6.5 Hydraulic Calculations

Hydraulic calculations are a key requirement to ensure that at least the same amount of water will be delivered “in situ” as validated during the fire tests detailed in Annex C.  We must consider that (as per 6.6) more than 2 nozzles will operate and the piping must have an adequate diameter to supply the water demanded. Hydraulic calculations take into consideration the pressure losses due to pipe lengths and fittings so that adequate diameter piping is utilized between the pump and the “least favourable nozzles”.

Automist Hydra is a pre-engineered system with a maximum total hose length of 60m. This means that for this limited hose length, the calculation has been made by the manufacturer and therefore it does not require hydraulic calculations.  Diameters of hoses that can be used by installers are limited to ¼” and 5/16” only, and lengths to 60m.  Longer hoses would result not only in excessive pressure loss but in excessive time for “hose filling” and therefore, compromised fire performance.


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