PIR Controlled lighting - fire safety issues

[richjones]

For resons of energy efficiency, a university is considering the installation of ceiling mounted Passive Infra Red sensors to control lighting of the corridors and stairwells in teaching blocks and student residences. i.e. the lighting will only come on when movement is detected.
Does anyone have any information on how these systems perform in fire/smoke conditions. e.g. if smoke obscures the PIR sensors will:
a) the lights come on?
b) the lights go out -  plunging the corridors into darkness (therefore should maintained emergency lighting be installed to compensate?)
c) it be irrelevant as the smoke will have obscured the light fittings anyway?
d) it be irrelevant as people would be unwilling to evacuate through the smoke anyway?

[colin todd]

PIRs sometimes respond to fire. IR is not too attenuated by smoke but would not like guarantee as personally I dont know enough about security systems. At the stage that people are evacuatiing a student hall of residence the corridors should not be smoke filled and evacuation should always be possible-thats the point of the AFD and the fire doors. You could arraneg for the lights to go on when the fire alarm system operates, as happens in some public ents premsies with light dimming.

[Ken Taylor]

I've come across this in university residential areas before - unfortunately with some defective or badly positioned PIRs that meant that students would have to walk some way down a dark corridor before the lights came on.

With regard to emergency lighting and irrespective of whether the PIRs would work in smoke (regarding which I would have some reservations), if normal lighting fails and lighting is required for escape, seeing the signs, call-points, extinguishers, etc or for safe operation of machinery, use of hazardous chemicals and other risky things they can do in educational establishments that require adequate lighting, then it will need to be installed.

[wee brian]

If its non maintained lighting it will only come on when the circuit fails, not when the pir swithes the normal lighting off.

As it is i doubt that this will be a problem when the building is being evacuated but that's not the same as knowing for sure.

I've heard tell of a fire door (on a train) that opened in normal service via a pir. An ad hoc test showed that this door would also open in the event of a fire! (not ideal)

In the end they had to link some afd into the loop to disable the pir.

[colin todd]

Ah it was all so simple in the days of relays and rop flags wanst it Wee B.

[jane25]

Good enough for the fire service college, centre of excellence and home to the IFE, must be good enough for your university!!!

[wee brian]

Life certainly doesnt get any simpler Colin.

[colin todd]

Two errors janey dear. One the fire service college is only THINKS it is the centre of excellence. Its excellence is self proclaimed. Secondly, it is not home to the IFE. The Institution has been relegated to a corner of the FPA offices. Unfortunately, the membership are not told of the conditions in which the IFE staff have to work.Brian, Do you think we are getting old?

[wee brian]

As a wise man once said. "I wouldnt want to join any club that would have me as a member" - I've lectured at "the" college and you all know what a load of old tosh I come out with.

As for the IFE - think carefuly about who you vote for in the coming council elections.

Colin. You are already old. But I'm catching up fast.

[Brian Catton]

An interesting veiw of the Centre of Excellence. When I worked at the College, in the days that a Judge presided, I taught students how to instruct. I only taught them how to say it, not what to say.

Anyway back to the subject. We seem to forget that a PIR is only a switch. If that fails to bring on the lights and escape lighting is necessary surely the escape lighting would illuminate the escape routes anyway on failure of the primary sub circuit. I think I would be more concerned about Health and Safety issues facing a poor tired student returning home to a dark corridor and staircase after a hard night at the local library (or wherever).

[wee brian]

Brian. If its non-maintained lighting then it will only come on if the circuit fails. As you say the pir is a switch so the fact it turns the lights out is not a circuit failure.

I suppose you could provide maintained fittings in key locations such as the head of stairs etc but I am still not sure if this is a real or hypathetical problem.