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  1. #1
    Join Date
    Sep 2015
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    Australia
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    51

    Default Any point in having a fire detector in a workshop?

    Guys I've been reading a lot online about installing smoke/heat detectors in a workshop.

    Seems the consensus is that regular (e.g. photoelectric) smoke detectors are no good, because the fine dust causes a lot of false alarms. This has been my experience too - my photo electric sits disconnected doing nothing.

    Heat alarms are recommended but many say these will only alert you in the later stages of a fire breaking out, and won't be early enough for you to save the workshop, but might give you the chance to save the attached house.

    Thing is, my workshop is seperate from the house, so I'm not worried about the house catching fire. Is there really no point in having a heat detector in there? We're talking thousands and thousands of dollars worth of machinery not to mention the value of the workshop if it were to catch fire...I'd really like to do something !

    Any thoughts / ideas?

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  3. #2
    Join Date
    Feb 2016
    Location
    Perth WA Australia
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    736

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    Smoke alarms are primarily designed to wake you up in the event of a fire while you sleep. Things like electrical shorts and heaters are the most common culprit of starting a fire.

    From that perspective my opinion fire alarms in a shed are not very useful. Plus given that when i'm not in the shed everything is powered down/unplugged so the likelihood of a short occurring is also exceptionally low.

    So I don't have an fire alarm in my shed, but do have a fire extinguisher in the event that i do notice something igniting other than that insurance will have it covered.

  4. #3
    Join Date
    May 2020
    Location
    little Hampton
    Posts
    127

    Default

    Had never thought about this but is a good point, I'm in the fire safety industry as a consultant and most of what I deal with is more about life safety than asset protection. In the workplace generally most fires start as a result of hot works or people doing dumb things, if you have ready access to an extinguisher hopefully with a bit of first aid fire fighting you can get things under control quickly. Is a bit of a risk assessment really, having ordered it bit of gear recently think I will have around $40k of power tools in the shed by November on top of the many thousands in recycled timber, 3 motorbikes, and a fair amount of expensive BBQ's.....would be a $70k loss just in contents at least which would probably be covered in part by insurance but much of what I have is almost irreplaceable and the rest would take a lot of bother and time to replace. This isn't even considering the whole shed replacement process.

    Smoke detection is primarily for life safety yes but they sometimes in conjunction with automatic sprinklers are often used for asset protection purposes when dealing with either high risk or high value processes...or both with early detection critical in being able to get in early and hopefully limit damage.

    The risk of fire generally outside of residences is actually quite low but this does need to be weighed up against potential losses, I have already decided to install a detector, my shed is around 40 m from the house so would need to wire it back to a detector in the house to make sure someone heard it.

    It is possible to hard wire these systems in such a way that they can be turned on and off, if you are in the shed doing dusty work the system could be turned off and reactivated when doing other things or when unoccupied, would be a bit of maintenance required as well to keep the detector relatively dust free but can live with that.

    Thermal detection is another option but they need to get to temperature to activate by which time it would probably be too late to do anything other than twiddle your thumbs until the fire brigade turns up.

  5. #4
    Join Date
    Dec 2004
    Location
    Rushworth, Victoria
    Posts
    360

    Default

    One good tip I read - after doing hot works or using rags to clean up flammable stuff is to go back to shed 15/20 minutes later to check nothings combusted.
    "World's oldest kid"

  6. #5
    Join Date
    Feb 2006
    Location
    Perth
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    27,407

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    Turning alarms off while making dust is not enough as the dust still gets inside and can affect sensors sos they wont work correctly when turned back in. Usually the alarms build up enough dust sos they stay on but sometimes they wont sound an alarm. Cleaning them out works sometimes but better thing to do is cover them or best of all remove them from the shed. I consider I have reasonable dust extraction in my shed but consumer level smoke detectors last between 3-5 years before going awry. In some way they are not much use to me as I cant hear them but my neighbors do and they have let me know a few times.

    Ive had half a dozen fires in my shed all bar one while I was there. The other happened before o installed an alarm and fortunately it triggering a breaker dropout on a household circuit which caused me to investigate. Fortunately it turn out to be caused by an ants nest in a sawdust choked power point and was more of a slow smoulder than a roaring fire.

  7. #6
    Join Date
    May 2020
    Location
    little Hampton
    Posts
    127

    Default

    Agree with that Bob, is not a perfect solution and maintenance would be required and possible replacement from time to time but is better than nothing especially as it seems you have had a few fires already, I do see detectors in industrial settings from time to time so here must be a way around it. Lot's of factors that will affect performance including what we use our sheds for, ceiling heights, detector location, shed layout, extraction and the like. Wouldn't discount it out of hand and would prefer to look at how the performance issues could be mitigated. I'm not an expert in the specific area of smoke detection but have many colleagues that are, as I am intrigued by this will make a point of touching base with them to get there thoughts on all of this and update next week.

    Cheers,

    Rudy

  8. #7
    Join Date
    Apr 2019
    Location
    NSW
    Age
    36
    Posts
    882

    Default

    Ive just but a tiny smoke detector... well it doesnt detect smoke but sudden increases in temperature. Specifically made for kitchens so the toaster doesnt set it off with a bit of burnt toast.

    Cavius Miniature Thermal Heat Alarm | CAVTH10

  9. #8
    Join Date
    May 2007
    Location
    Sth Gippsland Vic
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    3,525

    Default

    In my old workshop we had two smoke detectors connected into a larger monitored alarm system . They would go off if there was smoke . Or if I was spraying finish in the same room or using something like the inverted router sometimes when it was not connected to dust extraction. The inverted router was right under a detector. They kept working for many years . About 20 easy ?
    Not sure how accurate they were but they seemed fine . We would blow them out every once in a while .
    Today's modern alarm systems which alert straight to your mobile phone and where you don't have to have paid for monitoring may be a good thing to have smoke detectors connected into . They also have video which you can log into and have a look at what is going on . The old workshop were two small rooms though and My new workshop is much wider, longer and with a much higher roof . I'm not sure how well detectors may pick up smoke in there now? I want to get a system set up with smoke detectors and cameras one day. I did buy some Bunnings detectors a while back for the house and they were a wast of $ . Half of them are now gone due to failure. What ever the alarm installer in the old workshop used must have been some older better made type.

    Here's something to make you think about paying attention to preventing a catastrophe.

    A poor guy in the UK posted this on the Wadkin Appreciation facebook page a week or two back .

    Obviously if you don't know about a fire starting in the first few minutes and get to it straight away it'll end up looking like this.

    IMG_2067aa.png IMG_2068a.jpg

    At the moment any time I do something fire related risky I go out and have a look around before going to bed. I don't do risky things in the later hours of a workday if I can help it . like welding. Or spraying sparks everywhere with an angle grinder. Watch out for oil soaked rags finishing related.
    And any steel wool left near sparks or battery powered tools. Like this .Robert Brown on Instagram: "Batteries and steel wool is not a good mix . Amazing to see how easily steel burns ."

    Rob .

  10. #9
    Join Date
    Feb 2006
    Location
    Perth
    Posts
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    Smoke detectors are even more problematic if you do some metal work, especially welding or any hot works, and may to certain extent explain why my smoke alarms fail after 3-5 years. I do have fume extraction for most metal work activities but don't have it for example over my MW lathe or mill. Turning and milling does occasionally generates small amount of smoke especially when lube/coolant is use and I turning a piece of hard steel with TC bits, but it's not usually enough to trigger the alarm. What is possible more important are the use of more lubes etc. I use meths as a lube for cutting/turning/milling/drilling Al and a kero/ATM misting system for milling other metals. The MW lathe and metal cutting BS use water soluble oil. Lube oils are also used much more liberally than on WW machines liberally All this means the air is often loaded with solvent/oils more often than a than most WW sheds. I do use general shed ventilation when I remember - in some cases (like using meths on Al - if I don't do this and work for long enough with it I can become intoxicated.

    FWIW, yesterday I annealed a couple of small piece of tool steel. Ideally this steel requires a slow heat up and holding at a "dark red" temperature for about and hour per inch thickness, and then a slow cool. My gas powered furnace would have done this in a doddle but I sold that a couple of years ago and my replacement electric furnace needs its elements replaced. So I used a wood fire. It's the first time I have had fire in my back yard (inner city suburban block 1 mile from the CBD) and I was bit worried the smoke might upset the neighbors, It was also the first time since I had particle detectors running continuously to monitor dust levels. These detectors are inside the shed and (4 of them) inside the house, about 5m away in both cases, door to shed was open, door to house closed.. The fire only smoked visibly for 10-15 minutes or so when it first started and then when I put more wood on it. The particle detector in the shed initially went over 250 g/m^3 which is about 1/3rd of what I see on some days when the fire authority in the Perth hills do some burning off. after about an house it settled down to about 50 g/m^3. Even with the door closed to the house it still reached 50 g/m^3 in kitchen and 30 g/m^3 in the study at the other end of the house.

    I thought the shed smoke alarm would have a problem so I took it down and put it in a plastic bag. The house has 3 fire alarms (kitchen, hallway and study) but none of those went off.

  11. #10
    Join Date
    Feb 2016
    Location
    Perth WA Australia
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    736

    Default

    Auscab your post just made me realise there is a cheap work around.

    Ive got baby monitors that we purchased many years ago when my kids were younger. The monitors have a high and low temp alarm that could potentially be used as a stop gap instead of thermal alarms, plus they double as surveillance incase you wanted to keep an eye on (or whisper sweet nothings to) your babies in the shed.

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