SNZ - NZS 4510
Fire hydrant systems
|Publication Date:||1 January 2022|
This standard covers fire hydrant systems for buildings, including external hydrant systems, for use by FENZ in accordance with its standard operating procedures.
It specifies requirements for the design, installation, commissioning, and testing of hydrant systems.
The standard is not intended to provide a standardised solution for all situations. Hydrants on a water supply authority's public networks are not considered as part of a hydrant system complying with this standard. Examples of buildings where this standard does not necessarily provide a detailed design solution include the following:
(a) Process plants;
(b) Underground infrastructure such as tunnels (road, rail, and infrastructure);
(c) Industrial process or plant buildings with exposed/open grate floors or platforms and gantries;
(d) Podiums and spaces such as external yard storage, external plants, and marinas.
(1) Guidance can be sought from international codes, standards, and data sheets to provide design criteria for such specialised risks.
(2) The location and design requirements for hydrant systems in these buildings should be specifically considered and agreed with FENZ during the design process. Refer to Appendix A.
The system's primary purpose shall be to allow water supplied by pumping appliances to the inlet to be reticulated to hydrant outlets within or externally to the building. The system inlets and outlets are located to facilitate and ensure reasonable levels of safety for firefighter operations. Where the pressure available from fire brigade pumps is not able to deliver the nominated flows at the hydrant outlets within the permitted pressure ranges, pumps shall be required to achieve those flows. It is necessary to ensure that the maximum allowable hydrant pressure is not exceeded.
Unless otherwise approved by the HSC, the system shall be a wet pipe system, charged and pressurised with water to ensure the integrity of the system and maintained in this condition. Where required by environmental conditions, the system could be a dry pipe system, charged and pressurised with air or nitrogen.
The water supply for firefighting shall normally be supplied by the fire brigade through the hydrant inlet from an available water supply.
This standard supports hydrant systems incorporating a permanently connected pressurised water source to enable hydrant use before the main supply is supplied by the fire brigade. This standard also supports combined fire hydrant and fire sprinkler systems. See Appendix B for guidance.
Staff use of hydrants
A secondary option is the reticulation of firefighting water for use by adequately trained and equipped personnel before the fire brigade arrives. In such cases, the hydrant system could be supplied with a permanently connected pressurised water source sufficient to allow staff to establish hose streams directly from the hydrant system outlets. Use of this secondary option shall not diminish the standard's primary objective.
Manually controlled branches
Hydrant systems complying with this standard are suited to firefighting operations using manually controlled branches (also known as nozzles).
Systems designed to this standard are not suitable for the use of automatic branches - that is, those which optimise flow rate in order to maintain a constant nozzle (branch) pressure.
Appendix C provides guidance on maintaining and altering systems installed to superseded editions of this standard.