1. Scope

BS 8458 has a clearly defined scope:

‘recommendations for the design, installation, water supplies, commissioning, maintenance and testing of watermist systems with automatic nozzles installed in residential and domestic occupancies’.

It defines automatic nozzles as:

‘Automatic watermist nozzles operate at a pre-determined temperature to discharge water over a known area below. The flow of water thus initiated causes the sounding of an alarm. Only those watermist nozzles operate which are individually heated above their operating temperature by the heat from the fire.’

The standard was produced with the commonly used mechanical automatic nozzles in mind. We are working with the relevant BSi working group to expand the scope of the standard to include electronically controlled nozzles. Standards are meant to be expressed in terms of performance rather than design or descriptive characteristics to not limit anticompetitive effects or impede innovation. However, unfortunately, this was not considered when the standard was first created.


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