Smoke alarms that detect smoke

Tom Lewis

Tom Lewis

Joined
Feb 24, 2000
Messages
1,924
Like most I have several smoke alarms in my shop. They are a real nuisance. They detect dust and sound off. I have one outside under a shed by my dust vacuum and this evening we got a lot of rain and it sounded off.
I have one about 20 feet away from my propane forge, but when I forge Damascus it sounds off.
Is there any smoke alarm that just detects smoke.
 
There are TWO types of smoke detectors. Photo and ionization. Photo basically looks for slow smoldering fires. It works with a simple photo cell looking for light (think photo cell for dusk to dawn lights) . If smoke or dust enters the chamber it reflects so the photo cell detects light. There is actually a light in a dark chamber and photo cell looking for light that it never sees unless smoke or dust reflects it.

Ionization looks for fast burning flames. Both false alarm. Photo with dust and ionization with chemicals say aerosol, cleaners etc.

And then there's a third type that does BOTH!

A commercial or residential home security fire alarm system is way more tolerant that the standard home variety.
 
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Depending on your shop layout and type of building, another type of detector may work. Thats a photoelectric beam type smoke detector. These things are widely used to protect factories, malls, theatres, and so on.
Mounted near the ceiling, Works by transmitting a infrared light beam across the room to a reciever. Its designed to respond to a slow blockage of the light beam.
Some versions, transmitter and reciever are combined in the same housing, the light beam projects across the ceiling to a reflex reflector to come back to its reciever. But the same thing, A gradual decrease of reflected light is recognised as smoke.

If something abruptly blocks its lightbeam, thats alerted as a trouble condition. Not a fire. Its just to get you to fix whatever fell across the beam.
 
For the one that's by your shop just put a shower cap with a big red remember to remove banner over it.

Most smoke alarms come with a cover meant for that now.
 
I had as similar issue with the smoke/fire alarm in my house. The one near the kitchen would go off when cooking or baking. I changed it for a new unit and it was much better, but still would go off when charring steaks of hot-searing things in a big skillet. I ordered a cover to stick over it when cooking. It is red with a long plastic ribbon dangling down 3 feet. Exterminators use these to cover the alarms when fogging a house.
 
Most of the covers are nothing but a red shower cap. The elastic edged bowl covers for covering left-overs also work.
 
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