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Fire Door stop size

Discussion in 'Building Regulations and Planning Permission' started by Jindigo, 20 Oct 2020.

  1. Jindigo

    Jindigo

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    Hi. Is there a bare minimum for a FD30 fire door stop. Is it 25mm or can this be reduced?
     
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  3. JohnD

    JohnD

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    You may get a better informed answer, but last time I got some, I looked it up and took advice, and the bigger stop is not needed if you have the intumescent strips with brush. These are easy to fit if you have a new door lining, difficult otherwise.

    I don't know if the brush is essential. It is also good for blocking draughts and noise.

    There is a Document which I don't have to hand.
     
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  4. Jindigo

    Jindigo

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    Thanks that's the info I have gleaned from various sourced. Just trying to maximise the clear opening. The doors in question are flat entry doors with the seals and brushes.
     
  5. Nakajo

    Nakajo

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    12mm thick x 25mm deep
     
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  6. frutbunn

    frutbunn

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    If memory serves me correct the 25mm deep stop is a throwback from the original British Standard for fire doors from 1947ish(?), which gave very specific methods of construction of the door and frame rather than a method of testing.
    Its subsequently been found to be unnecessary and again if my memory is correct, I believe it has been found to actually increase the passage of cold smoke by helping to "draw" the smoke through the frame.
    For information a door designated FD30 does not require cold smoke (brushes) seals, and in fact in some cases should not be fitted, ie protected domestic stairs where there is no detection in the rooms opening onto the stairway.
     
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  8. Jindigo

    Jindigo

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    Thanks for this.

    Can we reduce to 12mm if we only have intumescent strip? Fire doors inside the flat?
     
  9. frutbunn

    frutbunn

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    Assuming an FD30 is required then this will be OK to the internal doors.
     
  10. Jindigo

    Jindigo

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    Thanks!
     
  11. Nakajo

    Nakajo

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    Well that's 1 hour of CPD right there. Good to know.
     
  12. ^woody^

    ^woody^

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    Depends if its plant on or routed in the timber
     
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