ASTM_D_4738_-_90_scan.pdf

4Tb Designation:D 4738-90 Designation:MPMS Chapter 2.2B AnAmerkMNatbnalStandard I AMERICAN SOOIETY FOR TESTING AN0 MATERIALS 1816 Rm St.,Philadelphia.Pa.19103 Reprinted Imm lha Antiual Sook of ASTM Sladrrda.CopVright ASTM It nol liti&in the curreM comblrad index,will mrr In lb4 nrxt ediVan.Standard Practice for Calibration of Upright Cylindrical Tanks Using the Optical Reference Line Method This standard is issued under the fied designation D 4738;the number immediately following the designation indicates the year of original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.A superscript epsilon(6)indicates an editorial change since the last revision or reapproval.This practice has been approved by the sponsoring committees and accepted by the cooperating socieries in accordance with estal&shed procedures.I NOTE-Editorial corrections we&made in Table 1,Fig.3,and Fig.4 on Jan.5,1990.INTRODUCllON The optical reference line method(ORLM)is an alternative method to tank strapping for determining tank diameter.The primary difference between ORLM and the strapping method is the procedure for determining tank diameter at shell courses other than the bottom course.The optical reference line method provides for measuring a reference diameter on the bottom course by manual strapping and measuring deviations in tank diameter at other predetermined horizontal and vertical stations by using an optical device.Other required special measurements,procedures,methods,and analytical tools for the development of a tank capacity table are identical to those stated in API Standard 2550,Measurement-and Calibration of Upright Cylindrical Tanks.1.Scope 1.1 This practice describes measurement and calculation procedures for determining the diameters of upright welded(lap/butt)cylindrical tanks or vertical cylindrical tanks with smooth outside surface with either floating or fured roofs.This practice should be used in conjunction with API Standard 2550.There are a few occasions when there may be limitations to the application of the ORLM techniques described in this standard.Specifically,the use of the ORLM is not suitable for:1.1.1 Abnormally deformed(for example,severely dented or having visible signs of damage)tanks.These tanks are excluded from this practice and should be repaired prior to calibration.1.1.2 Outside measurement of insulated tanks,For appli-cation of ORLM,the insulation must be stripped,if possible.ORLM may be used on the interior of the tank;however,the reference circumference on the bottom course must be measured externally if possible,requiring the removal of insulation at the bottom course.This measurement shall conform to the procedures described in API Standard 2550.1.3 This standard may involve hazardous materials,oper-ations,and equipment.This standard does not purport to address all of the safety problems associated with its use.It is r This practice is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee DO2.02 on Static Petroleum Measurement.Current edition approved Sept.6,1989,and Jan.5,199O.Published December 1989.Originally published as D 4738-87.Lest previous edition D 4738-87.the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.1.4 The values in inch-pound units are the preferred units.The values in parentheses are for information only.2.Referenced Document 2.1 American Petroleum Institute Standards:API 2550 Method for Measurement and Calibration of Upright Cylindrical Tanks*3.Terminology 3.1 Dejinitions:3.1.1 Definitions listed in API MPMS Chapter 1,“Vocabulary”and Standard 2550 are applicable to this standard.In addition,the following definitions are relevant to ORLM:3.1.t.1 horizontal station-a pre-established location in the horizontal plane at ground level along the tank circum-ference.3.1.1.2 ofiet-the measurement observed through the optical device on the horizontal scale of the traversing magnetic slide at each vertical station.3.1.1.3 optical device-an optical plummet or a theodolite equipped with a precision level.3.1.1.4 reference circumference-the circumference of a ZAvailable from American Petroleum Institute,1220 L Street,NW,Washington,DC 20005.NOTICE:This standard has either been superseded and replaced by a new version or discontinued.Contact ASTM International(www.astm.org)for the latest information.A-H:ASTM D4738 90 W 0759510 0037373 L1=I D 4738 Horizontal Stations FIG.1 Plan(Shown for Eight Stations)tank measured by the strapping method on the bottom course very close to the reference offset location.3.1.1.5 reference e&the measurement observed on the horizontal scale of the traversing magnetic slide at the vertical station on the bottom plate.3.1.1.6 reference radius-the reference circumference di-vided by two?r wh