Electrical Equipment in Proximity to Sprinklers - BS7671 Reg 512.2

All installations have to be designed. You have quite correctly spotted the 512 requirement for consideration of External Influences. Ask the contractor for the design information and how they are proposing to deal with the issue of the sprinkler installation. If they cannot answer the question or fail to produce a design in advance of installation then they are probably not a suitable contractor to use as they cannot meet the fundamental requirements of BS 7671 and the CDM Regulations 2015.

JP

Is the activation of fire sprinklers considered to be the normal/expected sort of environmental conditions we're expected to take into account?

If they did go off, they should saturate just about every surface, and I don't recall ever seeing IPX5 sockets or switches indoors in a building fitted with sprinklers. Even in a normal domestic we don't really take account of the roof springing a leak or a burst water pipe - which probably occur more frequently than sprinklers going off. Likewise if there is a fire, we might expect cables not to fall down prematurely, but we wouldn't expect a general installation to keep working normally.

My feeling is that if the building is on fire, a bit of water in a fitting is the least of your worries. Even in a building without sprinklers the fire brigade will be spraying water all over anyway, so I'm tending to think that just ignoring the sprinkler system might make sense.

   - Andy.

Also a fair chance that the light fittings may be combined and contain emergency lighting capability. If there is a fire and the sprinklers are going to operate then you are going to want the ELs to operate if the fire causes a loss of power.

JP

It seems an odd choice - lighting should be one of the last things to go off. Being a wall socket lightly drizzled on by the edge of the sprinkler distribution is one thing. Being in the line of fire seems foolish. I'd expect them to be spaced apart from the lights - in general sprinklers create a cone of spray facing down, and the light can just as easily be in the nearly dry zone between two of them.

Of course, except in films, or certain types of secure facilities, when properly set up, only the few sprinklers go off that are directly over or very near to the fire. So you do not want to kill lights to the floor while just the bin beside the under manager's desk is being drenched. The volume of water per point is modest - think 50 litres minute or so, only compares to the fire brigade hose once the whole floor is on fire and many are firing.  The flowing of the water automatically raises the alarm as soon as one triggers.

Mike

Hello,

Sprinkler activation would be abnormal and not expected during normal operation.

I also can't recall any installations that have IP rated infrastructure to respond to sprinkler activation.

It would be useful if the IET could produce a comment on this area of the wiring regulations.  

Thanks for your replies,

Richard

As an update the contractor has now proposed separate IP rated luminaires in the test cell area.  These will be static inverter / battery backed up to maintain a sufficient lux level during sprinkler activation.

Thanks,

Richard