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Thread: Egress lights

  1. #1
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    Egress lights

    My battery backup egress lights have photocells, they will not come on if the building looses power during daylight, is this a problem by any code?

  2. #2
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    That is how 99%+ of such units work, they operate on loss of normal power and do not sense whether there is sufficient ambient light or not.

  3. #3
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    So the fire Marshall shouldn't care if he does not see them lit? I only ask because I specifically remembering one making a big deal out of one not working

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    I'm sorry such a simple description in OP and I still misunderstood it. I was only thinking of typical battery operated emergency egress lighting. OP says there are photocells and they don't come on when there is ambient light. Can't recall ever seeing such a thing, but still don't see that it should be an egress problem if there is sufficient ambient light.

  5. #5
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    I don't think it would be allowed by both the IBC or NEC. In the NEC see 700.12(F) and 701.12(F)
    (4) A relaying device arranged to energize the lamps automatically upon failure of the supply to the unit equipment

    An electric eye would prevent the lamps energizing automatically I'm guessing that they figure that is just one more thing that could go wrong and emergency lights are so rarely used it would not be a real energy saver compared to the risk.
    Rick Napier
    Inspector and Instructor

  6. #6
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    Quote Originally Posted by RICK NAPIER View Post

    An electric eye would prevent the lamps energizing automatically I'm guessing that they figure that is just one more thing that could go wrong and emergency lights are so rarely used it would not be a real energy saver compared to the risk.
    Makes sense.
    Most the emergency exit lighting systems we put in were in cinemas. There would be very little or no ambient light. Slightly off topic, but the UPS systems had to have a 3-hour autonomy. Three hours to evacuate a cinema???

    But that was the cinematographic code that they applied. Good for us I suppose - it meant fairly large systems.
    Si hoc legere scis nimium eruditionis habes.

  7. #7
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    Quote Originally Posted by Besoeker View Post
    Makes sense.
    Most the emergency exit lighting systems we put in were in cinemas. There would be very little or no ambient light. Slightly off topic, but the UPS systems had to have a 3-hour autonomy. Three hours to evacuate a cinema???

    But that was the cinematographic code that they applied. Good for us I suppose - it meant fairly large systems.
    Did you put backup power to the machine room? Might need three hours to finish watching the show and still have enough power for egress lighting afterwards

  8. #8
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    Quote Originally Posted by kwired View Post
    Did you put backup power to the machine room? Might need three hours to finish watching the show and still have enough power for egress
    lighting afterwards
    The backup powered only the emergency egress lights.
    Si hoc legere scis nimium eruditionis habes.

  9. #9
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    I suppose I could have been more clear, power comes in to a battery backup inverter, then goes to the ipro/ watt stopper relay (flaw by design I think) then to the fixture which has a photocell built in, so if the watt stopper had the lights off when the power went out they would never come on anyway, even bypassing the relay or assuming the watt stopper was programmed to have the lights on, it still would not light during the day

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