This test method covers the determination of the density or relative density of light hydrocarbons including liquefied petroleum gases (LPG) having Reid vapor pressures exceeding 101.325 kPa (14.696 psi). 

The prescribed apparatus should not be used for materials having vapor pressures higher than 1.4 MPa (200 psi) at the test temperature. This pressure limit is dictated by the type of equipment. Higher pressures can apply to other equipment designs. 

The initial pressure hydrometer readings obtained are uncorrected hydrometer readings and not density measurements. Readings are measured on a hydrometer at either the reference temperature or at another convenient temperature, and readings are corrected for the meniscus effect, the thermal glass expansion effect, alternate calibration temperature effects and to the reference temperature by means of calculations and Adjunct to D1250 Guide for Petroleum Measurement Tables (API MPMS Chapter 11.1) or API MPMS Chapter 11.2.4 (GPA TP-27), as applicable. 

Values determined as density or relative density can be converted to equivalent values in the other units or alternative reference temperatures by means of Interconversion Procedures API MPMS Chapter 11.5, or Adjunct to D1250 Guide for Petroleum Measurement Tables (API MPMS Chapter 11.1) or API MPMS Chapter 11.2.4 (GPA TP-27), as applicable. 

The calculations required in Section 11 shall be applied to the initial pressure hydrometer reading with observations and results reported as required by Section 11 prior to use in a subsequent calculation procedure (measurement ticket calculation, meter factor calculation, or base prover volume determination). 1.6 Annex A1 contains a procedure for verifying or certifying the equipment for this test method. 

The values in SI units are to be regarded as the standard. US Customary values shown in adjacent parentheses are for information only and may not be exactly equivalent. Both SI and customary units have been rounded so that they may not be exactly equivalent. 

This standard does not purport to address all of the safety concerns, if any, associated with its use. It is 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. 

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
 

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These intraconversion tables are applicable to all crude oils, petroleum products, and petrochemicals.

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This part provides standardized calculation methods for the determination of meter factors under defined conditions, regardless of the point of origin or destination or units of

measure required by governmental customs or statute. The criteria contained here will allow different entities using various computer languages on different computer hardware (or by manual calculations) to arrive at identical results using the same standardized input data. 

This document also specifies the equations for computing correction factors, including the calculation sequence, discrimination levels, and rules for rounding to be employed in the calculations. No deviations from these specified equations are permitted, since the intent of this document is to establish a rigorous standard.

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1.1 This standard describes the procedures for calibrating upright cylindrical tanks used primarily for the storage of petroleum liquids. It first addresses procedures for making necessary measurements to determine total and incremental tank volumes and then presents the recommended procedures for computing volumes.

1.2 Both SI (metric) and U.S. customary (USC) units are presented where appropriate in the document. SI and USC conversions may not necessarily be exact. The SI units often reflect what is available in commercial equipment.

1.3 The standard also provides guidelines for recalibration and for computerization of capacity tables.

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This chapter outlines the essential elements of provers that do, and also do not, accumulate a minimum of 10,000 whole meter pulses between detector switches, and provides design and installation details for the types of displacement provers that are currently in use. The provers discussed in this chapter are designed for proving measurement devices under dynamic operating conditions with single-phase liquid hydrocarbons. These provers consist of a pipe section through which a displacer travels and activates detection devices before stopping at the end of the run as the stream is diverted or bypassed.

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This chapter specifies the characteristics of stationary (fixed) or portable tank provers that are in general use and the procedures for their calibration. Guidelines are provided for the design, manufacture, calibration and use of new and/or replacement tank provers, and are not intended to make any existing tank provers obsolete. 

More specific design criteria are available in NIST1 Handbook 105-3, Specifications and Tolerances for Graduated Neck-Type Volumetric Field Standards (includes Provers, per Section 1.1 of NIST 105-3). Consideration must also be given to the requirements of any weights and measures authority that may be involved.

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This section of API MPMS Chapter 5 covers the unique installation requirements and performance characteristics of turbine meters in liquid-hydrocarbon service.

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1.1 This standard is applicable to custody transfer applications for liquid hydrocarbons. Topics covered are: 

a. Applicable API standards used in the operation of Coriolis

meters.

b. Proving and verification using both mass- and volume based

methods.

c. Installation.

d. Operation.

e. Maintenance.

1.2 The mass- and volume-based calculation procedures for proving and quantity determination are included in Appendix E.

1.3 Although the Coriolis meter is capable of simultaneously determining density, this document does not address its use as a stand-alone densitometer. See API MPMS Chapter 14.6 for this type of application. The measured density from the Coriolis meter is used to convert mass to volume.

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This publication describes the metering function of a LACT unit and is intended to complement API Specification 11N, Specification for Lease Automatic Custody Transfer (LACT) Equipment. LACT equipment includes a meter (either displacement or turbine), a proving system (either fixed or portable), devices for determining temperature and pressure and for sampling the liquid, and a means of determining nonmerchantable oil. Many of the aspects of the metering function of a LACT unit are considered at length in other parts of this manual and are referenced in 6.1.4.

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