UFSs

[nearlythere]

This is an extract from a website which lists 10 causes of false actuations of a FAS, this being one of them.

Chemical odours. Strong chemical odours like ammonia or paint fumes can set off a smoke detector. They don't like those heavy smells any more than we do, and they aren't afraid to complain about it.

I raise this as an engineer has advised a client that a false alarm was most likely caused by an exposed used paintbrush - used for the application of emulsion paint at that. I would initially suggest this is nonsense as fumes don't consist of airborne particles. Not, in this case,unless the paint was sprayed (which it wasn't).

What does the panel think of this?

[Bruce89]

Get the view of another specialist fire alarm engineer would seem a good place to start.

[Fishy]

I'm not a specialist, but I used to be responsible for 100s of fire alarm systems for well over a decade & I've never known one being set off by chemical fumes alone.  If the detectors are optical then I can't see the physical mechanism by which such 'fumes' would set it off  (unless it were sprayed of course).  Maybe it's feasible that ionisation detectors could 'see' certain otherwise invisible chemical species, though - will be interesting to see what others think?

Maybe try posting a query here: http://firealarmengineers.com/forum/index.php ?

[wee brian]

Or maybe ask the detector manufacturer?

[nearlythere]

On thinking about this more I realise that the installer and service engineer are general electricians and hence why they may spurt such utterances.

Same as when I recommended emergency lighting in a dental practice the client's general electrician asked him why he needed it when he has worked there for years and knows the layout well enough to get out in the dark.

Isn't it great we have such experts in plentiful supply!

[colin todd]

I like the smell of paint.

[wee brian]

Isn't it great we have such experts in plentiful supply!

Reminds me of my days as a BCO.  Bricklayers saying things like - "dunno why we need such a big beam, that'll hold a block of flats". I'd rather take the advice of a Structural Engineer, but Joe public is more likely to listen to Dave down the pub......

[lyledunn]

NT, detectors certainly can be triggered by chemical fumes. Light is bound to be distorted with fumes in the chamber. Following several activations of a fire alarm in a social club, the cause was traced to the tile cleaner used! Gent, the manufacturers, confirmed that their detectors could be so affected.

[nearlythere]

NT, detectors certainly can be triggered by chemical fumes. Light is bound to be distorted with fumes in the chamber. Following several activations of a fire alarm in a social club, the cause was traced to the tile cleaner used! Gent, the manufacturers, confirmed that their detectors could be so affected.

Thanks for that Lyle.

[kurnal]

Very surprised to read that Lyle. Though not doubting what you say for one minute  I would have expected the worst outcome from a dual optical device would be a pre alarm? And that the sensitivity or state of the detector could have been adjusted to eliminate unwanted alarms?

[Bill J]

I think it is likely that the words "Chemical Fumes" are being diplomatically used as a bit of a blunt instrument.

As an ex engineer and with about a dozen working for me, I can confirm that detectors are rarely set off by chemical fumes, however, I can confirm that the number of unwanted alarms does increased when the smell of paint is in the air, probably because of the builders/painters creating more dust, or disturbing dust which has settled within the detector (following building works),while removing and replacing the head, to paint a better finish. (and that does not include the builders works itself, or the painting of the detector).

Also "fumes" and "smells" are often an indication that something is airborne, with an analogue system it is normally simple to confirm the detectors reported condition, maybe swapping it with the room next door, to confirm it is airborne contaminants in the room.

A single paintbrush in a pot will not be the cause!

Bill

[Fishy]

I think it is likely that the words "Chemical Fumes" are being diplomatically used as a bit of a blunt instrument.

As an ex engineer and with about a dozen working for me, I can confirm that detectors are rarely set off by chemical fumes, however, I can confirm that the number of unwanted alarms does increased when the smell of paint is in the air, probably because of the builders/painters creating more dust, or disturbing dust which has settled within the detector (following building works),while removing and replacing the head, to paint a better finish. (and that does not include the builders works itself, or the painting of the detector).

Also "fumes" and "smells" are often an indication that something is airborne, with an analogue system it is normally simple to confirm the detectors reported condition, maybe swapping it with the room next door, to confirm it is airborne contaminants in the room.

A single paintbrush in a pot will not be the cause!

Bill

This reflects my experience as a 'user' of 100s of fire detection and alarm systems... I really don't buy the 'fumes alone' suggestion!