NZS 5259 Gas measurement has been revised to bring it up to date and relevant to gas measurement systems for fuel gases, as defined in the Gas Act 1992, and for the conversion of measured volume or mass to energy.
In revising the standard, the committee considered current best practice as laid out in relevant national and international standards, new and developing technologies, compliance costs, and generic development such as electrical metering.
Among the key changes are:
- sections of the previous 2004 standard have been rearranged. Section 1 now provides general information about the standard, section 2 contains performance requirements for the gas measurement system), and section 3 sets out a means of compliance for gas measurement. Appendix C (compliance checklist) has been amended to align with the relevant clauses in section 2.
- the performance requirements have been reviewed and updated to ensure that all of the existing regulatory requirements for accuracy and suitability have been incorporated. These have been extended as necessary to apply not only to the meter and conversion device but also other components of the gas measurement system. Worker competency requirements are also included.
- meter test intervals have been amended to align with international standards and manufacturers’ specifications. The amendments reflect current technologies and measurement methods.
- AS/NZS 4944:2004 Gas meters - In-service compliance testing is referenced as a means of complying with requirements for statistical sampling of meters with a capacity of G16 and smaller. As a result, the previous Appendix L on statistical sampling has been removed.
- the permissible weighted mean error for acceptance testing of meters with capacity greater than G160 is amended to match current best practice. Meters of capacities G6.5 and G16 are combined to align with AS/NZS 4944:2004.