My apartment's bath fan caught on fire - Page 1
Forum section: electronics / general

author: pigrew
author_rank: Frequent Contributor
timestamp: June 10, 2020, 08:29:32 pm
content: This morning was somewhat eventful. Our bath fan caught on fire. We're all safe and there was minimal damage.TLDR conclusions:Loud shaded pole motors must be promptly replaced.Don't spray oil all over a dusty motor.Bathroom fans should be cleaned yearly.Iowians do not fear fire.The apartment management does NOT have a good "safety culture".Bath fan plastic is not self-extinguishing.Putting out a fire quickly is a good idea.Call fire services as quickly as is practicableIf safe to do so, close doors and shut off electricity & gas as you leave a building on fire.Bath fans should have a thermal overload, but do notI'm staying in an American apartment (in Iowa, built in 1979, 8 two-bedroom units), and our bathroom extractor fan caught on fire.My roommate noticed the fan wasn't running when the switch was turned on, and a minute later noticed that it was glowing (so he told me that it was glowing...).I verified the fan switch was OFF, and then removed the cover of the bath fan (giving it more combustion air), and saw that, yes, there were flames. It looked like a candle flame, just much much bigger. Removing the cover could have been a bad idea since it gave it more air, but on the other hand it let us assess the situation.Next, I called emergency services and ensured that my flatmates knew there was a fire. The cell phone connected to the county services, I gave them my address, and they had to transfer me to the city (30 second delay). The city dispatch had a script to run through. Once I said fire, she asked for my address, told me to pull a fire alarm (the building doesn't have a central alarm system, so I couldn't), asked how many floors there were, and told me to get out of the building. She said NOT to use a fire extinguisher. I ignored her advice. Maintenance had removed the extinguisher from our unit a few months ago (saying that too many kids used them, making messes, and that they are no longer required by the fire code), so I went to the hallway to grab the communal one. I held my breath and used it. The ABC power got everywhere and the fire was immediately extinguished. Finally, I turned off the six electrical breakers in the breaker box (NEC allows there to be up to six independent breakers without a main) closed the bathroom door (to reduce drafts). I knocked on the door of the apartment directly above us, but nobody answered. If there was still a known active fire, I maybe would have kicked down the door to look for people (though maybe that would get me shot???). I then left the building.The fire brigade arrived four minutes later. They had three engines (maybe one was ladder truck?), and command in a pickup. I said hi to the firelady and explained the situation. They came inside and tore down part of the ceiling and opened up the exhaust port to check for embers. They also used a FLIR camera. One had a SARS-Cov-2 surgical mask on, and the other didn't have a mask. They also brought a big fire extinguisher with them (CO2? Halon?), but didn't use it.Once everything was clear, they packed up. They noted down my name, birthday, and phone number for notoriety. The apartment management was called by the responding people, but we called, too.The building was never evacuated. Other tenants seemed seemed unconcerned when I said our bathroom caught on fire.The maintenance people arrived half an hour later, and replaced the motor and fan blades. They also hired a fire damage repair company to repair the ceiling and sweep up the ABC powder (I still have the taste in my mouth). Since the fan had a metal grill cover, it's likely it would have eventually self-extinguished, but it was still a dangerous situation.The fire department said that maintenance must replace the spent fire extinguisher by 5PM today, or else there would be a fine. The department has a policy of fining people $500 for needless calls, but they saw there was a real fire, so we didn't incur any fees related to their visit.I believe the fire's proximate cause was bearing failure in the shaded-pole motor, causing overheating and ignition of oils. The motor (and also its replacement) do not have a thermal overload, as it relies on the coil resistance to limit the stall-current. Last month, we reported to maintenance that the motor was loud. It was visibly dirty. Maintenance saturated the motor with oil, and did not clean the dust. Once the bearings finally seized, the oil-soaked lint caught fire, igniting the plastic in the motor housing and fan blades. This event should prompt them to periodically inspect all bath fans and replace them as needed, but I highly doubt that they will.PS: As an ancillary note, maintenance once put a bunch of Americium smoke detectors in the dumpster, and they got wet in the rain. They were sounding for about 18 hours, overnight. Maintenance refused to come out and disable them, so I could hear smoke alarms going off ALL night. They were adamant that it was not a safety issue. I constantly wanted to evacuate the building, feeling that another apartment was on fire. I also didn't want to crawl into the dumpster as this was the local maximum of the virus plague. I did call the police with a noise complaint, but they were not servicing noise complaints because of the virus... Nobody else in the apartment even noticed the alarms. Another issue was when we reported our unit's fire extinguisher hadn't been inspected in ten years. Their response was to remove it, but leave behind the sign saying that there was a fire extinguisher in the closet.

author: cdev
author_rank: Super Contributor
timestamp: June 10, 2020, 09:57:18 pm
content: Glad you are okay! This is a good reminder for me to clean out our bathroom fan and dryer vents.

author: tom66
author_rank: Super Contributor
timestamp: June 10, 2020, 10:02:25 pm
content: Glad you are OK. Fires are scary. I am glad we only have a passive vent in the bathroom.In the UK it has been suggested that the severity of the Grenfell Tower fire (which killed 72 and left 600 homeless) was significantly increased by the recent installation of uPVC window frames and plastic kitchen and bathroom extractor fans. Prior to the renovation, these were aluminium framed windows, and there were no extractor fans. As the fire spread up the building, the plastic frames and extractors failed, which allowed the fire to more quickly spread into living spaces with the plastic acting as a fuel to spread the fire within the apartment. While the cladding was likely responsible for the spread of the fire across the face of the building, the retrofit used large quantities of expanding foam and flammable insulation around parts, and had large void cavities where windows had been retrofitted into the new cladding system.

author: Larryc001
author_rank: Regular Contributor
timestamp: June 10, 2020, 11:25:50 pm
content: This is not the first time I have heard of this happening and it is very scary. I am glad you are ok. A few years ago Calgary Harley Davidson burned to the ground during the night. The cause was traced to the bathroom fan catching fire and destroying the building along with millions of dollars in inventory, tools, and equipment. Stay safe.

author: Homer J Simpson
author_rank: Super Contributor
timestamp: June 10, 2020, 11:28:51 pm
content: Yes,I take down and blow out with compressed air once a year.Also, I never leave on if not at home.-K

author: Bud
author_rank: Super Contributor
timestamp: June 11, 2020, 12:01:56 am
content: I installed a timer on mine. Very handy.

author: pigrew
author_rank: Frequent Contributor
timestamp: June 11, 2020, 02:39:22 am
content: Quote from: Bud on June 11, 2020, 12:01:56 amYes, that's handy. Here, our fire ignited a few minutes (four?) after the fan was energized, so a timer would not have prevented our particular fire. Building maintenance spraying the motor with oil was definitely a causal factor.In my house (not this apartment), I have an expensive fan that detects humidity levels and turn itself off if it's dry enough, though it also has a forced-full-speed mode (Delta VFB25ACH). It uses a BLDC motor, so I'm guessing it would have stall-detection and fail safe, so less likely to have the motor overheat. Then again, it has more moisture sensitive electronics (capacitors, transformers, etc), which could themselves be a fire hazard.

author: james_s
author_rank: Super Contributor
timestamp: June 11, 2020, 02:50:14 am
content: I've seen this happen myself too. When I was in highschool I worked part time as maintenance at the apartment complex my friend's parents managed. We had a fire in a unit while the occupants were on vacation. It was the laundry room fan that caught fire, then the plastic grill caught fire and drips of burning plastic dropped onto the washing machine. These were GE washers that had a fiberboard back panel and that caught on fire, melting the wiring so the washer started running then it burned through the water supply hose which started spraying water everywhere largely putting out the fire. Somebody saw smoke so we entered the apartment to find it was flooded, the washer was running and there was smoke pouring out of the laundry room. We shut off the power and water and then the fire department came and went we moved most of the belongings up off the wet floor and into another unit. It was a big mess that could have been a lot worse, I was never sure how it happened since I thought those motors had thermal fuses in them but apparently they're not infallible.

author: coppercone2
author_rank: Super Contributor
timestamp: June 11, 2020, 02:54:24 am
content: this is a good reason to investigate the kitchen stove extractor vent. it sounds like it could get in the same condition as your bathroom without evil maintenance menDoes anyone feel like they noticed increased maintenance problems on appliances since the coronavirus, since you are at home using them more? I almost feel like its a international stress test for all the stuff that's been slowly getting more and more scammed. For some reason I imagine like execs that have expensive stuff for show (in the sense that value is never extracted from use) that normally go out all the time are starting to notice stuff is not built for duty cycles of home bodies?

author: amyk
author_rank: Super Contributor
timestamp: June 11, 2020, 03:07:21 am
content: These motors should be impedance-protected meaning they will get warm, but not hot enough to cause damage, indefinitely, if stalled. Stall current is not much higher than the running current.Whoever decided to spray the whole thing with oil is just being an idiot and the actual cause of the fire --- I suspect the cause was actually arcing of loose connections which ignited the oil.

author: helius
author_rank: Super Contributor
timestamp: June 11, 2020, 03:20:41 am
content: Quote from: pigrew on June 10, 2020, 08:29:32 pmIf you do not expect that someone would shed a tear over your painful death, it is not wise to entrust your life to them.This is a lesson that people are remarkably resistant to learning: on the topic of recent events, a persistent narrative spread thatprotecting yourself from COVID-19 makes you an "asshole", and the only permitted action is to protect others.This while venturing out in any city today, you see people on the street without masks, or with masks hanging down around their chins. So enamored are they of the grand idea,Un pour tous et tous pour un, so must embrace a willful ignorance of reality.

author: bill_c
author_rank: Regular Contributor
timestamp: June 11, 2020, 04:33:10 am
content: Make sure you have smoke detectors properly installed and that the batteries are changed as needed. You can't smell smoke while you sleep. Without a functioning smoke detector, you will not wake up as the place fills with smoke. Without a functioning smoke detector, you will not wake up as the place fills with smoke. Yes, it is worth repeating as many times as needed.I mean everyone, every house, not just pigrew.

author: james_s
author_rank: Super Contributor
timestamp: June 12, 2020, 03:47:09 am
content: Quote from: bill_c on June 11, 2020, 04:33:10 amIndeed, I actually knew a guy who died when he left something on the stove and fell asleep, set his apartment on fire and resulted in his death and everyone who lived in the building being displaced. He had a vaping habit and had disabled the smoke detector in his apartment, had he not done that he'd still be alive. He wasn't very old either, 22 I think, one of those sorts who was his own worst enemy.I have a smoke detector in nearly every room of my house.

author: Someone
author_rank: Super Contributor
timestamp: June 12, 2020, 04:35:49 am
content: Quote from: bill_c on June 11, 2020, 04:33:10 amThankfully they are legally required in many residence types now.

author: Lord of nothing
author_rank: Super Contributor
timestamp: June 12, 2020, 11:20:31 am
content: Well it look like a typical US Cardboard House.With a Brickwall and Concrete Ceiling nothing special would happen:But why make it rock solid when the Russian Style look good...

author: Electro Fan
author_rank: Super Contributor
timestamp: June 12, 2020, 03:19:22 pm
content: Quote from: helius on June 11, 2020, 03:20:41 amBig +1Some empathy could help build a path to trust.

author: aqarwaen
author_rank: Regular Contributor
timestamp: June 12, 2020, 04:58:26 pm
content: do you stil got that fan?any clue what may have failed in there?maybe you can teardown it and post few pictures?

author: maginnovision
author_rank: Super Contributor
timestamp: June 12, 2020, 05:10:39 pm
content: Probably bearings or just too dirty to start up. Not a whole lot can go wrong with those.

author: pigrew
author_rank: Frequent Contributor
timestamp: June 12, 2020, 06:29:05 pm
content: Quote from: aqarwaen on June 12, 2020, 04:58:26 pmI would love to, but the apartment maintenance took it away. I looked for it in the dumpster, but didn't see it. I only got a brief glimpse, but it was mostly the fan blades that had melted.The design is very similar to this YouTube video:.The video even shows a lot of rust and lint, just like mine had.Quote from: maginnovision on June 12, 2020, 05:10:39 pmYes, the bearings were most certainly failed (or gummed up). Before catching fire, the fan was not turning. I didn't think that a shaded-pole motor would normally have any spark-source since there are no brushes. Perhaps metal-interference in the bearings created sparks, or arcing due to damaged magnet wire insulation?Quote from: bill_c on June 11, 2020, 04:33:10 amI agree, and have one smoke detector per floor in my house. This apartment has three detectors, one in each bedroom and one in the hall. All of our's are independent stations (no interconnection within the building). I've contemplated replacing mine with an interconnected system, but I'm not sure if it's worth the effort of running more 14/3 Romex through the walls (and my circuit breaker box is full after adding a SPD).One of our neighbor's units upstairs has a low battery (I hear a the periodic chirp from the hallway)... nobody seems to care but me.I also highly suggest having CO detectors on each floor if there are any gas-fueled appliances. I use low-sensitivity >10ppm models, though I wish that inexpensive more sensitive models are available. This building has one upstairs near the central boiler (no other combustion appliances). Iowa requires them, by law, for all residences (or maybe just ones with combustion appliances?).As an update, we still have a square foot-size hole in our bathroom ceiling, exposing the upstairs subfloor. I doubt apartment management will fix it before we move out in 7 weeks. Yes, it's a small fire concern (needs fireproofing, to slow fires), but I don't think it needs immediate action. Our floor's fire extinguisher was replaced at 8 PM the day of the fire (I later got conflicting opinions on if they had 24 hours to replace it, or if it was due at 5PM). The management's insurance hired a flood/fire cleaning company to clean the bathroom. After that, it was cleaner than it had been when we moved in. There's still a latent smell of ABC extinguisher powder. Mixing the powder with laundry soap released an ammonia smell. I'm guessing that chlorine gas could be released if bleach solution were used. Reading more, it seems that baking soda slurry and isopropanol are the appropriate cleaning agents. Monoammonium phosphate is also corrosive to metals.

author: Larryc001
author_rank: Regular Contributor
timestamp: June 14, 2020, 09:03:30 pm
content: Our new house has smoke and CO detectors in every area. The run on both AC and 9 volt batteries and are linked together so if one is triggered it triggers all the others. Quite exciting when the smoke from the barbecue blew in the other night and set them all off. Oh yea they all also have a voice warning. Certainly no way to sleep through that. I don’t know if this is code, I suspect it is.

author: NiHaoMike
author_rank: Super Contributor
timestamp: June 14, 2020, 09:47:43 pm
content: Quote from: pigrew on June 12, 2020, 06:29:05 pmThere are a few wireless interconnected alarm systems like Nest, as well as low voltage interconnected alarm systems.Quote from: james_s on June 12, 2020, 03:47:09 amTwo words: Darwin Award.

author: VK3DRB
author_rank: Super Contributor
timestamp: June 16, 2020, 12:23:18 am
content: A mate's bathroom fan caught on fire. $20,000 worth of damage to his home. The cause was a fan from China which had no safety approvals, not even the RCM or CE marks. It is very likely it had no thermal fuse in its windings and the plastic has no fire retardant in it.Unfortunately a lot of non-compliant product has found its way into Australia. The worst was mains flex cable where the insulation goes brittle and cracks when exposed to high temperatures like in a ceiling. The stuff was sold all over Australia through major hardware stores. The importer of this illegal cable was hunted down. The media called her the "cable girl".https://www.news.com.au/finance/money/cable-girl-scandal-could-cost-80-million/news-story/6f8af4d1590fd580b234c98f1b1ada5c

author: tkamiya
author_rank: Super Contributor
timestamp: June 21, 2020, 02:07:57 am
content: I've been finding many of electrical fixtures available from online sources are not UL or ETL certified. When it comes to wires, I insist on a particular maker and buy it locally. Fixtures, I make sure it is UL or ETL certified.UN-certified products are EVERYWHERE in US. It is really a horrible situation. Kind of reminds me of aluminum wire fiasco, although nature of it was a bit different, damage was just as extensive.

author: VK3DRB
author_rank: Super Contributor
timestamp: June 21, 2020, 04:23:51 am
content: Quote from: tkamiya on June 21, 2020, 02:07:57 amThat is because the US, Australian and other governments are pretty much inept enforcing safety compliance with imports. That is why so much dangerous stuff comes in via eBay.After an innocent young woman in Sydney was electrocuted by a non-compliant iPAD battery charger she had just purchased from a Chinese cheapo import shop in New South Wales, the chief of the NSW Office of Fair Trading implied to the media that non-compliant chargers were a new issue and they would look into it. The truth was that non-compliant chargers were commonplace in these types of shops and the government simply failed to so its job. They and the importer should have been made fully accountable for the death of this young woman. It was not the purchaser's fault.The police fine people here $1652 for or not social distancing as required. We should be doing the same for every unsafe non-compliant import, starting with eBay imports.

author: Lord of nothing
author_rank: Super Contributor
timestamp: June 21, 2020, 09:58:37 am
content: Sry here in europe a lot of Company buy in China without testing anything.The resell there crap without think about risk (get sued and loose maybe all there private value).

author: Stray Electron
author_rank: Super Contributor
timestamp: June 21, 2020, 02:50:30 pm
content: Quote from: tom66 on June 10, 2020, 10:02:25 pmI built a steel outbuilding a few years ago and I thought about using that expanding foam to help seal the joints but I decided to test it first, so I took a cured sample of it and set it on fire to see what it burned like. That stuff burns GOOD! I would NEVER use that in a building again. I used the standard fiberglass mats instead and don't even use the foam to plug holes. I just stuff in pieces of fiberglass mats.

author: tom66
author_rank: Super Contributor
timestamp: June 21, 2020, 03:38:44 pm
content: If I recall correctly expanding foam is usually "expanded" using butane inside the cylinder. I don't know if that remains after the foam is set, but if it does, it almost certainly helps accelerate the process!

author: tkamiya
author_rank: Super Contributor
timestamp: June 21, 2020, 03:48:21 pm
content: As far as I know, there is no law in US prohibiting importing, selling, buying or using non certified electrical equipment. UL certification is voluntary. It shouldn't be!

author: tom66
author_rank: Super Contributor
timestamp: June 21, 2020, 03:49:04 pm
content: Would importers not bump up against FCC regulations, for instance?

author: tkamiya
author_rank: Super Contributor
timestamp: June 21, 2020, 03:56:08 pm
content: I don't think so, in this case.I read the FCC regs and they classify incidental and intentional radiators. Fan will be incidental but there are exceptions. At least I've never seen a fan with FCC certifications. Besides.... who's checking? I insist on UL but no one checks and huge amount is coming through various methods and channels. It's a mess.

author: amyk
author_rank: Super Contributor
timestamp: June 21, 2020, 11:21:41 pm
content: Quote from: tom66 on June 21, 2020, 03:38:44 pmClosed-cell foam will contain trapped blowing agent (which may slowly seep out over time), whereas it will dissipate quickly in open-cell foam.I'm not sure that they'd use something as flammable as a hydrocabon; they are usually something nonflammable like a HFC (used to be a CFC --- and in China, maybe they are still using CFCs). Foam is really a form of plastic but what makes it so flammable is its huge surface area.

author: Mr. Scram
author_rank: Super Contributor
timestamp: June 21, 2020, 11:44:18 pm
content: Quote from: bill_c on June 11, 2020, 04:33:10 amI know people who got lucky and were woken up by the sound of the raging fire breaking glass. That's cutting it close. But yeah, smoke detectors are cheap and improve your chances hugely. Even if you're awake it may buy you those 30 seconds between a bad day and the last day of your life, or a loved one's. People have no idea how quickly a fire can escalate.

author: Jeroen3
author_rank: Super Contributor
timestamp: June 22, 2020, 10:08:33 am
content: PU foam should contain flame retardants like TCPP. But yes, they still use isobutane, dimethylether and propane as propellant.I mounted a few of theseAFFFfoam units around the house. Fire is really scary.