This standard covers the level measurement of liquid hydrocarbons in stationary, aboveground, atmospheric storage tanks using automatic tank gauges (ATGs). The standard discusses automatic tank gauging in general, accuracy, installation, commissioning, calibration, and verification of ATGs that measure either innage or ullage. It covers both intrusive and non-intrusive ATGs used for either custody transfer or inventory control. The standard also covers the requirements for data collection, transmission, and receiving.

This standard does not cover the following:

a) Hydrocarbons having a Reid vapor pressure above 15 pounds per square inch (in.) absolute (100 kPa).

b) Measurement of weight or mass with ATG equipment. This is covered in Chapter 3.6 and Chapter 16.2 of the Manual of Petroleum Measurement Standards.

c) Measurement of the level in underground tanks or in pressurized tanks storing liquid hydrocarbons.

d) Conversion of the tank level to liquid volume this is covered in Chapter 12.1 of the Manual of Petroleum Measurement Standards.

e) Measurement of temperature, sampling, density, and sediment and water (S and W), which are discussed in Chapters 7–10 of the Manual of Petroleum                 Measurement Standards.

Safety and material compatibility precautions should be taken when using ATG equipment. Manufacturers’ recommendations on the use and installation of the equipment should be followed. Users should comply with all applicable codes and regulations, API standards, and the NFPA National Electrical Code.

 This standard is available for purchase at the API Publication Store: https://www.apiwebstore.org/standards/3_1B

This standard describes the following:

a) the procedures for manually gauging the liquid level of petroleum and petroleum products in nonpressure fixed-roof, floating-roof tanks and marine tank vessels;

b) procedures for manually gauging the level of free water that may be found with the petroleum or petroleum products;

c) methods used to verify the length of gauge tapes under field conditions and the influence of bob weights and temperature on the gauge tape length; and

d) influences that may affect the position of gauging reference point (either the datum plate or the reference gauge point).

Throughout this standard the term petroleum will be used to denote petroleum, petroleum products, or the liquids normally associated with the petroleum industry.

This standard is applicable for gauging quantities of liquids having Reid vapor pressures less than 103 kPa (15 psia).

The method used to determine the volume of tank contents from gauge readings is not covered in this standard.

The determination of temperature, density, API gravity, and suspended sediment and water of the tank contents are not within the scope of this standard; however, methods used for these determinations may be found in the API Manual of Petroleum Measurement Standards (MPMS).

This standard can be purchase via the American Petroleum Institute (API) webstore: https://www.apiwebstore.org/standards/3_1A 

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.

This standard can be purchase via the American Petroleum Institute (API) webstore: https://www.apiwebstore.org/standards/12_2_4  

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.

This standard can be purchase via the American Petroleum Institute (API) webstore: https://www.apiwebstore.org/standards/4_2 

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.

This standard can be purchase via the American Petroleum Institute (API) webstore: https://www.apiwebstore.org/standards/4_4  

This standard can be purchase via the American Petroleum Institute (API) webstore:  https://www.apiwebstore.org/standards/5_2

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

This standard can be purchase via the American Petroleum Institute (API) webstore: https://www.apiwebstore.org/standards/5_3