Have your say on DZ 5442:2025 Specification for reticulated gas
This latest iteration of NZS 5442 provides an update to 2024’s interim standard, that now accommodates needs for hydrogen being brought into the gas network to further cement future-focused good practice.
Good practice built for tomorrow’s needs
With anticipated changes to the types of fuels we can expect to use in the future the standard acknowledges and accommodates blending renewable gases such as biomethane and hydrogen. Updated standards will help ensure that the gas is suitable for transportation, and safe to use in gas-burning appliances and equipment.
The draft standard, commissioned by Worksafe New Zealand – Energy Safety, has been developed by industry experts representing health and safety, plumbing, gas and electrical installation, gas and energy provision, geological science, and engineering. Now is your chance to review the draft and provide your own feedback before final publication.
DZ 5442 references a number of other New Zealand, joint trans-Tasman, American, Australian and international standards and other industry papers to form a basis built on global good practice.
It has also been created to help with quality monitoring and demonstrate compliance with New Zealand legislation, namely Gas (Safety and Measurement) Regulations 2010. With definitions and terminology outlined the standard covers biomethane types including landfill gas, agricultural waste and energy crops, wastewater or sewage and food waste. Further information is provided on safety and suitability for transportation and use, expected contaminants and combustion characteristics.
Technical details included
The word ‘natural’ has been dropped from the title of this standard, to reflect that blending other gases with methane-based gas in the network is an acceptable practice.
In this latest revision of the standard, Table 2 has been amended to reflect the new limit for hydrogen blending, and an informative Appendix G has been added, which gives details of what to consider when injecting hydrogen into the local distribution system (LDS) of the reticulated gas network.
While there are no specific limits on the level of biomethane that can be blended, the committee determined that blending hydrogen is restricted to injection within the LDS (< 20 barg) and limited to 10% maximum. The rationale for this requirement comes from a body of international research. The limits set by the committee are designed to remain within the range set by the Wobbe index parameters, while being consistent and aligned with hydrogen blending limitations in the latest revision of AS 4564, General-purpose natural gas. This standard specifies limits for gas characteristics and components that are consistent with safely operating the existing population of appliances.
DZ 5442 provides certainty for those who manufacture appliances for the New Zealand market, and for installers who set up these appliances. By specifying limits for contaminants, it seeks to ensure the integrity of transportation systems and prevent operating problems for most gas consumers.
Certain limits specified in this standard can be exceeded under certain circumstances without compromising safety, but this must be a matter for competent technical review, and specific to the conditions at the time. Exceeding the specification shall be accepted by the pipeline operator. Also, if a specified limit is exceeded, the pipeline operator’s required access conditions and interconnection agreements shall be adhered to.
In the previous interim edition of this standard (NZS 5442 (Int):2024), biomethane test methods and frequencies were suggested. Because biomethane was introduced, the limit for oxygen was relaxed and, relatedly, the limit for water was also reduced (see Table 2). Some gas consumers will require tighter limits on some listed or unlisted constituents, to support specific end uses (for example, to avoid poisoning catalysts). Gas consumers should meet these requirements by additional processing or through the contract with their gas supplier. Any such limits shall be technically justifiable and supported by appropriate methods to demonstrate compliance with this standard. If the limits are sufficiently general, they will be incorporated into this standard through the normal process for amending standards.
Now have your say
It’s important to remember that DZ 5442:2025 is a draft version, and should never be referred to as a standard, since content is subject to change following public consultation and before the committee has voted to approve content for publication.
Now is your chance to consider how DZ 5442 works for you and your industry needs. Review the draft document and provide feedback to help shape the final version – feedback may also include areas where you agree or support content. Deadline for comments submitted through the Standards New Zealand consultation hub is Monday 2 June 2025.
Have your say here: