Previous Issue: 28 April 2009 Next Planned Update: 22 May 2016Revised paragraphs are indicated in the right marginPage 1 of 15Primary contact: Maatoug, Maatoug A on 966-3- 8747960Engineering ProcedureSAEP-2222 May 2011Tank Calibration RequirementsDocument Responsibility: Custody Measurement Standards CommitteeSaudi Aramco DeskTop StandardsTable of Contents1 Scope............................................................2 2 Conflicts and Deviations................................ 23 Applicable Documents................................... 24 Definitions and Acronyms.............................. 35 Instructions.................................................... 56 Responsibilities.............................................. 87 Activity Matrix.............................................. 10 Attachment I – Required Information on the Tank Capacity Table................. 12 Attachment II – Qualifications of theThird Party Inspection Agency (15)Next Planned Update: 22 May 2016 Tank Calibration Requirements 1 ScopeThis procedure establishes the instructions and responsibilities for the calibration ofall Saudi Aramco royalty/custody tank gauging applications. This procedure is alsoapplicable to the inventory tanks that have the potential to be used for custody orroyalty measurement applications in case of the metering system failures. Organizations for which responsibilities are specified include, but are not limited to:∙The Proponent Organization∙Saudi Aramco Project Management Team (SAPMT)∙Process & Control Systems Department (P&CSD)2 Conflicts and Deviations2.1 Any conflicts between this procedure and other applicable Saudi AramcoEngineering Standards (SAESs), Materials System Specifications (SAMSSs),Standard Drawings (SASDs), or industry standards, codes, and forms shall beresolved in writing by the Manager, Process & Control Systems Department ofSaudi Aramco, Dhahran.2.2 Direct all requests to deviate from this procedure in writing in accordance withSAEP-302 to the Manager, Process & Control Systems Department of SaudiAramco, Dhahran.2.3 Direct all requests for interpretation of this procedure in writing to the Chairman,Custody Measurement Standards Committee for resolution. The Chairman,Custody Measurement Standards Committee shall be solely responsible fordetermining whether a proposed request meets the requirements of this procedure.3 Applicable DocumentsThe procedures covered by this document shall comply with the latest edition of thereferences listed below, unless otherwise noted:3.1 Saudi Aramco ReferenceSaudi Aramco Engineering ProcedureSAEP-302Instructions for Obtaining a Waiver of aMandatory Saudi Aramco EngineeringRequirementNext Planned Update: 22 May 2016 Tank Calibration Requirements3.2 Industry Codes and StandardsAmerican Petroleum Institute (API) Manual of Petroleum MeasurementStandards (MPMS)Chapter 2.2A Measurement and Calibration of UprightCylindrical Tanks by the Manual StrappingMethodChapter 2.2B Calibration of Upright Cylindrical Tanks usingthe Optical-Reference Line MethodChapter 2.2C Calibration of Upright Cylindrical Tanks usingthe Optical-Triangulation MethodChapter 2.2D Calibration of Upright Cylindrical Tanks usingthe Internal Electro-optical Distance RangingMethodChapter 2.2E Calibration of Horizontal Cylindrical Tanks-Part 1: Manual MethodsChapter 2.2F Calibration of Horizontal Cylindrical Tanks-Part 2: Internal Electro-Optical Distance-Ranging MethodStandard 2552 Method for Measurement and Calibration ofSpheres and SpheroidsStandard 2555 Liquid Calibration of Tanks4 Definitions and Acronyms4.1 DefinitionsApprove: Review and formal acceptance characterized by the signature of thefinal authorizing individual or organization.Capacity Table: A table often referred to as a tank capacity table or calibrationtable, showing the capacities of or volumes in a tank for various liquid levelsmeasured from the reference gauge point.Critical Zone: The region between initial and complete flotation of a floatingroof.Custody Transfer Measurement: A specialized form of measurement thatprovides quantity and quality information used for the physical and fiscaldocumentation of a change in ownership and/or responsibility of hydrocarboncommodities. This includes measurement of hydrocarbon liquid movementsNext Planned Update: 22 May 2016 Tank Calibration Requirements(deliveries or receipts) between Saudi Aramco and its customers, suppliers, jointventures and transport contractors including VELA ships.Customer: The party that takes ownership or responsibility of a hydrocarboncommodity from Saudi Aramco.Datum plate: A level metal plate located directly under the reference gaugepoint to provide a fixed contact surface from which liquid depth measurementcan be made.Deadwood: Deadwood refers to any object within the tank, including a floatingroof, which displaces liquid and reduces the capacity of the tank; also anypermanent appurtenances on the outside of the tank, such as cleanout boxes ormanholes, which increase the capacity of the tank. Deadwood is positive if itincreases tank capacity or negative if it decreases capacity.External Floating Roof: A cover over an open top storage tank consisting of adeck which rests upon the liquid being contained.Internal Floating Roof: A cover within a fixed roof tank which rests upon thepetroleum liquid being contained.Master Tape: A tape that is used for calibrating working tapes for tankmeasurements and is identified with a report of calibration at 68°F (20°C) and aspecific tension designated by the National Institute of Standards andTechnology (NIST) or an equivalent international standard organization.Recomputation: The process of re-generating the capacity tables through softcalculations, without repeating the field calibration measurements. It involves,simply, updating or revising the capacity table using previously established tankdiametersReference Gauge Height: The distance from the datum plate or tank bottom tothe reference gauge point.Royalty Measurement: A specialized form of measurement that is used as thebasis for paying royalty to the Saudi Arabian Government.SAP: The Saudi Aramco main system for enterprise resource management.Spheres: A stationary liquid storage tank, supported on columns so that theentire tank shall be aboveground.Spheroid: A stationary liquid storage tank having a shell of double curvature.Any horizontal cross-section is a series of circular arcs.Next Planned Update: 22 May 2016 Tank Calibration Requirements Strapping: The measurement of the external circumference of a vertical orhorizontal cylindrical tank by stretching a steel tape around each course of thetank's plates and recording the measurement.Tank Calibration: The process of determining the capacity of a tank throughfield measurements.Third Party Inspection Agency: An independent inspection agency whosefunction is to conduct an unbiased inspection of certain systems, equipment,materials, etc., against a set of standards, guidelines or procedures. For purposesof this SAEP, the Third Party Inspector has particular knowledge of andexperience of conducting tank calibration in accordance with industry custodymeasurement standards and procedures.4.2 AbbreviationsAPI American Petroleum InstituteCMU Custody Measurement Unit of Process & Control SystemsDepartmentEODR Electro Optical Distance RangingORLM Optical Reference Line MethodMPMS Manual of Petroleum Measurement StandardsP&CSD Process & Control Systems DepartmentSA Saudi AramcoSAEP Saudi Aramco Engineering ProcedureSAES Saudi Aramco Engineering StandardSAMSS Saudi Aramco Material SpecificationSAP Systems Application ProgrammingSASD Saudi Aramco Engineering Standard Drawing5 Instructions5.1 GeneralThis procedure shall be used in conjunction with existing international standardsand is not intended to replace the standards referred to in Section 3 above.The reference temperature for all tank capacity tables shall be 60°F forRefineries, Terminals, Gas Plants and 15°C for Distribution Operations.Next Planned Update: 22 May 2016 Tank Calibration Requirements5.2 Calibration/Re-calibration FrequenciesAll new tanks/vessels used for custody transfer measurement must undergocalibration prior to being put in service.All tanks/vessels must be recalibrated in conjunction with Testing andInspection (T&I), or when a major repair is don for tank bottom.The upright cylindrical tank shall be recalibrated in accordance within volume detected to invoke this appendix requirement.5.3 Precalibration PreparationsPrior to calibration, the upright cylindrical tanks, horizontal tanks, spheres andspheroids must have been filled to 95% of their design operating capacity for aminimum period of 24 hours with a liquid at least as dense as the product theywill normally store.Commentary Note:This requirement is considered met if the tank/vessel has been already hydro-tested.5.4 Recomputation RequirementsThe capacity table of horizontal tanks, spheres and spheroids must berecomputed if variation in product operating temperatures and temperatureassumed during calibration is greater than 11°C (20°F).Commentary Note:Variations in the product's calibration specific gravity and operating specificgravity greater than 20% will require a recomputation of the table, due to thehydrostatic head effect expansion on tanks/vessels.Floating roof correction table requires recomputation when any variation in theroof's weight, due to repairs or modifications, results in a change in the roofdeadweight that altered the tank predetermined volume by 0.02% or more.Commentary Note:While recalibration involves reestablishing tank diameters through standardcalibration methods and developing new tank capacity tables for custody andnon-custody transfers, recomputation, involves simply updating or revising thecapacity table using previously established tank diameters.Next Planned Update: 22 May 2016 Tank Calibration Requirements5.5 Acceptable Calibration TechnologiesFollowing is a list of the calibration technologies acceptable for tank/vesselcalibrations along with the reference standard the methods' implementationshould comply to. The methods are arranged in the order of priority, based onthe most efficient means of calibration for a given set of conditions.(1) Internal Electro Optical Distance Ranging Method (EODR),API Chapter 2.2D(2) Internal Electro Optical Distance Ranging Method (EODR),API Chapter 2.2F(3) Optical Reference Line Method (ORLM), API Chapter 2.2B(4) Manual Strapping Method(Strapping), API Chapter 2.2A(5) Optical Triangulation Method, API Chapter 2.2C(6) Manual Methods, API Chapter 2.2E(7) Liquid Calibration, API 2555(8) Method for Measurement and Calibration of Spheres and Spheroids,API STD 2552Commentary Note:All these methods essentially provide alternate techniques for measuring tankdiameters. While manual strapping is limited to external calibrations, theremaining methods can be used either externally or internally.5.6 Technology Selection Guidelinesa. The application of the EODR shall be limited to tanks/vessels that aregreater than 5 meters in diameter.b. The application of liquid calibration shall be limited to tanks/vessels thatare smaller than 5 meters in diameter.c. If a tank/vessel is insulated, it should be calibrated internally.d. External and internal EODR shall be used for all tanks/vessels that aregreater than 5 meters in diameter with no insulation.e. Either Internal or external ORLM shall be used for floating roof tanks.f. External ORLM can be used for fixed roof tanks with no insulation andhaving not more than a single wind girder.g. If the tank has multiple external wind girders, it should be calibrated eitherby external/internal EODR or internal ORLM.Next Planned Update: 22 May 2016 Tank Calibration Requirementsh.bottom elevations shall be sighted along radii every 45 degrees. Alongthese radii, elevations should be obtained at equally spaced intervals notmore than 10 feet (3 meters) from the tank's center to its shell. Liquidcalibration method is permitted to be used whenever the tank containsirregular shaped deadwood (e.g., steam coils, etc.).i. Spheres and spheroids shall be calibrated in accordance with API STD2552, Method for Measurement and Calibration of Spheres and Spheroids.6 ResponsibilitiesThe Saudi Aramco organizations with tank/vessels calibration responsibilities shallensure that their personnel become familiar with this SAEP.6.1 Saudi Aramco Project Management Team (SAPMT)a. Initiate calibration request for new tanks/vessels,b. Inform CMU of the calibration of new tanks only if is used for royaltytransfer,c. Request list of Approved Third Party Inspection Agencies,d. Contract tank calibrations to an approved Third Party Inspection Agency,e. Inform the Proponent to witness the calibration process,f. Obtain the capacity tables from the Third Party Inspection Agency,g. Request CMU's review for capacity tables of new royalty tanks,h. Provide two hardcopy and two electronic tables in US Customary unitsand/or (based on application requirement) SI units of the final approvedcalibration calculation and the capacity table to the Proponent.i. Close the activity.6.2 The Proponent Organizationa. Initiate requests for in-service tanks/vessels per the frequencyrequirements set forth in Section 5.2 above,b. Inform CMU of the calibration of new tanks if it is used for royaltytransfer applications,c. Request list of the approved Third Party Inspection Agencies,d. Contract tank calibrations to an approved Third Party Inspection Agency,e. Provide the operating data (operating temperature, density at operatingtemperature, operating pressure) to the Third Party Inspection Agency,Next Planned Update: 22 May 2016 Tank Calibration Requirementsf. Ensure the equipment used has been calibrated and has valid certificatesthat are traceable to National Institute of Standard and Technology (NIST)or other approved standards organization,g. Witness the field calibration process and ensure that the Third PartyInspection Agency is performing the tank/vessel calibration calculations inaccordance API MPMS Chapter 2.2A and API STD 2552, including, butnot limited to, the following capacity table correction factors,i. master tape corrections.ii. working tape correction.iii. tape rise correction.iv. tank shell temperature expansion correction.v. hydrostatic head effect correction.vi. tilt correction.vii. floating roof gravity adjustment.h. Consult with CMU if a technical inquiry about the calibration and/ordocumentation process cannot be resolved internally,i. Review the draft calibration calculations,j. Review the produced capacity tables and make sure they comply with the requirements in Attachment I,k. Submit the capacity tables for the calibration of the new tanks to theSAPMT,l. Submit initial capacity tables of new royalty tanks only to CMU forreview.m. Maintain two hardcopy and two electronic tables in US Customary units and/or (based on application requirement) SI units of the final approvedcalibration calculation and the capacity table to the proponent,n. Update the SAP Tank Gauging System with the new approved capacitytable, if applicable,o. Inform the SAPMT of the completion of the tank calibration,p. Commission the tank,q. Close the activity.6.3 Process & Control Systems Department (P&CSD)The Process & Control Systems Department/Custody Measurement Unit (CMU)is responsible for providing technical assistance to the Proponent(s) on mattersNext Planned Update: 22 May 2016 Tank Calibration Requirements pertaining to tank calibrations. Specific responsibilities of CMU aresummarized below:a. Review the qualifications of the Third Party Inspection Agencies and makesure they meet all of the requirements detailed in Attachment II.b. Maintain the list of Approved Third Party Inspection Agencies.c. Submit the list of the Approved Third Party Inspection Agencies to theSAPMT and the Proponent upon request.d. Upon request from the proponent, provide consultation if a technicalinquiry about the calibration and/or documentation process cannot beresolved internally.e. Review initial capacity tables of new royalty tanks only.7 Activity MatrixThe following matrix summarizes the general sequence of activities and corresponding responsible organizations for calibrating tanks. Detailed requirements for eachorganization are specified in Section 6.Next Planned Update: 22 May 2016 Tank Calibration RequirementsNote:(1) SAPMT initiates calibration request for new tanks/vessels. The Proponent initiates calibrationrequest for tanks/vessels in-service per the frequency requirements set forth in Section 5 above.For BI-1900, the proponent will assume the responsibilities of SAPMT.Revision Summary22 May 2011 Revised the "Next Planned Update". Reaffirmed the contents of the document, and reissuedwith minor changes.Next Planned Update: 22 May 2016 Tank Calibration Requirements Attachment I – Required Information on the Tank Capacity TableThe final capacity table should contain the following minimum documentation details:1. Tank Identificationa. The site or installation tank numberb. Location Titled with “Saudi Arabian Oil Company”c. The type of tank in serviced. The name of the plant, owner or operatore. The name and address of the calibration authority or company which carriedout the calibration.2. Product InformationThe product name and density of the liquid stored in the tank when in service andused in the computation of the tank capacity tables.3. Operational Detailsa. The standard temperature (60°F for U.S. Customary, or 15°C for metrictables) for which the tank capacity table has been calculated.b. Operating temperature and pressurec. Table type (innage or ullage)4. Traceability and Tracking Detailsa. The date a new tank was first calibratedb. The date an old tank was recalibratedc. Calibration agent reference document numberd. The date the tank was recomputed, and the method used for recomputatione. The date of the calibration along with specific references to the methodadopted in calibrating the tank bottomf. Page numberg. Reference to the standard on which the calibration is basedh. The Third Party Inspection Agency shall sign and stamp each page of thecertificate.Next Planned Update: 22 May 2016 Tank Calibration Requirements5. Tank Dimensionsa. The nominal height and diameter of the tankb. Description of the tank bottom type, along with the method used todetermine the bottom volumec. Integrated deadwood, accurately accounted for as to location and volume,and included as an attachmentd. Note on capacity table that the volume below the striking plate is included inthe first measuremente. The shell height, is measured as the vertical distance between the bottom ofthe bottom angle and top of the top angle and measured near the referencegauge hatchf. Reference height measurement point locations shall be clearly identified ontank capacity tablesg. The height of the datum-points(s) with reference to the junction of the tankshell and bottom platingh. If an automatic gauging system is installed, the height of the gauge datumpoint with reference to the junction of the tank shell and bottom platingi. Maximum fill heightj. Safe fill height specified by the tank ownerk. The amount of tilt in shell height is measured and recorded.l. Height of the striking point (datum plate) from the tank bottom platem. The decimal (fraction) average volume for each strapping page.6. Floating Roof Informationa. The allowance for the roof is to be treated as deadwood and incorporated inthe tank capacity table directly, not as a separate attachmentb. The density of the liquid for which the roof has been calculated shall berecorded on the table directlyc. The apparent mass in air of the roof and accessoriesd. The displacement volume of the roof and the floating roof correction factormethod statemente. A defined level (Level A), with the distance above the dip point designatingwhere the roof is at restf. A defined level (Level B), with the distance when the roof is just fullyfloating in the lowest-density liquid to be contained in the tankNext Planned Update: 22 May 2016 Tank Calibration Requirementsg. The part of the capacity table between Level A and Level B is marked as“Not Accurate”h. Critical zones shall be identified within the tablei. The range where floating roof adjustment not to be performed.7. Tank Shell Correctiona. A shell temperature expansion factor table is to be developed in incrementsof 5°F or 3°C and included as an attachment to the capacity table for aspecific operating range.b. Include the equation for determining the shell temperature.Next Planned Update: 22 May 2016 Tank Calibration Requirements Attachment II – Qualifications of the Third Party Inspection AgencyThe Third Party Inspection Agency shall meet all of the following requirements:1. The agency has provided similar services for a minimum of 3 years. It shallsubmit a list of companies for which it has provided similar calibration servicesover the preceding 3 years.2. The agency's personnel performing the field measurements and calculations musthave a minimum of one year experience with the application of the APItank/vessel calibration standards. Experience shall be documented by submittal ofresume and verifiable work histories.3. The agency shall have written procedures which meet the requirements of APItank/vessel calibration standards. It shall submit the written procedures forreview.4. The agency shall have equipment as specified in API MPMS Chapter 2.2. It shallsubmit a list of the equipment it intends to use along with corresponding validcalibration certificates.5. The agency shall demonstrate it is ISO-certified and that it is activelyadministering a quality assurance program. It shall submit a copy of its ISOcertification and his quality assurance program details for review.6. The agency shall demonstrate that it is capable of performing the tank/vesselcalibration calculations. It shall provide a minimum of two samples of previouscalibration results, including field data and all calculations.7. The agency shall provide financial and insurance documentations as deemednecessary by the Contracting Unit to ensure he has adequate liability coverage fordamages done to Saudi Aramco facilities.。
