Pipe boxes

[Graeme]

Gents

I have been at a site today of a large old premises which is upgrading the fire alarm system. Having looked round the building i have noticed a few large pipe boxes that run from the ground floor,all the way to the top third floor.

Is there any requirement for pipe boxes that penetrate more than one floor? i.e fire stopping etc. and do they have to be over a certain size to be considered. Never really given pipe boxes much thought until today.


Thanks

[Allen Higginson]

Are these for your bagpipes?

[Graeme]

erse   

to be sure to be sure

[Graeme]

obviously a daft question then..

[Allen Higginson]

obviously a daft question then..

Are they sort of like small flues with pipes in them running vertically??

[Graeme]

just pipe boxes in general really. The ones at this site run from ground floor to attic with big holes in each floor with no fire barriers.

[Wiz]

Graeme, I would suggest that if they are not fire stopped then they will be treated as any riser i.e detector at the top and a detector within 1.5m of any openings to it on each floor.

Your description of what you've got sounds like a real fire risk; Openings between floors, openings onto floors, and all leading to an attic!!!! Surely, this is just providing any easy route for the spread of smoke and flames between floors? I would imagine it should be properly fire-stopped. But if it can't then the detectors mentioned above must surely be a certainty.

[Allen Higginson]

What grade of system is going in G?

[Graeme]

Thanks Wiz.

The pipe box in this building is pretty common in alot of places and i have never really given them much thought but they do mostly all go from top to bottom usually after a central heating install.

They are all boxed in by wood so they don't really have any openeings at any levels but the holes through the floor are never fire stopped. There are also the type that are flush with the wall but again run through all floors.

Most are usaully packed with pipes or cables so fitting a detector in them would impossible and would asd be ott?

So in a nutshell do pipe boxes have to be over a certain size to be considered as a flue or rise if unstopped?


Al- it's an L1 to compensate for a lack of fire barriers throughout.

[kurnal]

It all depends on the floors through which they pass.
If they are compartment floors they MUST be fire stopped to the same fire resisting standard as the floor. Approved document B3 gives explanation of when compartmentation is required, the degree of fire resistance  and details of permissible penetrations through compartment floors. Though it applies to new build its a good benchmark. The passive fire safety industry makes a whole ancge of fire stopping devices and pipe collars etc for use in these circumstances.

If you can give us some indication of the uses to which the building is put  ie shop office factory residential, car park warehouse  etc, its size and height of the top floor and details of any basements we could give you a pointer.

Irrespective of fire compartmentation requirements it would be madness not to fire stop the duct at each floor level as otherwise there is a likely total loss as a result of a small fire. There are many fire stopping products on the market that can be easily installed and can be removed for future changes.

[GregC]

Fire rated Expanding foam is idea for this, just make sure the cable sheaths are not going to be affected.

Under a certain size the riser can be ignored as long as it is fire stopped as per Kurnals reply

[David Rooney]

Along similar lines... is the fire stopping applicable in "big" risers... eg. the type fitted with a fire door, where you can walk on a solid concrete floor and then find along one wall a purpose made hole cast in the concrete with cable trays etc passing though from basement to Nth floor....?

[nearlythere]

Problem I am encountering at present is vertical flues at all levels of 5 storey block of flats and kind of fire stopped between floors. Within vertical flues are gas consumer units and associated pipework including plastic water supply pipework to each flat. An attempt has been made to fire stop with painter calk, tile grout, expanded foam, silicon of various colours and rockwool. These are used to fire stop the plastic water pipework which Ts off below floor level to groups of flats on each floor.
Talk about builders wanting to get in and out quickly.
Is there a product which can be used for a row of vertical water pipework.

[kurnal]

Along similar lines... is the fire stopping applicable in "big" risers... eg. the type fitted with a fire door, where you can walk on a solid concrete floor and then find along one wall a purpose made hole cast in the concrete with cable trays etc passing though from basement to Nth floor....?

In such a case Dave the duct is a protected shaft- a bit like a lift shaft or staircase running vertically though the building.
If for example the height of the building justifies a one hour compartment floor, a compartment can be linked to another using a protected shaft. The walls will be fire resisting to the full one hour standard and doors to half of this standard. This is because to penetrate the compartment a fire would have to break through two fire resisting doors. Protected shafts can therefore be open within the shaft from top to bottom. But it is very mportant to ensure that the doors can resist fire from both sides and for example the gaps between wall and door frame on he inside of the shaft are infilled,

If you dont provide a protected shaft you have to fire stop all the penetrations at floor level (there are permitted exceptions for some pipes). There are many products available, mineral fibre backed up with a skim of plaster of paris both sides is very common and easily maintaiend and replaced.

[David Rooney]

Thanks Kurnal.... you're my rock.......!!