Smoke / Fire Detectors

[Jim Bennett]

What is typically done to provide fire detection in wood workshops?

For my new shop, the builder put in a standard hard wired smoke detector in order to pass city building inspections. I'm assuming that one day, when I'm generating more sawdust than is healthy, that detector is going to go off and will end up pulled off the ceiling.

If my assumption that fine sawdust will set off the alarm is correct, what would be the right technology to use for early warning of fire? Rate of heat rise detectors?

[Thomas L. Miller]

Jim,
I have both a smoke and heat sensors in my shop. They are connected to the main monitored system for my home. Over the past year that I've occupied the shop, I haven't had any alarms generated by dust (smoke or heat either for that matter :). I've built a large set of cabinets/shelves for my wife's quilting room and used a lot of "dusty" MDF and baltic birch plywood in the process. I do have a dust collector, but it doesn't catch everything. The alarm system was tested when it was installed, so I know it is functioning. It would likely take a lot (and a probably unhealthy amount) of dust to set the thing off. I'm certainly no expert, but that's been my experience.

[Alan Trout]

The problem with putting smoke detectors in a shop is accumulation of dust. While they will not go off from false signals they really will not work either because of accumulation of dust on the sensor. That is the reason in new construction they have dust covers that go over the units until construction is complete. In reality heat detectors may not have the dust problems but unless they are right over the source of ignition they do not typically go off until there is a good fire going. That is the reason that smoke detectors are required by code and not heat detectors.

Just for a overview of what residential codes are on smoke detectors. They should be in all bedrooms and the hall adjacent to those bedrooms. Also code dictates in a residential setting that the smoke detectors will all be hard wired and interconnected with a battery backup. If the house is multi-level and there is no bedroom on one of the floors there will be at least one smoke detector on that floor. The only reason that your shop should have to have one is if it was the only room on that particular floor of the house or that room could be considered a bedroom.

So to sum it up smoke detectors may not work in a shop with a heavy dust environment.

Good Luck

Alan

[David G Baker]

My combination CO2/smoke detector frequently goes off when I use a dull blade that causes some burn marks on my wood. I tolerate it quite well due to a hearing problem in the high frequency range. I need to find one with a lower frequency alarm that I can hear better.

[Jim Bennett]

Thanks for the respones. It sounds like I shouldn't worry about the smoke detector false alarming - just deal with it if it does. It also sounds like I shouldn't count on it really protecting me either.

My shop has A/C and a full bath, so the City inspectors have trouble not considering it living space. The duct work I put under the floor for dust collection certainly had them confused -- I ended up having to get a special "ventilation" permit and getting all of the ductwork inspected (before and after cover up). I don't think they had ever seen anything like my Oneida system.

Thanks again.

[Bill LaPointe]

Have had both a smoke and fire detector in my shop for 12 years. I regularly set of the smoke alarm heating metal or gas welding. Lawn mower exhaust set it off last week while I was putting air in tires with door open at other end of the shop with the motor running. You can say that I regularly test it.;)

[Tom Hargrove]

There are different kinds of detectors, or at least used to be. The less sophisiticated type is set off when any kind of smoke or haze passes over its sensor. An accumulation of dust on the sensor can make it useless. This type may not be code in some communities.

The better type senses the "by-products of combustion," even it they are colorless to the human eye. I was told this type of detector is generally not affected by an accumulation of dust, but I admit I am not an expert in this area. I'm sure detectors are available for dusty conditions.

You can check the website for you detector manufacturer to find out details. Or, you could speak to a local fire inspector to see what they think. If you are concerned about your local inspector putting you on a watch list, visit one of the neighboring departments when they have an open house.

[Lee Schierer]

I've hadhttp://sawmillcreek.org/images/editor/menupop.gif a smoke detector in my shop for over 20 years. It has never gone off due to sawdust. It will go off if I use my branding iron even once (I use it on every project I make)or if I happen to produce a burn mark on a rip cut (doesn't happen often).

Personally I wouldn't worry much about sawdust entering the detector mounted on the ceiling. Dust settles down not up. Still a once a year blow off from canned air or dry shop air probably wouldn't do it any harm.