Smoke detection in ceiling

[Paul1979]

Hi All,

Quick question - we have a building (sleeping risk) where there are differentiating ceiling heights. Lowest part of the ceiling is 3m but the highest point is 6m (with an apex point).

The fire alarm installers have only placed smoke detectors on the lower ceiling levels, but have left the higher ceiling levels with no coverage.

Am I right in thinking that for an L1/L2 system, there must be smoke detection on both ceiling levels, including the top 600mm of the apex point??

I have read the Apollo Guide for BS5839-1 but just wanted to check my interpretation was correct?

Thank you as always for all your help and advice.

Happy Easter!

[Messy]

Hi Paul

I must stress I am not a fire alarm engineer, designer or frankly am I competent in FD design - neither have I access to BS 5839-1 any more, but I have got some notes that I used to keep with me for reference

My understanding is for a small apex of up to 600mm in height, you can treat the ceiling as flat

For a 600mm and higher apex, the smoke detection should be placed at the highest level - not withstanding the risk of stratification at the peak of an apex



More on P32 here re sloping ceilings
More on P52 on stratification

https://marlowefireandsecurity.com/wp-c ... k-2018.pdf

Good luck

[Paul1979]

Thanks Messy, much appreciated as always.