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Emergency lights - which circuit

Discussion in 'Electrics UK' started by RF Lighting, 2 Oct 2019.

  1. RF Lighting

    RF Lighting

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    I’m currently rewiring one section of a community centre. To the rear of the building is an external fire escape which is served by two doors from the building.

    The lighting in each room where there is an escape door is supplied from a different distribution board.

    I am proposing to install four external fittings to light the staircase. One above each door, and two on the longer lower section.

    Would you prefer the lights to be fed from a local circuit per floor, or all from one circuit only? If only one circuit, which would you use?

    Here’s a picture of the fire escape with the two doors circled.

    340D647E-54C3-4BFE-9C4C-D5EED29291EF.jpeg
     
  2. securespark

    securespark

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    I think I would be tempted to use a local circuit for each run.
     
  3. AdrianUK

    AdrianUK

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    Run the fittings in maintained mode? Then they will always be lit hence you are covered by the "operating when the local lighting circuit fails" clause
     
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  4. JohnW2

    JohnW2

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    More than one circuit is 'safer', isn't it - just in case of the (hopefully unlikely) scenario of one circuit and some or all of the battery back-ups failing at the same time? Although that's a very unlikley scenario, looking at things the other way around, I can think of no reason (except perhaps one-off convenience during installation) for favouring a single circuit - so 'why not?' multiple ones, 'just in case'?

    Kind Regards, John
     
  5. Adam_151

    Adam_151

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    How is the fire esape lit normally? i.e. when theres no power failure?

    To be compliant they should be off the circuit providing the normal illulination to that area, but I cant see any in the picture, so making them maintained might be the answer, possibly switched maintained off a photocell.

    Normal bulkheads mounted to the wall will probably not provide adequate illumination on the treads; most of the light is thrown outwards rather than down.


    Most in your position would install non maintained bulkheads off the local lighting circuits in the room the other side of the fire exit
     
  6. Harry Bloomfield

    Harry Bloomfield

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    Maintained, because a fire might occur during the hours of darkness and the circuit might remain live - so no lighting on the fire escape at all.
     
  7. RF Lighting

    RF Lighting

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    This has given me some good ideas. Currently the only lighting on the fire escape is provided by two 8W fluorescent bulkheads which you can just see in the picture. One above the door on the first floor and one directly below above the first floor window. There is no lighting at all for the second floor exit.

    The existing lights are switched by a two way switch, one at each door which provides a 230V AC switched supply to the lights, and the emergency supply is 24V DC from a central battery located in a remote part of the building fed from a different dist board on a different phase, so obviously not ideal. The 230V electronic ballasts do not function so currently there is no light at all on the stairs unless there is a building wide power failure.

    I’m wondering if to try and re-use the existing switching arrangement or if a photocell would be better?

    I had been thinking today that standard LED self contained bulkheads would not actually throw much light at all onto the treads. Is there a more suitable fitting?
    I’ve been thinking about using standard bulkheads mounted on L brackets so all the light is projected down onto the treads just to try and keep costs down.

    Thanks for all the replies so far.
     
  8. RF Lighting

    RF Lighting

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    680E3D64-780A-43CE-9EF7-6450D90EB69D.jpeg


    I’ve circled the existing emergency lights in blue. The light circled in green is just a standard outside light with no emergency supply at all, so this staircase is not protected.

    Also the cellar door has no lighting at all. It is not a designated fire escape but it really needs to be as it is the only other escape from the mains and boiler rooms other than the main internal staircase.
     
  9. 333rocky333

    333rocky333

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    The purpose of the one outside the door is so in an emergency you dont go out into darkness, so if not using Maintained lights, i would say the one outside each exit should be on the same circuit as the exit sign on the inside of the door
    Edit
    Just noticed the internal ones are on a Dc system
     
  10. RF Lighting

    RF Lighting

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    The master plan is to eventually ditch the DC system completely in favour of local self contained units, but this is a big building. It is an ex council building which is now run as a charitable trust under the community asset transfer scheme so cost is a big factor in all the work carried out there.
     
  11. Adam_151

    Adam_151

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