1、Manual of PetroleumMeasurement StandardsChapter 2Tank CalibrationSection 8BRecommended Practice for the Establishment of the Location of the Reference Gauge Point and the Gauge Height of Tanks on Marine Tank VesselsFIRST EDITION, AUGUST 1995REAFFIRMED: OCTOBER 2009Manual of PetroleumMeasurement Stan
2、dardsChapter 2Tank CalibrationSection 8BRecommended Practice for the Establishment of the Location of the Reference Gauge Point and the Gauge Height of Tanks on Marine Tank VesselsMeasurement Coordination FIRST EDITION, AUGUST 1995REAFFIRMED: OCTOBER 2009SPECIAL NOTES1. API PUBLICATIONS NECESSARILY
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8、LICATIONS AND MATERIALS IS PUBLISHED ANNUALLY AND UPDATEDQUARTERLY BY API, 1220 L STREET, N.W., WASHINGTON, D.C. 20005.Copyright 1995 American Petroleum InstituteiiiFOREWORDThe API Manual of Petroleum Measurement Standards (MPMS) is currently available.The manual will eventually include all subject
9、matter now found in API measurementpublicationsincluding evaporation loss measurementas well as new material andrevised editions of existing MPMS material when revisions are completed.API publications may be used by anyone desiring to do so. Every effort has been madeby the Institute to assure the a
10、ccuracy and reliability of the data contained in them; however,the Institute makes no representation, warranty, or guarantee in connection with this publi-cation and hereby expressly disclaims any liability or responsibility for loss or damageresulting from its use or for the violation of any federa
11、l, state, or municipal regulation withwhich this publication may conflict.Suggested revisions are invited and should be submitted to Measurement Coordination,Exploration and Production Department, American Petroleum Institute, 1220 L Street,N.W., Washington, D.C. 20005. vCONTENTSPageSECTION 8BRECOMM
12、ENDED PRACTICE FOR THEESTABLISHMENT OF THE LOCATION OF THEREFERENCE GAUGE POINT AND THE GAUGEHEIGHT OF TANKS ON MARINE TANK VESSELS2.8B.0 Introduction 12.8B.1 Scope and Field of Application 12.8B.2 References 12.8B.3 Safety . 12.8B.4 Tank Measuring Equipment . 12.8B.5 Measurement Conditions and Tole
13、rances 12.8B.5.1 Measurement Conditions. 12.8B.5.2 Measurement Tolerances. 22.8B.6 Number and Location of Reference Gauge Points. 22.8B.6.1 Number of Reference Gauge Points 22.8B.6.2 Location of Reference Gauge Points (Tank Ships) . 22.8B.6.3 Location of Reference Gauge PointsCombination Carriers (O
14、BOs) 32.8B.6.4 Location of Reference Gauge Points (Barges) 32.8B.7 Gauging Hatches 42.8B.7.1 Primary Gauging Hatch. 42.8B.7.2 Other Manual Gauge Points 52.8B.8 Measurement Procedures . 52.8B.8.1 Preliminary 52.8B.8.2 Measurement of Gauge Point Locations . 62.8B.8.3 Measurement of Reference Gauge Hei
15、ght 72.8B.8.4 Expansion Trunk Cover Gasket Compression. 72.8B.9 Calculation Procedures 8Figures1Longitudinal Section Through Typical Cargo Tank Showing Recommended Gauge Point Locations for Tankers 32Transverse Section Through Typical Cargo Tank Showing Gauge Point Locations 43Transverse Section Thr
16、ough Typical Cargo Tank Showing Recommended Gauge Point Locations for Tankers 54Longitudinal Section Through Cargo Hold/Tank of a Combination Carrier (OBO) Showing Recommended Gauge Point Locations . 65Transverse Section Through Cargo Hold/Tank of a Combination Carrier(OBO) Showing Recommended Gauge
17、 Point Locations 76Longitudinal Section Through Cargo Tank of a Typical Inland Waterway Tank Barge Showing Recommended Gauge Point Locations 87Transverse Section Through Cargo Tank of a Typical Inland Waterway Tank Barge Showing Recommended Gauge Point Locations 98Illustration of Length Between Draf
18、t Marks 70,000 DWT Tanker 109Sketch for Locating Gauge Point 1010Check Measurement for Gasket Compression 112.8B.0 IntroductionThis document is intended to supplement the calibrationprocedures described in API Chapter 2.8A, “Calibration ofTanks on Ships and Ocean-Going Barges,” and API Chapter2.7, “
19、Calibration of Tanks on Barges” of the Manual ofPetroleum Measurement Standards (MPMS).2.8B.1 Scope and Field of ApplicationThis recommended practice is intended as a guide forestablishing reference gauge heights during calibration ofmarine tank vessels. In many cases this calibration is carriedout
20、by shipyard engineers who may not be fully familiarwith petroleum measurement requirements nor the use ofsuch measurements by petroleum inspectors and tanker oper-ating personnel. This procedure is also for recalibration ofvessels.The importance of establishing an accurate referencegauge height for
21、tanks on marine tank vessels cannot beoverstressed. Such tanks are generally calibrated in ullages(outages) whereas in measuring quantities remainingonboard (ROB) or free water, it is frequently more conve-nient and accurate to measure innages. The reference gaugeheight is a necessity in converting
22、ullage to innage. Also, indetermining the volume of the ROB, the reference gaugeheight is a factor in every wedge formula, for the establish-ment of wedge tables.API MPMS Chapters 2.7 and 2.8A provide three methodsof calibrating the volumes of tanks on marine tank vessels:calibration by linear measu
23、rement, liquid calibration, andcalibration from vessel drawings. The measurement andestablishment of the reference gauge height, however, canonly be determined by direct linear measurement.2.8B.2 ReferencesUnless otherwise specified, the most recent editions orrevisions of the following standards, c
24、odes, and specifica-tions shall, to the extent specified herein, form a part of thisstandard.APIManual of Petroleum Measurement StandardsChapter 2.7, “Calibration of Tanks on Barges”Chapter 2.8A, “Calibration of Tanks on Ships andOcean-Going Barges”DOT133 Code of Federal RegulationsIMO2Resolution of
25、 the International Conference on TankerSafety and Pollution PreventionNFPA3306 Control of Gas Hazards on Vessels2.8B.3 SafetyPrior to entering any compartment, permission must beobtained from the vessels master, senior deck officer, autho-rized shipyard official, or other responsible person in charg
26、e.This responsible person should be able to supply informationregarding particular materials and conditions or the appli-cable Material Safety Data Sheet. Before entering thecompartment, a valid marine chemists certificate must beobtained indicating that the compartment is “Safe forWorkers” and/or “
27、Safe for Hot Work,” as prescribed inNational Fire Protection Association 306, Control of GasHazards on Vessels. Regulations of the U.S. Coast Guard,the Occupational Safety and Health Administration (OSHA),or other international, federal, state, or local regulations mayalso apply. Such testing must b
28、e made at least every 24 hoursor more often when changing conditions warrant.When entering a compartment, another person shouldstand watch at the compartment entrance for the duration ofsuch entry to sound an alarm should an emergency occur.Normal safety precautions with respect to staging andladder
29、s are to be observed.2.8B.4 Tank Measuring EquipmentTank measuring equipment for the establishment of thereference gauge point location and reference gauge heightshall be as described in 2.8A.7.1 of API MPMS Chapter2.8A or 2.7.7.1 of API MPMS Chapter 2.7.2.8B.5 Measurement Conditions andTolerances2.
30、8B.5.1 MEASUREMENT CONDITIONSMeasurements should be taken only after all construction,conversion, and repair activities that would affect tank orreference height dimensions have been completed.Chapter 2Tank CalibrationSECTION 8BRECOMMENDED PRACTICE FOR THE ESTABLISHMENT OF THE LOCATION OF THE REFERE
31、NCE GAUGE POINT AND THE GAUGE HEIGHT OF TANKS ON MARINE TANK VESSELS11U.S. Department of Transportation. The Code of Federal Regulations isavailable from the U.S. Government Printing Office, Washington, D.C.20402.2International Maritime Organization, London, England.3National Fire Protection Associa
32、tion, 1 Batterymarch Park, Quincy,Massachusetts.2CHAPTER 2TANK CALIBRATIONThe area of the tank bottom directly beneath the referencegauge point must be a clean surface and free of scale, debris,and solid or semi-solid petroleum residues.When measurements for the reference gauge height aremade, the v
33、essel should be on an even keel with no trim orlist. If this is not feasible, a correction must be applied to themeasured gauge height to obtain the corrected referencegauge height as described in API MPMS Chapter 2.8A.2.8B.5.2 MEASUREMENT TOLERANCESMeasurement tolerances shall be as described in 2.
34、8A.8.2of API MPMS Chapter 2.8A or 2.7.8.2 of API MPMSChapter 2.7.2.8B.6 Number and Location ofReference Gauge Points2.8B.6.1 NUMBER OF REFERENCE GAUGEPOINTSIn the United States, all tank vessels fitted for crude oilwashing (COW) are required to have four hand gauging loca-tions in each tank, one of
35、which is to be located in the aftermostportion of the tank, as per U.S. Coast Guard regulations.Note: U.S. Coast Guard Regulations 33 CFR 157.128 (b) state (in connec-tion with design, equipment, and installation for COW), “Each cargo tankmust be designed to allow the level of crude oil in the tank
36、to be determinedby: (1) Hand dipping at the aftermost portion of the tank and three otherlocations; or (2) Any other means acceptable to the Commandant.”This wording is taken from Section 4.4.4 of Resolution of the Interna-tional Conference on Tanker Safety and Pollution Prevention, 1978 of theInter
37、national Maritime Organization.The regulations make no requirement that each of thesehand gauging points be calibrated for the total and incre-mental volume of the liquid in the tanks.Each tank on self-propelled tank vessels shall be fittedwith a minimum of two principal reference gauge points,each
38、fully calibrated for total and incremental tank volume.The additional manual gauging points are required by COWregulations. The reference gauge heights at these additionalhatches may be established for flexibility in measurements,for example, quantities remaining on board (ROB) and/oronboard qualtit
39、ies (OBQ). Nonself-propelled inlandwaterway barges may require a total of three calibratedprimary reference gauge points as covered in 2.8B.6.4.The location of the primary reference gauge points and theadditional secondary (manual) gauging points are covered in2.8B.6.2 for conventional tankships and
40、 in 2.8B.6.3 forCombination Carriers Ore/Bulk/Oil (OBOs).2.8B.6.2 LOCATION OF REFERENCE GAUGEPOINTS (TANK SHIPS)The two calibrated reference gauge points referred to in2.8B.6.1 should be located in each tank as follows.The primary reference gauge point may be located at thegeometric center of the ta
41、nk at deck level. This position willeliminate the effect of trim and list on the calculation ofstatic volumes when the vessel is in a loaded condition.However, if a swash bulkhead or transverse web frame isfitted at the mid length of the tank, the reference gauge pointmust be sufficiently forward of
42、 the mid length so that the zerogauge point clears the swash bulkhead or web frame at thebottom under the normal direction of maximum trim. Thislocation will permit obtaining an ullage for a quick closeapproximation of tank content volume without the necessity ofapplying a trim correction. For compl
43、ete accuracy, a trimcorrection is necessary inasmuch as the gauge point has beendisplaced longitudinally from the geometric tank center.The secondary reference gauge point or points on a vesseltank should be located at the aft and/or forward end of thetank, depending on the varying operating trim co
44、nditions.Note: In the course of normal operations involving a barge that operateswith trim by the bow and stern, the primary gauge point at the geometriccenter is not required since secondary gauge points are required at bothforward and aft locations.This gauge point should be located as close to th
45、e aft orforward bulkhead, centerline, or inboard bulkhead aspossible, but again sufficiently forward of same so that agauge tape suspended to take OBQ/ROB/free water measure-ments does not contact the bulkhead.The additional manual gauge points may be fitted at anyconvenient location in the tank whe
46、re there is a clear drop tothe bottom.The recommended fore and aft locations for the referencegauge points and the manual gauge points are shown inFigure 1. Figure 2 shows the same tank in a transversesection, indicating the necessity for clearance of the gaugepoint from the tank structures.The seco
47、ndary reference gauge point at the aft end of eachtank should be as far in board as possible so that if deadriseis present, the volume of cargo below the zero gauge pointwill be minimized. This is particularly necessary for wingtanks at the forward and aft ends of the tank space.Figure 3 indicates t
48、he recommended transverse locationsfor the reference and additional gauge points. With the usualconfiguration of tank structure, it may not be possible tolocate a primary reference gauge point at the geometriccenter of a center tank due to the presence of the centerlinedeck girder and the center ver
49、tical keel at the bottomrequiring the gauge point to be offset slightly to one side orthe other. For the wing tanks, there is usually no problem inlocating a gauge point at the mid width of the tank.All gauge points on all types of tank vessels must have aclear path from the reference gauge point to the zero gaugepoint clear of all interferences throughout the expected rangeof trim and list. This would include, without limitation,clearances from all structural framing members as alreadynoted, piping, ladders, heating coils, reach rods, and anodes.SECTION 8BESTABLISH
