New Water Mist Systems Guidance Published By The Welsh Government

The Welsh Government has published new guidance on water mist systems aimed at local authority building control and installers to assist compliance with building regulations.

Automatic water mist systems for domestic and residential premises was published on 27 August. This new guidance sets out how installers of water mist systems can satisfy the requirements of Regulation 37a of the Building Regulations 2010.

Automatic fire suppression is mandatory in new residential premises in Wales. New legislation in 2011 led to changes in the building regulations that came into force in 2013.

Building Control Bodies

The BRE was commissioned in January 2019 to write this guidance for the Welsh Government. It is primarily intended for use by Building Control Bodies to assist them in assessing water mist systems for new and converted domestic and residential buildings in Wales.

A water mist system is a fixed fire protection system, comprising components for automatic detection and actuation, water supply, delivery and water atomization. A water mist system discharges a spray of small water droplets from the operating nozzle(s).

evaluating water mist system design

Flow chart shows key stages in design, installation, and commissioning of a BS 8458 system

The guidance is also of interest to automatic water mist system manufacturers, designers, and installers as it details the essential information and supporting data required by Building Control Bodies. This guidance suggests when it may be appropriate to obtain independent specialist advice.

It contains a flow chart that shows key stages in the design, installation, and commissioning of a BS 8458 water mist system, the necessary communications with the Building Control Body and the key documents that the designer and installer will need to submit to the Building Control Body for the purposes of evaluating the water mist system design for the building.

Checklist of questions

There is also a checklist of questions for the designer, installer, and commissioner of the system to provide to Building Control Bodies confirming compliance with the installation standard.

This is not a regulatory document. The authors advise that it should be read in conjunction with BS 8458: 2015 (Fixed fire protection systems. Residential and domestic water mist systems. Code of practice for design and installation).