BS 8458:2015 fire testing looks to examine the worst case scenarios. For determination of the worst case, the following criteria were used:
- Minimum number of scenarios where the spray head would have a visible line of sight to the fire (i.e. where inside of the “L” shaped barrier was visible to the spray head)
- Maximum number of tests where there would be a barrier between the 2 heads
- Maximum distance to fire loads for both the centre and corner fires
- Added exposure to the wind draught created by the fan
Both the centre wall locations were discarded as a result because they allowed for clear fire load visibility while having no impact from the fan used in the worst case scenario. The selection was then limited to the heads being placed 2m or 3m offset from the centre of the long wall. The 2m position is better placed for the centre fire tests but the 3m position is better placed for the corner fire. It is also much less susceptible to the fan given that the spray has its maximum velocity and momentum closest to the nozzle. Given that position, 2m would be less robust to the fan scenario independent of whether the worst case test was a centre fire or a corner fire, and this is a key factor of concern with water mist, this was chosen as the worst case scenario. The tests were then also run with the heads on the mirrored position. Finally, considering the last test scenario for the over 80sqm 'open room' test, the 2 nozzles were placed on the same wall given that one of the walls where the second nozzle would be placed is removed. This allows the required for fitting 2 nozzles to still be met and keeps the symmetry of the test room layout.
The total number of fire tests against BS 8458:2015 was therefore 11:
- 2 of each of the 3 fire load locations ( 1 for each spray head placement), subtotal: 6
- 1 worst case repeat with a fan for the worst case scenario of each head placement, subtotal: 2
- 2 open room tests for worst case scenario for each head placement (where one of the tests is redundant), subtotal: 3
For fire testing, a worst-case scenario was tested; 60m total hose lengths with 20m of 1⁄4” and 40m of 5/16”. This causes the longest possible delay in water output from the hose system.
The pump was then installed close to the head on the top wall so that it would be closest to the head that would tackle the obstructed fires which are the most difficult for Automist.
All the data gathered in these experiments demonstrated how the system operates and was used as a reference for the authoring of the DIOM (Design, Installation, Operation, and Maintenance) for Automist Smartscan Hydra.
We have also tested the system against numerous real-life scenarios.