Sprinkler Services

Watermist Nozzle Testing

With watermist systems becoming increasingly popular for the protection of property, assets, and people against the risks of fire, regular third-party testing of watermist nozzles is vital to ensure your system will continue to do its job in the event of a fire.

In addition to offering UKAS accredited BS 8458 testing for residential and domestic watermist systems, our testing laboratory has the capability to undertake watermist nozzle testing for industrial, commercial, domestic, and residential systems.

Testing requirements

  • BS 8489-1:2016 requires industrial and commercial nozzles to be tested every 3 years.
  • BS 8458:2015 does not consider any requirements for regular nozzle testing of domestic and residential systems. The FPA recommends testing every 3 years in line with the industrial and commercial standard BS 8489-1:2016.
  • BS 14972-1:2020 requires nozzles of all system types to be tested every 5 years.

Some manufacturers may require their nozzles to be tested more frequently.

Test method

Once the nozzles are received at our test laboratory, they undergo the following tests:

Visual inspection

  • Appearance inspection of nozzles
  • Dimension inspection of nozzles
  • Thread inspection
  • Packaging and marking inspection
  • Serial number inspection

Function testing

  • Pressure and leakage inspection
  • Function test (operation of nozzle upon thermal activation)

Operation temperature testing

  • Nozzle placed into a water bath, heated at a rate of 0.5°C/min until nozzle activates

Flow testing

  • Flowrate inspection of nozzles
  • Pressure and K factor inspection
  • Spray pattern/angle inspection for any irregularities from the intended spray pattern

Download our fire research and testing brochure.


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