatively small, this article will highlight siphon system.2. RoofThe roof is usually designed by the architect, designer and not by the drainage design. There are three main roof.2.1 Flat roofFlat roofs are used in industrial buildings less rainfall regions and countries. This roof is not completely flat, but lower than the minimum roof slope may require. For example, the United Kingdom require maximum slope of 10 °. Setting minimum slope in order to avoid any unnecessary water.Despite the flat roof if it is not properly maintained will have more problems, but it will reduce the dead zone within the building, and the ratio of sloping roofs in favor of indoor air.2.2 sloping roofsMost residential and commercial buildings are pitched roof, inclined roof is the biggest advantage can quickly drain, thereby reducing leakage. In temperate regions, we need to consider carrying roof snow load. Once it rains, rainfall through the sloping roofs can be determined by calculation. When rainfall data can be used, you can use the kinematic theory to solve such problems.2.3 green roof (flat or inclined)It can prove roof is the oldest green roofs, including rainfall can reduce or disperse roof planted with plants. It can be planted with trees and shrubs roof garden, it can also be a vegetated roof light carpet. Wherein the latter technique has been widely used. Some of these applications tend to focus on aesthetic requirements and are often used in green development. Since the aesthetic requirements and pressure requirements, as well as green roofs thermal insulation function, reduce the heat island effect, silencer effect, extend the life of the roof.Green roofs in Germany, the most widely used, followed in North America, but to consider the impact on the aesthetics. Germany is by far the most experienced countries in the 19th century have practical application, then as an alternative to reduce the risk of fire tar roof an option in urban areas. Germany is currently the main research question on the cultivation of other issues to consider smaller cities. A study from 1987 to 1989, was found packed with 70 mm thick green roof can be reduced by 60% -80% of heat loss. In a Canadian work computer model based on the roof indicates that as long as the sump, the area can reach 70% of the roof area can be reduced by 60 percent in one year, the same model was also used for artificial rainfall, which the results indicate that rainfall in the catchment season helps to drain away rainwater.However, none of these studies show that green roofs can play a useful role in the rainfall season, or how high collection efficiency of water supply. The United States did some tests, as long as the green roofs regular watering, can reduce 65 percent of the runoff in a rainfall. America's most authoritative green roof guidelines by the New Jersey state environmental agencies promulgated. The mainprinciple is to solve the structural problems of light, and how can the normal drainage after two years.Rainfall period is based on the probability of failure is determined. The system is typically based on rainfall during rainstorms two minutes, two minutes, have a choice. Although this model will get more traffic, but there is no other better alternative. Studies have shown that the traditional model is applied to study green roofs are premature.Loss factor than traditional roof records should be small, about 98.7%. Peak flow will be reduced, although not penetrate, the surface roughness but also have a significant impact.Concentrated rainfall than two minutes for a long time, especially for large roof areas, such as public buildings, commercial buildings, industrial buildings.Urban drainage design should also consider other factors, for a complex system, a green roof in a rain is not enough. Water flow duration curve shows a longer than traditional systems. And two independent and will affect between is possible, which requires a more precise time period.3. Rainwater CollectorBasic requirements rainwater collector is designed to be able to accommodate rainfall rainstorms. Although it is possible to make a slightly inclined roof drainage purposes, but the nature of the construction industry and building settlement will become flat roof Typically, the tank is placed in a horizontal, sectional view of the water is outwardly inclined, which the role of hydrostatic.3.1 drain outletAnalyzing rainwater collector has sufficient volume is the key to the sump outlet external setting conditions. Also affect the flow rate into the storm water drainage system piping, but also affect the depth of the water catchment. Although the depth of the sump will not bring any particular problems, but too deep can cause excessive sump.Numerous studies in the 1980s showed that the flow of conventional roof drainage system outlet can be divided into two cases. It depends on the size of the depth and size of the outlet. When the water depth is less than half the diameter of the outlet, the flow of the first type, and the outlet of the flow can be calculated by an appropriate equation; water depth increases, exports are slowly clogging the flow will become another form forms, at the same time, the flow of exports can be obtained through other equations. While conventional roof drainage systems are designed to be free-draining, but may cause limitations encountered in the design of the flow is not free. In this case, it will require additional depth.Siphon roof drainage systems, the outlet is designed to be submerged stream. In this case, the depth of the outlet of the decision is more complicated, because the design of the sump depends on the flow. Recent studies have shown that conventional roof drainage systems use a variety of non-standard catchment, their depth and height, bigger than the diameter of the outlet. This will eventually result in a siphon effect. For a given catchment, the flow depends on the starting end of the drop tube diameter. A similar phenomenon has also been used to study the standardcatchment, in these circumstances, only limited siphon action occurs within relatively close distance from the exit.3.2 tank flow classificationIn the complex flow sump outlet flow classification, can be seen from Table 2a, the flow will be uniform layering, regardless of whether the same inlet flow. Table 2b and 2c show, export distribution will greatly influence the flow.When the outlet is not a free jet, sump outlet complex flow classification is difficult to describe. Because each catchment tank pressures are likely to be merged. For example, the siphon tube system design point is at near full jet outlet flow classification depends on the energy loss of each branch.3.3 hydrostatic sectionalSump shape of the water surface in the canal can be classified according to the flow equation. In most cases, a low flow rate means that there is less friction loss, if exports are free jet, the friction loss is negligible cross-section through the hydrostatic equation 1 to determine the horizontal distance.Where Q-- flow (m3 / s)T- surface width (m)g- acceleration of gravity (m / s2)F- flow area (m2)Equation 1 can not be ignored when the friction required to correct (or very long pipe velocity is large), or not a free jet.3.4 The current design methodsThe previous discussion has highlighted the main factors that should be considered with sink design. However, without the help of a certain number of models, computing hydrostatic sectional roof drainage system, the volume of the sump is possible. This large commercial and manufacturing industry, is a development opportunity, you can merge several kilometers of water routes. Thus, the conventional drainage system sump design methods are mainly based on experience, and assume that exports are free jet.Sump location in the building, it may cause the example to fail.Different interface sumpExcept in the case cited above, but also allows designers to use empirical data.3.5 Digital ModelLarge number of digital models can be used to accurately describe the flow of any form of catchment tank, regardless of whether the roof flows stable. An example of this model is a combination of roof space model. This model enables users to classify different aspects of the data indicated, includes: details of the rains, the roof surface drainage and other details. Kinematics have also been used to study rainwater tank to flow from the research collection. A typical method is based on open system to solve a basic problem of spatial mobility. This model automatically resolve the sump outlet flow situation, but also to deal with the case of free jet can also be simulated space limited mobility and submerged discharge. Output values include depth and flow rate.Currently, the model is essentially just a variety of research tools, but alsothrough practical engineering test. However, we should face up to the various role models.4 pipe systems groupComposition in the form and scope of the tube group determines the roof drainage system relies mainly on the traditional system or siphon action.4.1 Traditional stormwater systemsConventional roof drainage systems, the ground plane is generally vertical pipe-line network, connected to the sump outlet and underground drainage systems, critical systems as well as compensating tube. It should be emphasized that the angle bet ween the ground and the compensating tube is less than 10 °. Capacity of the entire system relies mainly on the outlet tube instead of down.Flow vertical tube is usually free-flowing, full of only 33%, the efficiency depends on the excess length of the tube. If the drop tube long enough (typically greater than 5m), there may be an annular flow. Similarly, under normal circumstances flow compensation pipe is free-flowing, full of up to 70%. Such designed process both for the design, various equations can also be used.4.2 Siphon roof drainage systemIn contrast with the traditional drainage systems, Siphon roof drainage system relies on air flow outside the system, and the tube is full pipe flow stream.The designs are usually made on the assumption that the design of heavy rain, the system can quickly siphon discharge rainwater. This assumption allows the application of hydrostatic siphon system theory. Often used steady flow energy equation. While this approach ignores the small amount of energy loss at the entrance, but after the experiment showed that there are still conducive to practical use.However, steady-state design methods in the siphon system is exposed to rain when the system does not meet the standard requirements or changes in rainfall intensity is large is not applied. In the first case, there will be some mixing of air quality, annular flow occurs. These problems are not integrated in the system when more serious. Because usually designed rains are common, it is clear now design methodology over time may not apply to siphon system. This is a major disadvantage, because the design of the main problem is the noise and vibration problems.Despite the disadvantages of the prior design approach, but a lot of the world's very few engineering failure reports. When a failure occurs, most likely for the following reasons:An incorrect understanding of the operation pointsSubstandard materials listInstallation defectsMaintenance mismanagementTo overcome these disadvantages, we have recently launched a series of research projects, to discuss the siphon system, and the development of digital models. From this work we learn a lot.In contrast with conventional design methods of some assumptions, siphon system mainly has the following aspects:1) non-flow system of full flow2) levels of certain pipe-flowing full pipe flow3) full pipe flow downstream propagation through a vertical pipe, riser, etc.4) the inner tube flow occurs over the vertical section, the system to reduce the pressure5) downward tube is full pipe flow, there will be air lock6) appears completely siphon action until well into the air system is lower thana certain levelTable 4a column data indicate that below the design point, the system will siphon unstable flow, depth of the water collecting tank is insufficient to maintain the siphon action. Table 4b show that the unsteady flow in siphon system when it will appear.Table 5 lists the data output of a digital model. It can be seen that the model can accurately describe the siphon action, siphon and steady state, the data also show that the model can accurately describe the complex siphon action.5 ConclusionThis article has illustrated the critical roof drainage systems, but these are often overlooked in the urban drainage system design. This article also shows that the design process is a complex process, rely mainly on the performance of exports. The following conclusions are based on the design summed up:1) Run depend on three interacting parts: the roof, sump, water pipes2) Green roofs can reduce traffic and beautify the city3) the export performance of the system is essential4) siphon drainage system have a greater advantage in large-scale projects, but must be considered high maintenance costs5) Design siphon drainage system should consider additional capacity and operational issuesAlthough the green roof is a more attractive option, but the traditional roof of a building in the country will continue to dominate. Green roofs will be gradually developed, and gradually been widely accepted. Similarly, the roof drainage system shown effective that it will continue to play a huge role in the commercial building drainage systems.Roof drainage system of the greatest threats from climate change, existing systems tend to be not simply aging; rainfall patterns of change will result in inefficient operation, self-cleaning rate will be reduced. Changes in wind speed and the roof will also accelerate the aging of the roof, it is necessary to carry out maintenance. Taking into account the climate change, the increase in materials, roof collected rainwater will be more extensive. Currently, the amount of rain around the globe per person per day 7-300 liters in the UK, with an average consumption of 145L / h / d, of which only about one liter is used by people, about 30 per cent of the toilet, study shows If water shortage, rainwater collected on the roof of developed and developing countries are recommended approach.屋顶排水设计性能的近期与远期优势最近十年见证了屋顶排水系统设计方面的巨大变化,特别的是,虹吸雨水排水系统已经得到逐步改善,并且有可能得到重点应用。
英文翻译院(系)环境与市政工程专业班级给水排水工程1001班姓名李倩昱学号100320115指导教师王俊萍2014年 04月 18日The effect of rainwater storage tanks on design stormsFrom Urban WaterG. Vaes *, J. Berlamont AbstractThe effect of source control measures on the design of combined sewer systems can in most cases only be correctly assessed using the intrinsic temporal rainfall variability, because long antecedent periods can have an important influence. A conceptual model was built to assess the effect of rainwater tanks on the rainfall runoff using long term historical rainfall series. The outflow of the rainwater tank model is converted to equivalent rainfall series. Based on intensity/duration /frequency-relationships (IDF-relationships) for this equivalent flattened rainfall, modified design storms are developed. ○C2001 Elsevier Science Ltd. All rights reserved.Keywords: Design storm; Intensity/duration/frequency-relationships; Rainwater;Source control; Storage tanks1. IntroductionThe driving force behind the behaviour of many hydraulic structures and systems is the rainfall input. In order to simplify design calculations and limit simulation time, representative single storm events are often used. In Flanders, standard design storms are used for the design of combined sewer systems, based on intensity/duration/frequency-relationships (IDF-relationships) (Vaes, 1999). These design storms are called `composite' storms (Fig. 1), because for one return period all storm durations are included in one storm [comparable with the well-known Chicago-storms (Keifer & Chu, 1957)].However, the variability of the rainfall is high. A comparison between the simulation results (flow, water depth, etc. in hydrologic/hydraulic systems) obtained with continuous simulations and simulations with design storms indicate that significant differences may be found for the probability of an event when the intrinsic variability of the rainfall is neglected (Dahl, Harremoes, & Jacobsen, 1996; Vaes, 1999). The differences will be small for systems, which behave linearly, because the immediate rainfall determines the peak flow and maximum water levels. When the systems behaves more as `capacitive' systems (i.e., where the storage becomes an important parameter), the differences will be larger. A capacitive system has a `memory' that is influenced by the antecedent rainfall. Often combined sewer systems have an emptying time, which tends towards 12 h. For source control structures, the emptying time is even larger (weeks or months). If a severe storm occurs within a short period after an earlier storm, the antecedent rainfall may still occupy a large amount of the storage capacity in the combined sewer system or retention structure. The larger the influence of the memory is, the larger the intrinsic variability of the rainfall will influence the simulation results. For example, for a combined sewer system in a flat region with one pump at the downstream end, the throughflow is almost independent of the storage volume. The stored volume in the system is therefore mainly dependent on the inflow. This is also the case for infiltration structures, where the infiltration capacity is only slightly determined bythe storage in the structure and the remaining storage capacity in the structure is therefore mainly a function of the input history.More and more `capacitive' systems have been built in the last years and will still be built in future. Large storage volumes are necessary to retain the rainfall and to attenuate the flow. These storage volumes can be built in the sewer system (on-line storage) or at the combined sewer overflow (off-line storage). However, more and more attention is now going to `source control'. This means that storage is provided in rainwater tanks, infiltration trenches, etc. upstream of the drainage system. For these source control implementations the influencing antecedent rainfall period is even larger than for storage in the combined sewer system. It has been found that source control requires larger storage volumes (relative to the contributing area) than for down-stream storage (Vaes & Berlamont, 1998, 1999); as well found by Herrmann and Schmida (1999). Due to the longer emptying times for upstream storage, the available storage for retention is much smaller. This all amplifies the need to take into account the intrinsic variability of the rainfall for specific design calculations.2. Effect of retention facilities on downstream drainage systemsThe effect of source control on the design of combined sewer systems can in most cases only be correctly assessed using the intrinsic temporal variability, because long antecedent periods can have an important influence. When storage is built in upstream of the combined sewer system (i.e., before the rainwater enters into the sewer pipes), the rainfall input used to simulate the runoff to the sewer system can be preprocessed in order to take into account the effect of the upstream storage.These local source control implementations are easy to model with a simple reservoir model, which can handle continuous long term simulations in a very short computation time. This preprocessed rainfall can then be used to design the downstream drainage systems. This approach can for example be used for rainwater tanks and infiltration trenches. For rainwater tanks the antecedent rainfall up to one month before may have an effect.With the same simple models the optimal design parameters for rainwater tanks can be determined (e.g.,Herrmann& Schmida,1999; Mikkelsen, Adeler, Albrechtsen, & Henze, 1999), which has led to a design graph for rainwater tanks in Flanders asshown in Fig. 2 (Vaes & Berlamont, 1998, 1999). Furthermore, using simple models for the upstream retention structure as well as for the sewer system (Vaes, 1999), the impact of the upstream retention on the combined sewer overflows can be investigated (Herrmann & Schmida, 1999; Vaes,1999; Vaes & Berlamont, 1998, 1999).3. MethodologyTo incorporate the effect of rainwater tanks on the sewer system design, a model was built to assess the effect of a rainwater tank on the historical rainfall series and to incorporate this effect into a modified composite storm.For this, a simple reservoir model is used with a constant outflow equal to the mean rainwater use in the household (Fig. 3). The fraction α of the rainfall that falls on the roof will flow to the rainwater tank. The rest of the rainfall (1-α) that falls on the other impervious areas is drained directly to the combined sewer system. A small rainwater reuse discharge is slowly emptying the rainwater tank as long as there is water available in the tank. This rainwater will flow to the combined sewer system after it has been used. If the tank is full, all the extra water will flow to the combined sewer system.In Fig. 4 an overview of the implemented methodology is shown. The outflowof the rainwater tank model is converted to equivalent rainfall. A reduction coefficient is determined as the ratio of the IDF-relationship for this equivalent flattened rainfall over the corresponding IDF-relationship for the original rainfall series. The original composite storms are corrected with this reduction coefficient, which is (approximately) a linear function of the storm duration. The reason for the use of a reduction coefficient on the original composite storm is that a more elaborate extreme value analysis was performed to create these original composite storms.4. Extreme value estimationAs the rainfall data have a large intrinsic variability, certainly for high return periods, a specific regression is needed, corresponding to the extreme value estimation for the original IDF-relationships. However, the rain-water tank appears to change the type of the extreme value distribution. The very extreme rainfall events are rarely affected by the storage in the rainwater tanks and thus still fit to the original exponential distribution (Willems, 1998). The more frequent rainfall events are affected more by the smoothing caused by the storage in the rainwater tank and evolve to another exponential distribution. The resulting distribution thus containstwo exponential distributions, which gradually fade into each other. This compound exponential distribution can be approximated by a Pareto distribution, at least for interpolation purpose as in this case. A Pareto distribution has a more heavy tail, which means that there is a larger probability for the extreme events. This Pareto distribution leads to a linear relationship between rain-fall intensity i and return period T in a double logarithmic co-ordinate system (a1 and a2are regression constants):log i =a1+a2 log T.The influence of this smoothing is more pronounced for small storm durations and for rainwater tanks with a large retention function. Depending on which regression will give the best correlation, the exponential distribution will be kept or the Pareto distribution will be used. The application of a simple regression will be sufficient in this case, because no extrapolation will be made for return periods higher than the total length of the original rainfall series. In the end, a linear regression will be used on the reduction coefficients as a function of the storm duration, to obtain a monotonous modified composite storm.5. Practical applicationAs many parameters are involved, this methodology has been implemented in a software program, which was called `Rewaput' (`REgenWAterPUT' is the Dutch word for `rainwater storage tank'). The same methodology can be used to incorporate the effect of rainfall runoff models or upstream infiltration trenches into the designstorms. As more and more source control is applied, this approach will certainly lead to better rainfall input for design calculations in the future.Infiltration and retention facilities often behave non-linearly, because the outflow is often very strictly limited. Continuous long term simulations are thus necessary. The implementation of a simple conceptual model for the upstream retention facilities is simple and the simulation of long time series in this conceptual model does not require long calculation times. In this model 27 years of rainfall is incorporated, which is the same series of rainfall that has been used to determine the Flemish composite design storms (period 1967-1993). One set of parameters for the Rewaput model requires only about five seconds of calculation time on a Pentium III 733 MHz computer. If the parameters vary over a specific catchment, the parameter distributions can be discretised and several sets of parameters can be taken into account. In this case the discretisation step, the deviation on the parameters and the number of varying parameters determine the number of calculations, which have to be performed. In the model Rewaput, a triangular distribution is implemented to approximate the stochastic character of the storage volume and the water consumption (i.e., variation over a catchment) (Fig. 5). For each variation within this triangular distribution the effect is multiplied by the weight corresponding to the parameter distribution in order to calculate the global effect. Using two stochastic parameters the calculation time quadratically increases. To reduce the calculation time the discretisation step has to be chosen taking into account the deviation on the parameters.6. ResultsAlthough the storage in rainwater tanks and infiltration facilities is not always completely available during severe rainfall (i.e. because the facility is already filled with the antecedent rainfall), this kind of upstream retention facility still can have a large influence on the rainfall runoff to the sewer system. It has been shown that well-designed rainwater tanks can even significantly reduce the peak flow in sewer systems, if they are installed on a sufficiently large scale. In Fig. 6, an example is shown of what the possible effect of rainwater tanks on a design storm can be. In this case, it is assumed that rainwater tanks of 5000 l per 100 m2 roof area are built for 30% of the total impervious area and that 100 l per day and per 100 m2roof arearainwater is consumed. This almost reduces the peak of the composite storm for 5 years to the value of the composite storm for 1 year. It is impossible to predict this effect using a single storm design approach.7. ConclusionsThis methodology shows the large impact of source control facilities on design rainfall for the downstream drainage systems. Furthermore, it shows that it is important to incorporate the real variability of the rainfall in order to obtain an accurate estimation of the effect of upstream retention. In order to limit the calculation times this can be successfully applied using simple models.This methodology can also be used to incorporate the effect of a non-linear surface runoff model or to simulate the effect of infiltration facilities, even when they are influenced by the ground water table. Currently, in Flanders, for sewer system design a fixed runoff coefficient of 0.8 is used for the impervious area. When (long term) measurements are available, a more realistic runoff model (i.e., a more capacitive (depression storage based) runoff model) can be calibrated. This can then be included in the design calculations by routing long rainfall series through the simple conceptual runoff model and incorporate the effect in the design storms. The same is valid for infiltration facilities and runoff from pervious areas. Simple conceptual models can be used to reshape the design storms, so that simple design storms are obtained without neglecting the effect of the rainfall variability on theupstream retention facilities.AcknowledgementsThe authors are grateful to the Belgian Royal Meteorological Institute that made the rainfall series available in digitised form for research purposes and to the Flemish water company Aquafin for their support to this research.References[1] Herrmann, T., & Schmida, U. (1999). Rainwater utilisation in Germany:efficiency, dimensioning, hydraulic and environmental aspects. Urban Water, 1(4), 307-316.[2] Keifer, C. J., & Chu, H. H. (1957). Synthetic storm pattern for drainage design.Journal of Hydraulic Div., 83(4).[3] Mikkelsen, P. S., Adeler, O. F., Albrechtsen, H.-J., & Henze, M. (1999).Collected rainfall as a water source in Danish households -what is the potential and what are the costs? Water Science Technology, 39(5), 49-56.[4] Vaes, G. (1999). The influence of rainfall and model simplification on the designof combined sewer systems. Ph.D thesis. University of Leuven, Belgium.[5] Vaes, G., & Berlamont, J. (1998). Optimization of the reuse of rainwater. InProceedings of the international WIMEK congress on options for closed water systems, Wageningen, Netherlands.[6] Vaes, G., & Berlamont, J. (1999). The impact of rainwater reuse on CSOemissions. Water Science Technology, 39(5), 57-64.[7] Willems, P. (1998). Hydrological applications of extreme value analysis. InInternational conference on hydrology in a changing environment, Exeter, UK.雨水储存槽对暴雨设计的影响选自《城镇水网》作者:乔.沃思;简.伯夏娜摘要在大多数情况下设计联合排水系统,水量控制影响能正确评估天然的暂时性降雨,因为长时间的前期降雨会产生极大的影响,建立一个概念性的模型能够评估雨水储存槽系统能在长期历史降水时期的降雨量,雨水槽系统模型将水流量变为平均流出量。
中英文对照的建筑给排水设计说明MECHANICAL PRELIMINARY DESIGN REPORTSTADIUM1.给排水设计饮用水和污水1.Sanitary DesignWater and sewage water.设计基础- 甲方提供的设计任务书和市政管网综合图- 建筑专业提供的条件图- 国家现行的设计规范及有关规定设计简章.Design basesDesign Brief and Municipal integrated network drawing offered by the client. Condition drawings from architectural discipline.Current national design codes and related stipulations2. 给水系统通过一根DN200的进水管将水引入.水表安装在进水管上,离红线1米处.供水管在红线内连成环路管网,并接到供应楼的消防水池和给排水水池.由环路管网向必需的室外消火栓和绿化带的喷淋器供水.2. Water supply systemFor water supply of this project, DN200 water intake pipes are led in. Water meters are installed on the intake pipes 1.0 m away from the red line. The water supply pipes are connected into loop networks in the red line and then led to the fire pool and sanitary water pool in the supply buildings respectively. Necessary number of outdoor hydrants and sprinklers for green area will be provided on the loop networks. 设计范围包括红线内的饮用水,污水,雨水,建筑消防.Design scopeDesign scope of this project includes water, sewage water, rainwater, fire-protection in the building, and water and sewage water within the red line. 给排水水池与消防水池分开,容量为100m3 .体操馆供水管埋地敷设.Sanitary water pool is separated from fire water pool, volume of sanitary water pool is 100m3. Water supply pipes for the stadium will be laid in the earth.3.用水量标准- 体育馆: 15升/顾客·日 K=2.0- 宾馆: 150升/人·日 K=2.0- 餐厅: 50升/顾客·日 K=2.0- 工作人员: 25升/人·日 K=2.0- 地面冲洗用水: 3升/m2日- 冷却塔补水量:按用水量的2%计- 未预见水量: 按日用水量20%计- 消防用水:消火栓:室内40升/秒,室外30升/秒,火灾延续时间为3小时;自动喷洒按22升/秒,火灾延续时间为1小时卷帘水幕用水0.5升/秒·米,火灾延续时间为3小时;Water consumption standard- Stadium: 15L/visitor·day K=2.0- Hotel: 150L/visitor·day K=2.0- Restaurant: 50L/customer·day K=2.0- Staff 25L/perso n·day K=2.0- Floor cleaning: 3L/m2·dayMake-up water for cooling tower: 2% of theactual cold water consumption.Unforeseen water consumption: 20% of the dailywater consumption.Water for fire protectionHydrant: 40L/s indoor, 30L/s outdoor, fireduration time is 3h;Sprinkler: 22L/s, fire duration time is 1h;Drencher for rolling shutter: 0.5L/s·m, fire duration time is 3h;在适当的位置设置饮用水机,在主进口为残障人设置两个饮用水机.为此饮用水系统安装循环泵.机房设在地下室的水除了机房.当饮用水机不被使用时,应排空,以免水质腐败.在客房和餐厅内设置电热水器,同时亦为热水供应设置循环泵.在更衣间旁设置电热水器,为淋浴和洗盥供应热水.为楼板清洁安装一定数量的水龙头.Some suitable places are supplied with portable water drinking units, two drinking units for disable people are provided at main entrances, for this portable water system, circulating pumps are adopted, the equipment room is located in water treatment center in the basement. When there is no use, portable water will be drained completely to avoid deterioration.Electric water heaters are installed in guest rooms and restaurant, also hot watercirculating pumps will be provided for supplying hot water.Electric water heaters are installed near the changing and clothing rooms for supplying hot water for shower and washing.Certain number of water taps are installed for floor-cleaning.4.用水量最大日用水量:2.200m3/日最大时用水量:220m3/时Water consumption demandMaximum daily water consumption: 2.200m3/dayMaximum hourly water consumption: 220m3/hour却循环系统冷却水循环系统采用机械循环系统.总冷却水用量为460m3/h.在供应楼顶设置三台超低噪音冷却塔(230 m3/h, 2x 115 m3/h).进水温度37Co,出水温度32Co .补充水量9,6 m3/h.补充水由市政供水网直接提供.Cooling water circulation systemThere are cooling water circulation system in this project, cooling water for the refrigerators adopts mechanical circulation system. Total water consumption of cooling towers is 460m3/h. On roof of the supply building there are 3 ultra-low noise cooling towers (230 m3/h, 2x 115 m3/h), inlet temperature of 37Co, outlet temperature of 32Co, with make-up water of 9,6 m3/h. Make-up water of the cooling towers will be supplied directly by the municipal network.在消防泵房内有消火栓泵(一个运行,一个备用),喷淋泵(一个运行,一个备用),卷帘雨淋泵(一个运行,一个备用).用于地下车库的泡沫喷淋设备,如报警阀,泡沫压缩罐,化学药剂泵安装在消防设备中心.30.0m3 消防水箱和消防稳压装置分别安装在车库的四面墙.In the fire water pump room, there are hydrant pumps (one operation, one standby), sprinkler pumps (one operation, one standby) and rolling shutter drencher pumps (one operation, one standby).Fire equipment, which are used for the foam sprinkler system in underground garage, such as fire alarm valves, foam concentrated tank and chemical dosing pump, etc. are provided in fire equipment centers. Four 30.0m3 fire water tanks and fire protection stabilized pressure devices are respectively located at four sides next to the garages.消防用水消火栓:室内按40升/秒,室外按30升/秒,火灾延续时间按3个小时计自动喷洒按22升/秒,火灾延续时间按1小时计卷帘水幕用水量 0.5升/秒·米,火灾延续时间按3个小时计消火栓:室内,室外用水量皆为756m3;自动喷洒用水量为79.2 m3;卷帘水幕用水量为 270m3;一次火灾用水量为1.861,2;Water for fire protectionWater consumption standard for fire protectionHydrant: 40L/s indoor, 30L/s outdoor, fire duration is 3hSprinkler: 22L/s, fire duration is 1hDrencher for rolling shutter: 0.5L/s·m, fire duration is 3hWater consumption for fire protectionHydrant: indoor and outdoor water consumptions are 756m3 respectively Sprinkler: 79.2 m3Drencher for rolling shutter: 270m3Water consumption for one fire: 1.105,2 m3消火栓的布置在整个建筑物内沿墙,沿柱,沿走廊,风塔上及楼梯附近设有必要数量的室内消火栓,消火栓间距小于30米.消火栓管网水平,竖向皆成环状布置,消火栓箱内配有DN65消火栓一支,25米衬胶水龙带一条,φ19毫米喷咀水枪一支,并配消防卷盘(DN25消火栓一支,30米胶管,φ9毫米喷咀水枪一支)且设有可直接启动消火栓泵的按钮;在室内消火栓箱下设有磷酸铵盐手提式灭火器箱.室内消火栓系统在室外设有三组水泵接合器.Hydrant arrangementNecessary number of hydrants are installed indoors along the wall, columns, corridors, and staircases, at intervals of less than 30m. Hydrant networks are connected as a loop both horizontally and vertically. Inside each hydrant box, a DN65 hydrant, a 25m long rubber lined hose, a water nozzle of φ19mm, hose reel (a DN25 hydrant, a 30m long rubber lined hose and a water nozzle ofφ9mm), and a direct starting button for the hydrant pump are provided.Under each indoor hydrant box, a portable ammonium phosphate powder extinguisher box is installed. There are three sets of pump adopters being installed outdoors for the indoor hydrant system.消防系统防水泵房及消防水池供水管DN200在红线内连成环路管网,管网上安装一定数量的消火栓.两根DN200供水管分别引入供应楼内两个消防泵房内的消防水池.消防水池总容量不应小于4000m3, 每个为2.000m3.Fire protection systemWater pump room and water pool for fire protectionThe lead-in pipes (DN200) are connected as a loop inside the red line, on the loop, certain number of hydrants are installed.Two water supply pipes (DN200) are led into the fire water pools at each fire water pump room in supplybuilding. In consideration of the importance of the project, the volume of the fire water pools should be not less than 4000m3, each is 2.000m3.自动喷淋系统自动喷淋系统安装在全建筑范围,除了室外和高于10 米的房间.喷淋泵安装在地下的消防泵房内.报警阀设置在地下的消防泵房内和中间的消防设备中心内,水流显示器设在每个防火分区内.Sprinkler systemSprinkler systems will be provided inside the whole building except outside areas and roomshigher than 10m, with sprinkler pumps installed in the underground fire water pump rooms. Alarming valves installed in underground fire water pump rooms and four fire equipment centers in the middle, water flow indicators are installed by fire compartments.除了安装一个封闭喷淋系统,将为地下车库设置一个泡沫喷淋系统.餐厅内安装93oC启动的自动喷淋头,但在其它房间,仅安装93oC启动的普通和快速反应自动喷淋头.三组泵接合器安装在室外.Besides an enclosed sprinkler system, a foam sprinkler system composed of a proportioning mixer and a foam concentrated tank is provided for the underground garage. Sprinkler actuated at 93oC are provided in the restaurants, but in other rooms, only ordinary sprinklers and fast response sprinklers actuated at 68oC are provided.Three sets of pump adaptors for this system will be installed outdoors.排水系统为排水系统设置污水主立管和特别垂直排气管.排气管与污水管在每层连接,污水排出体操馆.餐厅的污水首先在油脂分离池中处理,然后排入室外排水网.给排水污水将被在化粪池收集和处理,然后排入市政排水管网.化粪池在输送区旁.最大天排水量为870m3/天.9. Drainage systemMain vertical sewage pipes and special vertical vent pipes are provided for the drainage system. The vent pipes are connected with sewage pipe at each floor; sewage water is drained out of stadium. Sewage water in the restaurants and garage are treated in the grease and oil separation tank, and then discharged into the outdoor drainage networks. Sanitary sewage water is collected and treated in the septic tank,then drained into the municipal drainage. The septic tanks are located besides the deliverycircle. Maximum daily drainage amount is 870m3/day.卷帘水幕系统地下车库设置有卷帘水幕系统.水幕泵安装在消防水泵房内,采用开式雨淋头,电动或手动控制.十组泵接合器安装在室外Drencher system for rolling shuttersRolling shutter protected by drenchers are provided for the underground garage, the drencher pumps are installed in the fire water pump rooms, open drencher heads are selected, and are controlled both by electrically and manually. Ten pump adapters will be installed outdoors for this system.地下室内污水设有污水坑,废水设有废水坑,生活污水,废水经潜污泵提升排至室外排水管网,潜污泵的启停皆由磁性浮球控制器的控制.地下汽车库废水设有废水坑,废水经潜污泵提升排至室外,经隔油池处理后排入室外雨水管网.There are cesspits for sewage water and wastewater pits for wastewater in the basement, the sewage and wastewater is sucked up and drained to the outdoor drainage networks by submerged sewage pumps.Operation of the pumps is controlled by the magnetic floating ball controllers. Wastewater pits are provided for the underground garage, wastewater is sucked up and drained to outdoor oil separation tank by submerged sewage pumps, after treated, wastewater is drained to the outdoors rainwater networks.在柴油发电机房,变配电房和通讯设备机房设低压二氧化碳气体灭火系统.Low pressure CO2 extinguisher systems are provided in diesel generator rooms, transformer substations and telecommunication equipment rooms.在本建筑内按"建筑灭火器配置设计规范"在每个消火栓箱下设手提式灭火器箱,箱内设有必要数量的磷酸铵盐手提式灭火器.According to the Code for Design of Extinguisher Disposition in Buildings, portable fire extinguisher box, in which there are necessary number of portable ammonium phosphate powder extinguishers, will be installed under every hydrant box.在每个消防电梯井底旁设有消防排水坑,废水经潜污泵提升排至室外.Fire water drain pit is provided at side of bottom of each fire elevator well, waste water will be sucked up and drained out by the pumps.雨水系统雨水排水屋顶采用压力流排水.雨水设计重现期按P=10年计算,降雨历时为5分钟,暴雨强度公式按Q=998.002(1+0.568lgP)/(t+1.983)0.465计算.沿柱在屋面设置雨水沟.雨水通过雨水沟收集,然后进入雨水头和下排管,然后到室外雨水观察井.10. Rainwater systemPressurized drainage system is adopted for roof rainwater drainage system. Here, return period P=10 years, rainfall duration is 5 minutes, stormwater amount is calculated by the following formula:Q=998.002(1+0.568lgT)/(t+1.983)0.465Rainwater gutters are provided on roof along columns, skylight. Rainwater is collected in the gutter, then to rainwater heads and downpipes, and to the outdoors rainwater inspection wells.11.管材- 生活给水管,冷却塔补水管采用铜管,氩弧焊接.- 直饮水管采用不锈管.- 消火栓管,冷却循环管,水幕管,水泵吸水管采用焊接钢管,焊接.- 自动喷洒水管,雨淋水管采用热镀锌钢管,丝扣连接或卡压连接.-二氧化碳管采用无缝钢管焊接.- 地下车库泡沫喷淋水管采用不锈钢管,卡压连接.Pipe materialCopper pipes connected by argon arc welding are adopted for the sanitary water pipes, make-up water pipes for cooling towers.Stainless stell pipes are adopted for portable water pipes.Welded steel pipes connected by welding are selected for hydrant pipes, cooling circulating pipes, drencher pipes, pump suction pipes.Hot-galvanized steel pipes connected by threads or compression-seizing are selected for sprinkler and deluge sprinler pipes.Seamless steel pipes connected by welding are selected for CO2 pipes. Stainless steel pipes connected by pressed clamp is selected for the pipes of foam sprinklers in the underground garage.当雨水两超出雨水沟设计量时,雨水可沿屋檐自由排放.雨水被收集,然后排入市政集水池. When the amount of rainwater is more than the design value of the gutters, water is discharged naturally along the eaves. Rainwater is collected, and then drained to the municipal catch basins.围绕体育馆的循环池将用于喷洒运动场和作为室外绿化带的储水池.此池将作为一个循环过滤设施,可容水约7.500 m .喷洒压力设备和其它必须的过滤设备安装在供应楼里.The circular senic pool surround stadium will be used for spraying sportsfield andas reservoir for outdoor greening.The pool will be used as a circular filtering facility and will be adopted with a water volume of about 7.500 m .The spray water pressurizing equipment as well as further necessary filtering equipment will be adopted in the supply building.2.0 制冷2.0 Cooling冷源:空调冷负荷(估算):本工程建筑面积共50.000平方米,包括观众区,休息室,更衣室,小会议室,餐厅,办公室和其它附属房.空调设计日峰值冷负荷为2.4MW,设计日总冷负荷为3 kW.Refrigerating sourceCooling load of air conditioning systemTotal floor area for this building is 50,000sqm, which includes spectator areas, lounges, Clothing and changing rooms small meeting rooms, restaurant, office and other auxiliary rooms. Designed dayly peak cooling load is 2,4MW, designed total dayly cooling load is 3kW.每台1200kW制冷机配一台流量为206m3/h离心泵.各配一台备用泵一次泵采用压差旁路控制.通过埋地敷管,向游泳体操馆供应冷冻水.A centrifugal pump with a flow rate of 103m3/h is provided for each 1200kW chiller. One operation pump with a standby corresponds to one chiller.Pressure difference branch control is adopted for primary pumpVia earth laid pipes from supply building to gymnasium chilled water supply will be deliverded.冷源的选择:根据建筑的实际情况,3台制冷机将安装在供应楼内的冷冻机房.设计容量为4800kW. 为了实现能量的效率化使用,设计方案为,1台制冷机的出力为总设计容量的50%.而另2 台.每台出力为总设计容量的25%.冷冻水系统的主要设备包括3台电动制冷机,一级冷冻泵,二级冷冻泵,自动控制阀等等.冷冻水的供/回水温度为-7/ 12°C.Selection of refrigerating sourceAccording to the real condition of the building, 3 chillers are located in the refrigerating plant rooms in the supply building, designed capacity is 2400kW. For actuing in an energy efficient way one chiller about 50% of total capacity (1.200 kW) and two chillers with 25% of total (600 kW each)capacity each are adopted.Main equipment of chilled water system includes 3 electrical chiller, primary cool water pump, secondary chilled water pump and automatic controlled valve, etc. supply/return temperature of the chiller is-7/ 12°C.二次泵系统:根据使用功能,各制冷机房又分成不同的循环支路.二次泵采用变频调速控制.根据负荷侧供回水管的压差,控制水泵的转速.二次泵循环支路的管道采用异程式.Secondary pump system:Each refrigerating plant room is subdivided into different circulation branch loops according to use functions.Variable-frequency speed-regulating control is adopted for secondary pumps. The rotating speed of a water pump is controlled according to the pressure difference between water supply and return pipes.Direct return system is adopted for the pipes of circulating branch of secondary pumps空调冷冻水系统由于本工程占地面积大,功能复杂,有连续使用,也有间歇使用,为了达到运行灵活,节能的目的,空调冷冻水系统采用两管制二次泵系统.Chilled water systemDue to the large occupied area of this project, the complicated functions and the combination of continuous utilization and intermittent utilization, in order to accomplish the purpose of flexible operation and energy saving, the chilled water system is of two-pipe secondary pump system.管材:水管采用焊接钢管及无缝钢管.本工程的风管除土建风道外,均采用镀锌铁皮咬口制作.每节风管之间用法兰连接.Pipe and duct materialsThe water pipes adopt welded steel pipes and seamless steel pipes.Air ducts for this project are made of galvanized sheet steel by seaming except ducts by civil construction. Air ducts are connected together by flanges.一次泵系统:供应楼冷冻机房2400kW制冷机配一台离心泵, 流量为412m3/h.配一台备用泵.Primary pump system:Chiller room supply buildingA centrifugal pump with a flow rate of 412m3/h is provided for 1200kW chiller. Oneoperation pump with a standby corresponds to one chiller.保温材料:空调供,回水管,冷凝水管采用酚醛管壳保温.空调送,回风管以及处理后的新风管采用外贴铝箔的离心玻璃棉板保温.- 管道穿防火墙的空隙处采用岩棉材料等非燃材料填充.Thermal materialsphenolic pipes are adopted for thermal insulation of water supply and return pipes for air conditioning, as well as air-conditioning condensate pipes.Aluminum foil faced glass fiber boards are adopted for thermal insulation of air-conditioning air supply and return ducts as well as fresh air ducts after chillers.Non-flammable material will be selected to fill the interspace in the fire protection wall where the ducts go through.消声与隔振:冷水机组,水泵等设备采用减振台座,弹簧减振器或橡胶减振垫减振降噪.在空调机组,新风机组,通风机的进出口采用涂胶帆布软管连接.- 水泵进出水管上采用可曲挠橡胶接头,使设备振动与配管隔离.Noise reduction and vibration isolationShock absorption bases, spring shock absorbers on rubber shock absorption pads are adopted for equipment, such as water chiller units, pumps, etc to reduce vibration and lower noise.Flexible rubber-coated canvas hoses are adopted far connections of inlets and outlets of air-conditioning units, fresh air handling units and ventilators. Flexible rubber couplings are adopted for the water intake and delivery pipes of the pumps to isolate equipment vibration from their pipes.3.0空调和通风系统3.0 Air Conditioning and Ventilation Systems方案设计范围Scope of schematic design空调设计Air Conditioning Design在体育馆内,一些区域设置空调系统.这些区域划分为:西侧地下二层的贵宾休息室东侧地下二层酒店门廊地下一层的输送区,技术机房,运动员更衣间,医务服务,热身区,裁判区,健身中心,酒店大堂,会议室,厨房,特许区和贵宾大堂混合区.首层的酒店大堂,酒店区,贵宾门廊,急救In the stadium, in some ranges air conditioning systems are used. These ranges subdividethemselves as follows:VIP – Lobby in West of levelel -2Hotel lobby in the east of level –2Delivary Circle, technical Plantrooms, Changingrooms for the athletes, Medical Service and warm up area, Judges Area, Fitness Center, Hotel Lobby, Conferenz, Kitchen and Concession, Vip lobby- Mixed Zone in level -1Hotel lobby, Hotel area, Vip lobby, Vip Area, First aid in 0空调和通风机组设置于靠近地下一层楼梯底部的机防.新风从楼梯底的风室被引入机房而被空调处理器吸入.从此,通过水平和垂直风道送至使用区.用于以上区域的空调机组分为12 台暖通空调机组,具有以下特点The air conditioning and ventilation units for the using ranges are placed in die mechanical plantroom nearby the stairs in the bottom of the stadium in Level -1. The outside air will be brought into the Plantrooms from fresh air chambers under these stairs and let to the air handling units. From here, the will be led via horizontal an vertical duct to the using ranges.The air conditioning units for the ranges specified above will be devided into 12 HV AC- units (drawings) with the following characteristics:以下区域仅设置排风系统:地下二层停车区域地下二层电气机房地下一层卫生间首层卫生间一层卫生间宾馆客房设置分散式风机盘管加新风系统.贵宾室设置风机盘管.For the following ranges, only exhaust air systems are planed:Parking area in Level –2Electrical Plantrooms in Level –2Toilets in Level –1Toilets in Level 0Toilets in Level +1For the guestrooms of the Hotel decentralized Fancoil Units with ourside air connection are planed. The VIP- boxes will be equiped with Fancoil Units.AC1, AC6, AC7, AC12地下一层的附属用房(储存,机房,楼层,观众区 )换气次数 2 – 6 次/小时; 新风100%, 通过螺旋风口送出双风机,全空气系统排风机同时作为机械排烟用AC1, AC6, AC7, AC12Siderooms ( Storage, Plantrooms, Floors, Spectaors area) in Level -1Air Changing rate 2- 4 times/ h; supply via spiral outlets, outdoor air 100% Dual- fan- all- air system.Exhaust air fan is also be used for mechanical removal of smoke.AC 2地下一层的医务服务,热身区,运动员更衣间,裁判区换气次数 2 – 4 次/小时; 新风100%, 通过螺旋风口送出夏季最高室内温度29°C, 相对湿度 65 %冬季最高室内温度 22 –24°C室内发热量:- 照明 20 W/m- 机器 10 W/ m- 人员 50 W/ m双风机,全空气系统排风机同时作为机械排烟用AC 2Medival Service Area, Warm up Area, Changing rooms Athletes, Judges Are in Level- 1Air Changing rate 2- 4 times/ h; supply via spiral outlets, outdoor air 100% Room temperature 29°C max, 65 % humidityin SummerRoomtemperatur 22 –24 °C in WinterIndoor heat loadLighting 20 W/mMachines 10 W/ mPersonnel 50 W/ mDual- fan- all- air system.Exhaust air fan is also be used for mechanical removal of smoke.AC 4地下一层的医务中心,办公室换气次数 4 次/小时; 新风100%, 通过螺旋风口送出最高室内温度29°C, 相对湿度 65 %室内发热量:- 照明 35 W/m- 机器 30 W/ m- 人员 50 W/ m双风机,全空气系统排风机同时作为机械排烟用AC 4Media Center, Offices in Level –1Air Changing rate 4 times/ h; supply via spiral outlets, outdoor air 100% Room temperature 29°C max, 65 % humidityIndoor heat loadLighting 35 W/mMachines 30 W/ mPersonnel 50 W/ mDual- fan- all- air system.Exhaust air fan is also be used for mechanical removal of smoke.AC 3地下二层的贵宾休息室,地下一层的贵宾大堂,混合区,首层的贵宾办公室和贵宾区换气次数 4 次/小时; 新风100%, 通过螺旋风口送出最高室内温度29°C, 相对湿度 65 %室内发热量:- 照明 20 W/m- 机器 10 W/ m- 人员 50 W/ m双风机,全空气系统排风机同时作为机械排烟用AC 3VIP Lobby in Level –2, VIP Lobby, Mixed zone in Level –1, VIP Offices and VIP area in Level 0Air Changing rate 4 times/ h; supply via spiral outlets, outdoor air 100% Room temperature 29°C max, 65 % humidityIndoor heat loadLighting 20 W/mMachines 10 W/ mPersonnel 50 W/ mDual- fan- all- air system.Exhaust air fan is also be used for mechanical removal of smoke.AC 5地下一层的厨房,服务和特许区厨房的换气次数 100m /m 小时,新风100%, 通过螺旋风口送出服务和特许区的换气次2-4数次/小时, 新风100%, 通过螺旋风口送出双风机,全空气系统最高室内温度29°C, 相对湿度 65 %室内发热量:- 照明 35 W/m- 机器 30 W/ m- 人员 80 W/ m双风机,全空气系统排风机同时作为机械排烟用AC 5Kitchen, Service and Concession area in Level -1Air Changing rate 100 m /m h for the Kitchen; supply via spiral outlets, outdoor air 100%Air Changing rate 2-4 times/h for the Service and Concession area; supply via spiral outlets, outdoor air 100%Room temperature 29°C max, 65 % humidityIndoor heat loadLighting 35 W/mMachines 30 W/ mPersonnel 80 W/ mDual- fan- all- air system.Exhaust air fan is also be used for mechanical removal of smokeAC 8地下一层的健身中心,员工更衣间,特许区换气次数 2 – 4 次/小时; 新风100%, 通过螺旋风口送出最高室内温度29°C, 相对湿度 65 %室内发热量:- 照明 35 W/m- 机器 30 W/ m- 人员 80 W/ m双风机,全空气系统排风机同时作为机械排烟用AC 8Fitness Center, Changingrooms Staff, Concessio in Level -1Air Changing rate 2-4 times/h; Fitness Center 6 times/ h; supply via spiral outlets, outdoor air 100%Room temperature 29°C max, 65 % humidityIndoor heat loadLighting 35 W/mMachines 30 W/ mPersonnel 80 W/ mDual- fan- all- air system.Exhaust air fan is also be used for mechanical removal of smokeAC 10地下二层地的宾馆走廊,地下一层的宾馆走廊和餐厅,首层的宾馆区换气次数 4 次/小时; 新风100%, 通过螺旋风口送出最高室内温度29°C, 相对湿度 65 %室内发热量:- 照明 35 W/m- 机器 30 W/ m- 人员 50 W/ m双风机,全空气系统排风机同时作为机械排烟用AC 10可能亦用于人防区的送风.此部分的设计由人防技术设备设计工程师审核.AC 10Hotel Lobby in Level- 2, Hotel Lobby and Restaurant in Level -1, Hotel area in Level 0Air Changing rate 4 times/h; Restaurant 8 times/h;supply via spiral outlets, outdoor air 100%Room temperature 29°C max, 65 % humidityIndoor heat loadLighting 35 W/mMachines 30 W/ mPersonnel 50 W/ mDual- fan- all- air system.Exhaust air fan is also be used for mechanical removal of smoke.The AC- unit No. 10 might also be used as a supply air unit for the shelter. This has to be checked by the engeneers who will plan the technical equipment for the shelter.AC 9通风地下车库:设计一个换气次数 6次/小时的排气排烟通风系统.由地下一层的空调机组送风,送风经过车库顶棚的垂直风口进入水平风道,然后送至各处.输送区:输送区设置一个隧道通风系统.空气通过北侧被吸入建筑物,然后通过轴流风机输送到输送区.空气通过南侧的就近道路排出.VentilationUnderground Garage:For the underground garage an air exhaust an smoke exhaust ventilation system with an air exchange rate of 6 times/h is provided. The supply air for the garage will be delivered from the AC- Units in Level- 1 an brougt into the garage via vertical openings in the ceiling of the garage and distributed over horizontal ducts. Delivery Circle:For the delivery circle a tunnel ventilation system is installed. Air is sucked at the south side of the stadium into the building and transported by axial jet fan through the delivery zone.各功能区的规划包括水平管道和竖井.各区域无异味和污染物的排风将被作为送风送入车库. 剩余的排风和排烟将通过一个地下风道送到供应楼,并通过屋顶排出.排烟内部区域均设置机械排烟.通风系统的管道亦即排烟道. 在空调机房内,烟气通过一条旁通风道送至车库排风机,亦为排烟机(300°/ 30 分).The development of the functional areas is made by horizontal ducts and vertical pits. The exhaust air from ranges which are not smell-loaded or contained pollutants are brought as supply air into the garage.The remaining exhaust air and the removal of smoke exhaust air are led over an underground channel to the supplying building and blown out there over roof. Smoke ExhaustionAll ranges on the inside are exhaustet from smoke mechanically.The duct system of the existing ventilation systems is used. In the HVAC plant rooms, the flue gases are led over a bypass channel to the exhaust air fan for the garage, which have to be designed to be used as smoke- exhaust fan (300°/ 30 min).室内储存和技术房:此区内,设置简单的送排通风系统.卫生间:地下一层和首层的卫生间由临近区域的通风系统供应新风.一层卫生间通过向外开口进风.地下一层卫生间排气排入输送区.首层和一层卫生间将通过独立的排气扇将废气排入在看台下部.Indoor storing and technical plant rooms:For this ranges simple supply- and exhaust ventilationsystem will be installed Toilets:The WCs in level -1 and level 0 are supplied with fresh air by the ventilation systems of the adjacent ranges.The WCs in level +1 receive the fresh air over opening to the outside.The WC in level -1 is aired out separately into the range of the delivary circle. The exhaust air of the WC ranges in level 0 and level +1 will be led by separate exhaust fans into the ranges underneath the grandstand.车库的排气和烟气被加压,通过地下风道送至供应楼,而通过其屋顶排出.停车场有烟雾时,空调机组的送风量是不足的.在这种情况下,新风将通过阀门从新风室(在体育馆底层楼梯下)直接向车库进风.The exhaust air of the garage and the smoke will be pressed through the circularly air duct and then through the underground channel to the supplying building and will there be led over roof into the free.In case that smoke is detected in Parking garage, the supply air from the AC- Units which is normaly used for the supply of the garage is not sufficient.In this case the fresh air will be brought directly into the garage via dampers from the freshair chamber, placed underneath the stairs in the bottom of the stadium. 主送风和回风道均设防火阀. 当温度超过70°C, 防火阀将自动关闭,同时风机停止运行,关闭信号将被传送.自动转换防火阀安装于排风排烟共用系统.Both, the main air supply and return ducts of all AHUs are provided with fire dampers. Then a temperature over 70°C happens, the fire dampers wil l be closed automatically and at the same time the fan stops operation and cut-off signal is transmitted. Automatic changeover fire damper is provided for the system used both return air and smoke exhaust.空调和通风系统的电力供应控制与消防控制中心相连. 当某个防火分区火灾报警, 而且消防中心对此信号经过分析确认后,此防火分区内的通风系统停止运行,而同时排烟系统和加压送风系统启动.The power supply controls for the air conditioning and ventilation systems are connected to the fire control center. When fire alarm occurs in a certain fire compartment, the ventilation system in this fire compartment stops operation and at the same time the smoke exhaust system and pressurized air supply system are started after judgement and confirmation by the fire control center.被其它房间包围的楼梯间将设置有加压通风系统.The staircases that are surounded by other rooms will be provided with overpressure ventilation systems.空调机组的详细技术参数集合在被报告末的技术数据报告.The exact technical datas of the AC- units are summarized in the " Technivcal Data Report at the end of the Report.。
本科毕业设计外文文献及译文文献、资料题目:Sealed building drainageand vent systems文献、资料来源:国道数据库文献、资料发表(出版)日期:2005.9.12院(部):市政与环境工程学院专业:给水排水工程班级:姓名:学号:指导教师:翻译日期: 2012.06外文文献:Sealed building drainage and vent systems—an application of active air pressure transient control and suppression AbstractThe introduction of sealed building drainage and vent systems is considered a viable proposition for complex buildings due to the use of active pressure transient control and suppression in the form of air admittance valves and positive air pressure attenuators coupled with the interconnection of the network's vertical stacks.This paper presents a simulation based on a four-stack network that illustrates flow mechanisms within the pipework following both appliance discharge generated, and sewer imposed, transients. This simulation identifies the role of the active air pressure control devices in maintaining system pressures at levels that do not deplete trap seals.Further simulation exercises would be necessary to provide proof of concept, and it would be advantageous to parallel these with laboratory, and possibly site, trials for validation purposes. Despite this caution the initial results are highly encouraging and are sufficient to confirm the potential to provide definite benefits in terms of enhanced system security as well as increased reliability and reduced installation and material costs.Keywords: Active control; Trap retention; Transient propagationNomenclatureC+-——characteristic equationsc——wave speed, m/sD——branch or stack diameter, mf——friction factor, UK definition via Darcy Δh=4fLu2/2Dgg——acceleration due to gravity, m/s2K——loss coefficientL——pipe length, mp——air pressure, N/m2t——time, su——mean air velocity, m/sx——distance, mγ——ratio specific heatsΔh——head loss, mΔp——pressure difference, N/m2Δt——time step, sΔx——internodal length, mρ——density, kg/m3Article OutlineNomenclature1. Introduction—air pressure transient control and suppression2. Mathematical basis for the simulation of transient propagation in multi-stack building drainage networks3. Role of diversity in system operation4. Simulation of the operation of a multi-stack sealed building drainage and vent system5. Simulation sign conventions6. Water discharge to the network7. Surcharge at base of stack 18. Sewer imposed transients9. Trap seal oscillation and retention10. Conclusion—viability of a sealed building drainage and vent system1.Air pressure transients generated within building drainage and vent systems as a natural consequence of system operation may be responsible for trap seal depletion and cross contamination of habitable space [1]. Traditional modes of trap seal protection, based on the Victorian engineer's obsession with odour exclusion [2], [3] and [4], depend predominantly on passive solutions where reliance is placed on cross connections and vertical stacks vented to atmosphere [5] and [6]. This approach, while both proven and traditional, has inherent weaknesses, including the remoteness of the vent terminations [7], leading to delays in the arrival of relieving reflections, and the multiplicity of open roof level stack terminations inherent within complex buildings. The complexity of the vent system required also has significant cost and space implications [8].The development of air admittance valves (AAVs) over the past two decades provides the designer with a means of alleviating negative transients generated as random appliance discharges contribute to the time dependent water-flow conditions within the system. AAVs represent an active control solution as they respond directly to the local pressure conditions, opening as pressurefalls to allow a relief air inflow and hence limit the pressure excursions experienced by the appliance trap seal [9].However, AAVs do not address the problems of positive air pressure transient propagation within building drainage and vent systems as a result of intermittent closure of the free airpath through the network or the arrival of positive transients generated remotely within the sewer system, possibly by some surcharge event downstream—including heavy rainfall in combined sewer applications.The development of variable volume containment attenuators [10] that are designed to absorb airflow driven by positive air pressure transients completes the necessary device provision to allow active air pressure transient control and suppression to be introduced into the design of building drainage and vent systems, for both ‘standard’ buildings and those requiring particular attention to be paid to the security implications of multiple roof level open stack terminations. The positive air pressure attenuator (PAPA) consists of a variable volume bag that expands under the influence of a positive transient and therefore allows system airflows to attenuate gradually, therefore reducing the level of positive transients generated. Together with the use of AAVs the introduction of the PAPA device allows consideration of a fully sealed building drainage and vent system.Fig. 1 illustrates both AA V and PAPA devices, note that the waterless sheath trap acts as an AA V under negative line pressure.Fig. 1. Active air pressure transient suppression devices to control both positive and negative surges.Active air pressure transient suppression and control therefore allows for localized intervention to protect trap seals from both positive and negative pressure excursions. This hasdistinct advantages over the traditional passive approach. The time delay inherent in awaiting the return of a relieving reflection from a vent open to atmosphere is removed and the effect of the transient on all the other system traps passed during its propagation is avoided.2.Mathematical basis for the simulation of transient propagation in multi-stack building drainage networks.The propagation of air pressure transients within building drainage and vent systems belongs to a well understood family of unsteady flow conditions defined by the St Venant equations of continuity and momentum, and solvable via a finite difference scheme utilizing the method of characteristics technique. Air pressure transient generation and propagation within the system as a result of air entrainment by the falling annular water in the system vertical stacks and the reflection and transmission of these transients at the system boundaries, including open terminations, connections to the sewer, appliance trap seals and both AAV and PAPA active control devices, may be simulated with proven accuracy. The simulation [11] provides local air pressure, velocity and wave speed information throughout a network at time and distance intervals as short as 0.001 s and 300 mm. In addition, the simulation replicates local appliance trap seal oscillations and the operation of active control devices, thereby yielding data on network airflows and identifying system failures and consequences. While the simulation has been extensively validated [10], its use to independently confirm the mechanism of SARS virus spread within the Amoy Gardens outbreak in 2003 has provided further confidence in its predictions [12].Air pressure transient propagation depends upon the rate of change of the system conditions. Increasing annular downflow generates an enhanced entrained airflow and lowers the system pressure. Retarding the entrained airflow generates positive transients. External events may also propagate both positive and negative transients into the network.The annular water flow in the ‘wet’ stack entrains an airflow due to the condition of ‘no slip’ established between the annular water and air core surfaces and generates the expected pressure variation down a vertical stack. Pressure falls from atmospheric above the stack entry due to friction and the effects of drawing air through the water curtains formed at discharging branch junctions. In the lower wet stack the pressure recovers to above atmospheric due to the traction forces exerted on the airflow prior to falling across the water curtain at the stack base.The application of the method of characteristics to the modelling of unsteady flows was first recognized in the 1960s [13]. The relationships defined by Jack [14] allows the simulation to model the traction force exerted on the entrained air. Extensive experimental data allowed the definition of a ‘pseudo-friction factor’ applicable in the wet stack and operable across the water annular flow/entrained air core interface to allow combined discharge flows and their effect on airentrainment to be modelled.The propagation of air pressure transients in building drainage and vent systems is defined by the St Venant equations of continuity and momentum [9],(1)(2)These quasi-linear hyperbolic partial differential equations are amenable to finite difference solution once transformed via the Method of Characteristics into finite difference relationships, Eqs. (3)–(6), that link conditions at a node one time step in the future to current conditions at adjacent upstream and downstream nodes, Fig. 2.Fig.2. St Venant equations of continuity and momentum allow airflow velocity and wave speed to bepredicted on an x-t grid as shown. Note , .For the C+ characteristic:(3)when(4)and the C- characteristic:(5)when(6)where the wave speed c is given byc=(γp/ρ)0.5. (7) These equations involve the air mean flow velocity, u, and the local wave speed, c, due to the interdependence of air pressure and density. Local pressure is calculated as(8)Suitable equations link local pressure to airflow or to the interface oscillation of trap seals.The case of the appliance trap seal is of particular importance. The trap seal water column oscillates under the action of the applied pressure differential between the transients in the network and the room air pressure. The equation of motion for the U-bend trap seal water column may be written at any time as(9)It should be recognized that while the water column may rise on the appliance side, conversely on the system side it can never exceed a datum level drawn at the branch connection.In practical terms trap seals are set at 75 or 50 mm in the UK and other international standards dependent upon appliance type. Trap seal retention is therefore defined as a depth less than the initial value. Many standards, recognizing the transient nature of trap seal depletion and the opportunity that exists for re-charge on appliance discharge allow 25% depletion.The boundary equation may also be determined by local conditions: the AAV opening and subsequent loss coefficient depends on the local line pressure prediction.Empirical data identifies the AAV opening pressure, its loss coefficient during opening and at the fully open condition. Appliance trap seal oscillation is treated as a boundary condition dependent on local pressure. Deflection of the trap seal to allow an airpath to,or from, the appliance or displacement leading to oscillation alone may both be modelled. Reductions in trap seal water mass during the transient interaction must also be included.3. Role of diversity in system operationIn complex building drainage networks the operation of the system appliances to discharge water to the network, and hence provide the conditions necessary for air entrainment and pressure transient propagation, is entirely random. No two systems will be identical in terms of their usage at any time. This diversity of operation implies that inter-stack venting paths will be established if the individual stacks within a complex building network are themselves interconnected. It is proposed that this diversity is utilized to provide venting and to allow serious consideration to be given to sealed drainage systems.In order to fully implement a sealed building drainage and vent system it would be necessary for the negative transients to be alleviated by drawing air into the network from a secure space andnot from the external atmosphere. This may be achieved by the use of air admittance valves or at a predetermined location within the building, for example an accessible loft space.Similarly, it would be necessary to attenuate positive air pressure transients by means of PAPA devices. Initially it might be considered that this would be problematic as positive pressure could build within the PAPA installations and therefore negate their ability to absorb transient airflows. This may again be avoided by linking the vertical stacks in a complex building and utilizing the diversity of use inherent in building drainage systems as this will ensure that PAPA pressures are themselves alleviated by allowing trapped air to vent through the interconnected stacks to the sewer network.Diversity also protects the proposed sealed system from sewer driven overpressure and positive transients. A complex building will be interconnected to the main sewer network via a number of connecting smaller bore drains. Adverse pressure conditions will be distributed and the network interconnection will continue to provide venting routes.These concepts will be demonstrated by a multi-stack network.4. Simulation of the operation of a multi-stack sealed building drainage and vent systemFig. 3 illustrates a four-stack network. The four stacks are linked at high level by a manifold leading to a PAPA and AAV installation. Water downflows in any stack generate negative transients that deflate the PAPA and open the AAV to provide an airflow into the network and out to the sewer system. Positive pressure generated by either stack surcharge or sewer transients are attenuated by the PAPA and by the diversity of use that allows one stack-to-sewer route to act as a relief route for the other stacks.The network illustrated has an overall height of 12m. Pressure transients generated within thenetwork will propagate at the acoustic velocity in air . This implies pipe periods, from stack base to PAPA of approximately 0.08s and from stack base to stack base of approximately 0.15s.In order to simplify the output from the simulation no local trap seal protection is included—for example the traps could be fitted with either or both an AAV and PAPA as examples of active control. Traditional networks would of course include passive venting where separate vent stacks would be provided to atmosphere, however a sealed building would dispense with this venting arrangement.Fig.3.Four stack building drainage and vent system to demonstrate the viability of a sealed building system.Ideally the four sewer connections shown should be to separate collection drains so that diversity in the sewer network also acts to aid system self venting. In a complex building this requirement would not be arduous and would in all probability be the norm. It is envisagedthat the stack connections to the sewer network would be distributed and would be to a below ground drainage network that increased in diameter downstream. Other connections to the network would in all probability be from buildings that included the more traditional open vent system design so that a further level of diversity is added to offset any downstream sewer surcharge events of long duration. Similar considerations led to the current design guidance for dwellings.It is stressed that the network illustrated is representative of complex building drainage networks. The simulation will allow a range of appliance discharge and sewer imposed transient conditions to be investigated.The following appliance discharges and imposed sewer transients are considered:1. w.c. discharge to stacks 1–3 over a period 1–6s and a separate w.c. discharge to stack 4 between 2 and 7s.2. A minimum water flow in each stack continues throughout the simulation, set at 0.1L/s, to represent trailing water following earlier multiple appliance discharges.3. A 1s duration stack base surcharge event is assumed to occur in stack 1 at 2.5s.4. Sequential sewer transients imposed at the base of each stack in turn for 1.5s from 12 to 18s.The simulation will demonstrate the efficacy of both the concept of active surge control and inter-stack venting in enabling the system to be sealed, i.e. to have no high level roof penetrations and no vent stacks open to atmosphere outside the building envelope.The imposed water flows within the network are based on ‘real’ system values, being representative of current w.c. discharge characteristics in terms of peak flow, 2l/s, overall volume, 6l, and duration, 6s. The sewer transients at 30mm water gauge are representative but not excessive. Table 1 defines the w.c. discharge and sewer pressure profiles assumed.Table1. w.c. discharge and imposed sewer pressure characteristicsw.c. discharge characteristic Imposed sewer transient at stack baseTime Discharge flow Time PressureSeconds l/s Seconds Water gauge (mm)Start time 0.0 Start time 0.0+2 2.0 +0.5 30.0+4 2.0 +0.5 30.0+6 0.0 +0.5 0.05. Simulation conventionsIt should be noted that heights for the system stacks are measured positive upwards from the stack base in each case. This implies that entrained airflow towards the stack base is negative. Airflow entering the network from any AAVs installed will therefore be indicated as negative. Airflow exiting the network to the sewer connection will be negative.Airflow entering the network from the sewer connection or induced to flow up any stack will be positive.Water downflow in a vertical is however regarded as positive.Observing these conventions will allow the following simulation to be better understood.6. Water discharge to the networkTable 1 illustrates the w.c. discharges described above, simultaneous from 1s to stacks 1–3 and from 2s to stack 4. A base of stack surcharge is assumed in stack 1 from 2.5 to 3s. As a result it will be seen from Fig. 4 that entrained air downflows are established in pipes 1, 6 and 14 asexpected. However, the entrained airflow in pipe 19 is into the network from the sewer. Initially, as there is only a trickle water flow in pipe 19, the entrained airflow in pipe 19 due to the w.c. discharges already being carried by pipes 1, 6 and 14, is reversed, i.e. up the stack, and contributes to the entrained airflow demand in pipes 1, 6 and 14. The AAV on pipe 12 also contributes but initially this is a small proportion of the required airflow and the AAV flutters in response to local pressure conditions.Fig.4.Entrained airflows during appliance discharge.Following the w.c. discharge to stack 4 that establishes a water downflow in pipe 19 from 2 s onwards, the reversed airflow initially established diminishes due to the traction applied by the falling water film in that pipe. However, the suction pressures developed in the other three stacks still results in a continuing but reduced reversed airflow in pipe 19. As the water downflow in pipe 19 reaches its maximum value from 3 s onwards, the AAV on pipe 12 opens fully and an increased airflow from this source may be identified. The flutter stage is replaced by a fully open period from 3.5 to 5.5 s.Fig. 5 illustrates the air pressure profile from the stack base in both stacks 1 and 4 at 2.5 s into the simulation. The air pressure in stack 4 demonstrates a pressure gradient compatible with the reversed airflow mentioned above. The air pressure profile in stack 1 is typical for a stack carrying an annular water downflow and demonstrates the establishment of a positive backpressure due to the water curtain at the base of the stack.Fig.5.Air pressure profile in stacks 1 and 4 illustrating the pressure gradient driving the reversed airflow in pipe 19.The initial collapsed volume of the PAPA installed on pipe 13 was 0.4l, with a fully expanded volume of 40l, however due to its small initial volume it may be regarded as collapsed during this phase of the simulation.7. Surcharge at base of stack 1Fig. 6 indicates a surcharge at the base of stack 1, pipe 1 from 2.5 to 3 s. The entrained airflow in pipe 1 reduces to zero at the stack base and a pressure transient is generated within that stack, Fig.6. The impact of this transient will also be seen later in a discussion of the trap seal responses for the network.Fig.6.Air pressure levels within the network during the w.c. discharge phase of the simulation. Note surcharge at base stack 1, pipe 1 at 2.5s.It will also be seen, Fig. 6, that the predicted pressure at the base of pipes 1, 6 and 14, in the absence of surcharge, conform to that normally expected, namely a small positive back pressure as the entrained air is forced through the water curtain at the base of the stack and into the sewer. In the case of stack 4, pipe 19, the reversed airflow drawn into the stack demonstrates a pressure drop as it traverses the water curtain present at that stack base.The simulation allows the air pressure profiles up stack 1 to be modelled during,and following, the surcharge illustrated in Fig. 6. Fig. 7(a) and (b) illustrate the air pressure profiles in the stack from 2.0 to 3.0 s, the increasing and decreasing phases of the transient propagation being presented sequentially. The traces illustrate the propagation of the positive transient up the stack as well as the pressure oscillations derived from the reflection of the transient at the stack termination at the AAV/PAPA junction at the upper end of pipe 11.Fig.7.(a) Sequential air pressure profiles in stack 1 during initial phase of stack base surcharge. (b) Sequential air pressure profiles in stack 1 during final phase of stack base surcharge.8. Sewer imposed transientsTable 2 illustrates the imposition of a series of sequential sewer transients at the base of eachstack. Fig. 8 demonstrates a pattern that indicates the operation of both the PAPA installed on pipe 13 and the self-venting provided by stack interconnection.Fig.8.Entraind airflows as a result of sewer imposed pressure transients.As the positive pressure is imposed at the base of pipe 1 at 12 s, airflow is driven up stack 1 towards the PAPA connection. However, as the base of the other stacks have not a yet had positive sewer pressure levels imposed, a secondary airflow path is established downwards to the sewer connection in each of stacks 2–4, as shown by the negative airflows in Fig. 8.As the imposed transient abates so the reversed flow reduces and the PAPA discharges air to the network, again demonstrated by the simulation, Fig. 8. This pattern repeats as each of the stacks is subjected to a sewer transient.Fig. 9 illustrates typical air pressure profiles in stacks 1 and 2. The pressure gradient in stack 2 confirms the airflow direction up the stack towards the AAV/PAPA junction. It will be seen that pressure continues to decrease down stack 1 until it recovers, pipes 1 and 3, due to the effect of the continuing waterflow in those pipes.The PAPA installation reacts to the sewer transients by absorbing airflow, Fig. 10. The PAPA will expand until the accumulated air inflow reaches its assumed 40 l volume. At that point the PAPA will pressurize and will assist the airflow out of the network via the stacks unaffected by the imposed positive sewer transient. Note that as the sewer transient is applied sequentially from stacks 1–4 this pattern is repeated. The volume of the high level PAPA, together with any others introduced into a more complex network, could be adapted to ensure that no system pressurization occurred.Fig.9.Air pressure profile in stack 1 and 2 during the sewer imposed transient in stack 2, 15s into the simulation.Fig.10.PAPA volume and AAV throughflow during simulation.The effect of sequential transients at each of the stacks is identifiable as the PAPA volume decreases between transients due to the entrained airflow maintained by the residual water flows in each stack.9. Trap seal oscillation and retentionThe appliance traps connected to the network monitor and respond to the local branch air pressures. The model provides a simulation of trap seal deflection, as well as final retention. Fig. 11(a,b) present the trap seal oscillations for one trap on each of the stacks 1 and 2, respectively. As the air pressure falls in the network, the water column in the trap is displaced so that the appliance side water level falls. However, the system side level is governed by the level of the branch entry connection so that water is lost to the network. This effect is illustrated in both Fig. 11(a) and (b).Transient conditions in the network result in trap seal oscillation, however at the end of the event the trap seal will have lost water that can only be replenished by the next appliance usage. If the transient effects are severe than the trap may become totally depleted allowing a potential cross contamination route from the network to habitable space. Fig. 11(a) and (b) illustrate the trap seal retention at the end of the imposed network transients.Fig.11.(a) Trap seal oscillation, trap 2. (b) Trap seal oscillation, trap 7.Fig. 11(a), representing the trap on pipe 2, illustrates the expected induced siphonage of trap seal water into the network as the stack pressure falls. The surcharge event in stack 1 interrupts this process at 2s. The trap oscillations abate following the cessation of water downflow in stack 1. The imposition of a sewer transient is apparent at 12s by the water surface level rising in the appliance side of the trap. A more severe transient could have resulted in ‘bubbling through’ at this stage if the trap system side water surface level fell to the lowest point of the U-bend.The trap seal oscillations for traps on pipes 7, Fig. 11(b) and 15, are identical to each other until the sequential imposition of sewer transients at 14 and 16s. Note that thesurcharge in pipe 1 does not affect these traps as they are remote from the base of stack 1. The trap on pipe 20 displays an initial reduction in pressure due to the delay in applied water downflow. The sewer transient in pipe 19 affects this trap at around 18s.As a result of the pressure transients arriving at each trap during the simulation there will be a loss of trap seal water. This overall effect results in each trap displaying an individual water seal retention that depends entirely on the usage of the network. Trap 2 retains 32mm water seal while traps 7 and 15 retain 33mm. Trap 20 is reduced to 26mm water seal. Note that the traps on pipes 7 and 15 were exposed to the same levels of transient pressure despite the time difference in arrival of the sewer transients. Fig. 11(a) and (b) illustrate the oscillations of the trap seal column as a result of the solution of the trap seal boundary condition, Eq. (10), with the appropriate C+ characteristic. This boundary condition solution continually monitors the water loss from the trap and at the end of the event yields a trap seal retention value. In the example illustrated the initial trap seal values were taken as 50mm of water, common for appliances such as w.c.'s and sinks.10. Conclusion—viability of a sealed building drainage and vent systemThe simulation presented confirms that a sealed building drainage system utilizing active transient control would be a viable design option. A sealed building drainage system would offer the following advantages:• System security would be immeasurably enhanced as all high-level open system terminations would be redundant.• System complexity would be reduced while system predictability would increase.• Space and material savings would be achieved within the construction phase of any installation.These benefits would be realized provided that active transient control and suppression was incorporated into the design in the form of both AAV to suppress negative transients and variable volume containment devices (PAPA) to control positive transients.The diversity inherent in the operation of both building drainage and vent systems and the sewers connected to the building have a role in providing interconnected relief paths as part of the system solution.The method of characteristics based finite difference simulation presented has provided output consistent with expectations for the operation of the sealed system studied. The accuracy of the simulation in other recent applications, including the accurate corroboration of the SARS spread mechanism within the Amoy Gardens complex in Hong Kong in 2003, provides a confidence level in the results presented.。