Smoke detectors in plant rooms ???

[Benzerari]

Is there any one who knows the required distance by BS, between smoke detectors in a plant room full of (generators, large size of ducts and pipes that reaching the ceilings ...)?
In other words would that kind of obstacles stuff affect the radius distance of 7.5m of the smoke detector and 15m between smoke detectors?

Thank you in advance

Benzerari

[Graeme]

The detectors ideally should have 500mm all round clearance from large obstacles and walls.

Often not possible in plant rooms as there are so may pipes etc along the ceilings.

General to keep the detector twice the depth of the obstruction away if the obstruction is less then 250mm deep and less than 10% of the ceiling height. Any more it has to be 500mm away.

The radius of detection is unchanged by small obstacles but if you had a room small enough to be covered by one smoke detector but had joist that split the room in two and was deeper than 10% of the ceiling height,then you would need two.

[John Webb]

You also need to watch out for alterations in plant rooms after the building is completed.
1. They may lead to new equipment obstructing existing smoke detectors.
2. Alterations may cause unwanted alarms due to plumbing operations in particular. Either strictly control access to plant-rooms (difficult), institute 'hot-work' requirements even for small jobs, persuade plumbers to use push-fit fittings or put clear notices on every plantroom door along the lines of "This plantroom is fitted with automatic fire detectors. Contact.... before starting any hot work".

[Ashley Wood]

I would not use smoke detectors where generators are going to be fitted. New generators will give off smoke when they are first started due to oily finger marks left of exhaust and engine etc. Also, if someone left a rag on top of the generator in the future (it does happen) then again this would give you false activations. Alternatives are point type heat detectors (fixed temperature); heat detection cable strung over the generators, UV/IR flame sensors. One of the things to watch with point type heat detectors is the rise to high level of the ambient temperature once the generator has been shut down and the cooling fans and grills shut down and closed.

[Benzerari]

Thanks for every one, for your adds

The case of plant room we have is a huge one split to many parts with fire double doors, the ceiling is about 8 to 10m high, every day engineers have some service to do in generators, lift motors, and other machineries...as there are a lot…, it has 100s of detectors: opticals, ducts, flames, heat detectors..., to test them without a pole is just some thing very close to impossible.

To be honest, if we apply the standard of (the joist…. 10% from the floor..., 500mm far away in either sides of obstacle ...) in this plant room than we need 1000s of detectors throughout…shall we still have to consider this option regardless of the price?

Also some areas are just blocked off by big ducts, and there is no way to fit detectors on the ceilings without removing first the ducts, which may even cost more… shall we still have to consider this option regardless of the price too?

Thank you

Benzerari

[Graeme]

a bit confused.

you mention that your plant room already has hundreds of smoke detectors,flames,heat etc.

[Benzerari]

a bit confused.

you mention that your plant room already has hundreds of smoke detectors,flames,heat etc.

Yes, but 'they are not enough for that plant room', that is what I have mentioned in my service sheet when I did maintenance.

When the system was installed many years ago with the series 90 detectors, there was not all of that obstacles throughout (generators, ducts, pipes... and a lot of machineries), also the plant room have seen a lot of alterations in the last five years.

I do understand it is a bit confusing and not easy to decide about if you do not see it...

Thanks any way for your adds

Benzerari

[Allen Higginson]

Have you considered an aspirating system??

[Benzerari]

Aspirating system in plant room?  are you really serious ? it is a dusty and smoky area is it?

[Graeme]

They can be sensitivity adjusted.

Has your customer came back to you asked for extra coverage following your sm report?

[wee brian]

Aspirating systems dont have to be super sensitive, they can be pretty high tech these days - worth a look

I think you are being a little over pedantic, just because there are a few obstructions it doesnt mean that the detectors wont work, it could slow them down a bit but I doubt that will really matter.

[Allen Higginson]

Aspirating system in plant room?  are you really serious ? it is a dusty and smoky area is it?

As indicated in the posts previously if they are set up correctly they are suitable to a lot more enviroments than they used to be installed in (they also cut the cost of cabling and remember each sample hole is considered as a detector and so offers the same coverage and design options).

[Benzerari]

Thank you all for this bit of light that is really new to me.

Regarding the customers they have not yet been back to us, they usualy takes ages to get decisions agreed about... from their top management...

Thank you