ISO/TC 28/SC 5 - Measurement of refrigerated hydrocarbon and non-petroleum based liquefied gaseous fuels

ISO 6578:2017 specifies the calculation procedure to convert the volume of liquefied petroleum gas (LPG) and liquefied natural gas (LNG) under the conditions at the time of measurement to the equivalent volume of liquid or vapour at the standard condition, i.e. 15 °C and 101,325 kPaA, or to the equivalent mass or energy (calorific content). It applies to the quantities of refrigerated hydrocarbon liquids stored in or transferred to/from tanks and measured under static storage conditions. Calculation of pressurized gases is out of the scope of ISO 6578:2017.

ISO 19970:2017 specifies minimum requirements to quantify the boil-off gas (BOG) consumed on liquefied natural gas (LNG) carriers for their own functions, notably for power generation, during cargo transfer operations. BOG in this document refers to the low molecular gas returned from shore tanks to ships' tanks and the gas produced in ships' cargo tanks. ISO 19970:2017 provides requirements for the metering of BOG and the subsequent calorific value calculations which can be taken into account when the energy transferred during cargo transfer is determined. This document also introduces performance requirements and calibration of the elements included in the BOG measurement system. A flowmeter of any type may be used to measure BOG as long as it meets the performance requirements specified in this document. ISO 19970:2017, with some modification, can also be applied to the measurement of BOG consumed by LNG carriers at sea.

ISO 29945:2016 specifies a manual sampling method for refrigerated liquefied DME at terminals in both loading and unloading ports along with precautions. ISO 29945:2016 does not include recommendations for the location of a sampling point in a line or vessel. ISO 29945:2016 is also applicable to the following cases, with necessary modifications: - sampling of DME on board liquefied gas tankers where appropriate sampling apparatus is provided; - sampling of other refrigerated, non-petroleum-based, liquefied gaseous fuels whose chemical and physical properties are similar to those of DME. The detailed chemical and physical properties of DME differ from those of LPG, which suggests that DME requires precautions different from those of LPG. However, their basic properties are similar to each other and so general reference is made in this document to precautions for LPG that have been applied in many countries. Reference can also be made to the appropriate individual items in this document for precautions concerning the quality.

ISO 10976:2015 establishes all of the steps needed to properly measure and account for the quantities of cargoes on liquefied natural gas (LNG) carriers. This includes, but is not limited to, the measurement of liquid volume, vapour volume, temperature and pressure, and accounting for the total quantity of the cargo on board. This International Standard describes the use of common measurement systems used on board LNG carriers, the aim of which is to improve the general knowledge and processes in the measurement of LNG for all parties concerned. This International Standard provides general requirements for those involved in the LNG trade on ships and onshore.

ISO 8311:2013 specifies a method for the internal measurement of membrane tanks used in ships for the transport of refrigerated light hydrocarbon fluids. In addition to the actual process of measurement, it sets out the calculation procedures for compiling the tank capacity table and correction tables to be used for the computation of cargo quantities. ISO 8311:2013, with some modification, can also be applicable to the calibration of independent prismatic tanks.

ISO 16384:2012 provides guidance on the practices for custody transfer of dimethylether (DME) on board ships, at both the loading and the discharging ports. It covers such aspects of volumetric calculation on board as measurement of liquid volume, vapour volume, temperature and pressure; and accounting for the total quantity of DME on board before and after loading/discharging, regardless of the type of ship's tank.

ISO 8310:2012 specifies the essential requirements and verification procedures for automatic tank thermometers (ATTs) consisting of platinum resistance thermometers (PRT) and an indicating device used for custody transfer measurement of liquefied natural gas, liquefied petroleum and chemical gases on board ships. Temperature detectors other than PRT are considered acceptable for use in the custody transfer service of liquefied gases if they meet the performance requirements of ISO 8310:2012 and are approved by national regulations.

ISO 18132-1:2011 establishes general principles for the accuracy, installation, calibration and verification of automatic tank gauges (ATGs) used for custody transfer measurement of liquefied natural gas (LNG) on board an LNG carrier or floating storage. The LNG described in ISO 18132-1:2011 is either fully refrigerated (i.e. at the cryogenic condition), or partially refrigerated, and therefore the fluid is at or near atmospheric pressure. ISO 18132-1:2011 also specifies the technical requirements for data collection, transmission and reception. Specific technical requirements for various automatic tank gauges and accuracy limitations are given in the annexes.

ISO 18132-3:2011 establishes general principles for the accuracy, installation, calibration and verification of automatic tank gauges (ATGs) used for custody transfer measurement of liquefied petroleum and chemical gases on board a gas carrier or floating storage. ISO 18132-3:2011 also describes the technical requirements for data collection, transmission and reception. Specific technical requirements for various automatic tank gauges and accuracy limitations are given in the annexes.

ISO 18132:2008 establishes the general requirements for the specification, installation and calibration/verification testing of automatic level gauges (ALG) used for refrigerated light hydrocarbon fluids, i.e., LNG and LPG, stored in bulk storage tanks on shore at pressures close to atmosphere. ISO 18132:2008 is not applicable to pressurized shore tanks.

ISO 8943:2007 specifies methods for the continuous and the intermittent sampling of LNG while it is being transferred through an LNG transfer line.

ISO 29945:2009 specifies a manual sampling method for refrigerated liquefied DME at terminals in both loading and unloading ports. ISO 29945:2009 also specifies detailed precautions to ensure safety during sampling work. However, safety measures, proposed for equipment being used for sampling, such as sampling lines and sample cylinders, are limited to general terms because they are governed mostly by national regulatory requirements. ISO 29945:2009 does not include recommendations for the location of a sampling point in a line or vessel. It is the responsibility of the user to ensure that sampling point is located so as to obtain a representative sample. However, to prevent vaporization of DME in the line before sampling, it is preferable to locate the sampling point at a place where the pressure and temperature of the DME in the line is kept constant to ensure obtaining a sample from the liquid phase only. ISO 29945:2009 is also applicable to the following cases, with necessary modifications: sampling of DME on board liquefied gas tankers where appropriate sampling apparatus is provided; sampling of other refrigerated, non-petroleum-based, liquefied gaseous fuels whose chemical and physical properties are similar to those of DME. The detailed chemical and physical properties of DME differ from those of LPG, which suggests that DME requires precautions different from those of LPG. However, their basic properties are similar to each other and so general reference is made in ISO 29945:2009 to precautions for LPG that have been applied in many countries. Reference can also be made to the appropriate individual items in this International Standard for precautions concerning the quality.

ISO 18132-1:2006 gives general requirements for the specification, installation and testing of level gauges used in the measurement of liquid levels on board ships carrying refrigerated light hydrocarbon fluids at close to atmospheric pressure (mainly LNG/LPG).

Specifies the essential requirements and verification procedures for float-type level gauges (including those operated by servomechanism) for ship and shore tanks.

Also sets out the calculation procedures for compiling the calibration tables to be used for the measurement of cargo quantities. Annexes B to F give calibration uncertainty and examples of main gauge table at - 160 °Celsius, trim correction table, list correction table, and correction table for tank shell expansion or contraction.

Specifies the calculations to be made to adjust the volume of a liquid from the conditions at measurement to the equivalent volume of liquid or vapour at a standard temperature and pressure, or to the equivalent mass or energy (calorific content). Annexes A to H form an integral part of this standard.

Describes the sampling system, the apparatus, the sampling procedure, and the contents of the sampling report. Gives precautions. Specifies 15 terms and definitions. Annex A is for information only.

Specifies the essential requirements and verification procedures for sensors, thermocouples and associated equipment to be used for ship and shore tanks containing hydrocarbon fluids. Annexes A and B are for information only.

Specifies the essential requirements and verification procedures for capacitance-type liquid level gauges to be used for ship and shore tanks containing hydrocarbon fluids. Annexes A and B are for information only.

Describes a stereo-photogrammetric procedure for the internal measurement of spherical tanks. Lays down the calculation procedures for compiling the calibration tables.

Includes a method for the internal measurement of thanks used for the transport. In addition to the actual process of measurement, it sets out the calculation procedures for compiling the calibration table and correction tables to be used for the computation of cargo quantities. Definitions are given.