BS 8458 states in its introduction that ‘the testing and approval of watermist system components for residential and domestic applications is a developing area’. As per FM 5560-2017, page 16:
“Due to the current state of water mist system technology, a comprehensive absolute standard for the testing of water mist components is not possible. Since each water mist system is unique in its operation and design, the component testing of the water mist system shall be performed on a case-by-case basis.”
We have had to venture to the US and engage with UL to develop component testing for an electronic nozzle, as there was no certification available in the UK. Also BS 8663 does not cover electronically controlled watermist nozzles.
Our internal testing has followed the standard UL 2167 “Water Mist Nozzles for Fire Protection Service” where we have selected which tests we would expect to be applied by UL at the time of certification. The rationale for considering the test applicable, or not, is explained below:
6 - General Construction (6.2 and 6.5 not applicable as electronically controlled nozzle)
7 - Strainer and Filter (prescriptive, included in design)
8 - General Performance: (In section 8.4, only the Residential - Section 44 - tests are being targeted)
9 - Watermist Nozzle Requirements
10 - Exposure Tests on Nozzles Incorporating Polymeric Gaskets: Tests to be carried out on a-rings used on assembled system (pivot and nozzle)
11 - Nominal Operating Temperatures: Not applicable as open nozzle has no thermosensitive element, however, detectors used on system should be certified
12 - Operating Temperature Test: Not applicable as open nozzle has no thermosensitive element, however, detection must be certified so that RTls are within expected ranges.
13 - Water Flow Test: run internally
14 -Water Distribution Test: Not applicable due to horizontal nature of spray targeting
15 - Water Droplet Size and Velocity: Positions need to be customised for the horizontally oriented, 65° vertical spray fan, so that nozzle changes can be shown to provide equivalent spray characteristics.
16 - Function Test: Not applicable as nozzle does not contain the heat-sensitive element and does not have a protective cover that has to be released
17 - Deflector/Orifice Assembly Test: Not applicable as not present in Automist assembly.
18 - Body Strength Test: No components well suited for this assessment with relevant failure mode, not applicable
19 - Strength of Glass Bulb Elements: Not applicable for electronic nozzle
20 - Strength of Fusible Elements: Not applicable for electronic nozzle
21 - Leak Resistance: Not applicable to electronic nozzle
22 - Hydrostatic Strength: run internally
23 - Heat Exposure: Not applicable for electronic nozzles
24 - Thermal Shock: Not applicable to electronic nozzles
25 - Corrosion Tests: not considered required as application is only domestic and wet parts construction is of 316 stainless steel
26 - Integrity of Nozzle Coatings: Not applicable as no coating is used on nozzles
27 - Water Hammer: Not applicable for electronic nozzles
28 - Dynamic Heating: Not applicable to electronic nozzles
29 - Plunge Test: Not applicable to electronic nozzles
30 - Prolonged Plunge Test: Not applicable to electronic nozzles
31 - Heat Resistance: run internally (fire under the nozzle)
32 - Vibration: run internally a, b and c
33 - Rough Usage Test: not applicable as every spray head is packaged individually and not in boxes with multiple nozzles
34 - Impact Test: run internally
35 - Lateral Discharge: Not applicable for electronic nozzles without any thermosensitive element
36 - Thirty-Day Leakage Resistance: Not applicable for electronic nozzle
37 - Vacuum Resistance: Not applicable for electronic nozzle
38 - Clogging Test: run internally
39 - Freezing Test: Not required for a domestic electronic nozzle that contains no water in stand-by condition
40 - Shipboard Machinery Space Fire Tests: Not applicable for Automist's residential application
41 - Shipboard Passenger Cabin Fire Tests: Not applicable for Automist's residential application
42 - Shipboard Passenger Cabins Greater than 12 m2: Not applicable for Automist's residential application
43 - Shipboard Public Space Fire Tests: Not applicable for Automist's residential application
44 - Residential Area Fire Tests: See BS 8458 Compliance
45 - Light Hazard Area Fire Tests: Not applicable for Automist's residential application
46 - Ordinary Hazard Group 1 Fire Tests: Not applicable for Automist's residential application
47 - Ordinary Hazard Group 2 Fire Tests: Not applicable for Automist's residential application
48 - Production Leakage Test: Not applicable for electronic nozzle
48A - Glass Bulb Integrity Test: Not applicable for electronic nozzle
49 - Design and Installation Instructions: See DIOM
50 - Water Mist Nozzle Marking: not certified so requirements does not apply.
A spray head swivel durability test has also been completed on Smartscan hardware to verify how many scans the spray head would perform before failure. Hydra completed up to 70,000 cycles, well over the expected lifetime requirement.
Further details on the component testing are available on request.
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