CSA NGV 4.3:2018 pdf download.Temperature compensation guideline for compressed natural gas vehicle fueling
1.1 This Standard details the performance requirements for temperature compensation control used to prevent compressed natural gas (CNG) dispensing systems from exceeding a safe fill level of vehicle fuel storage container(s). This Standard contains safety performance guidelines for compressed natural gas fueling dispenser temperature compensation systems. It applies to field evaluation of existing dispensing systems designed primarily to allow for full fill and to avoid over-pressurization of vehicle fuel storage containers under operating temperature conditions as specified in this Standard.
This Standard applies to CNG fueling of vehicle containers with service pressures of P30 [20 700 kPa (3,000 psi)], P30HD [20 700 kPa (3,000 psi)], P36 [24 800 kPa (3,600 psi)], and P36HD [24 800 kPa (3,600 psi)]. P30HD and P36HD are designations used in accordance with CSA/ANSI NGV 1, and throughout the document the use of P30 and P36 are also applicable to P30HD and P36HD, respectively (see Annex A regarding applicable vehicle service pressures). This guidance does not apply to onboard vehicle temperature compensation systems or components.
This Standard is applicable to the dispensing of only natural gas that meets quality and interchangeability specifications contained in U.S. Federal Energy Regulatory Commission (FERC)-approved gas tariffs.
1.2 All dimensions used in this Standard are in metric units [International System of Units (SI)], unless otherwise specified. If a value for a measurement, as given in this Standard, is followed by an equivalent value in other units, the first stated is to be regarded as the specification.
If a value for a measurement and a corresponding value in other units are both specified as a quoted marking requirement, either the first stated unit, or both, are to be provided.
1.4 The requirements of this Standard are not intended to constrain innovation. When considering fuel compositions, controls, materials, designs, or constructions not specifically dealt with in this Standard, these alternatives are to be evaluated as to their ability to yield levels of safety and performance equivalent to or better than those prescribed by this Standard.
While temperature compensation is a critical function for CNG vehicles that regularly operate in hot climates, it is also important, and required in moderate and cold weather, to prevent over-pressurization as the gas in the container becomes hotter than the surrounding environment during fueling. The safety rationale for accurate temperature compensation is especially strong in many areas of the U.S. and Canada where wide temperature swings throughout the day and throughout the year are common.CSA NGV 4.3 pdf download.