Is Your Computer a Fire Hazard Waiting to Happen?

whoppers asks: "I'm sure we've all had our share of computer fans die, but what happens if your box is running while you're at work and several fans go out? My in-laws spare TigerPC AMD K62-400's power supply fan just went out about two hours ago, and the thing was blazing hot. A little poke to the blade, and it started up again, but shouldn't these things be made to stop if the fan stops for any reason? I'm starting to wonder if I should start leaving my box off when I'm away for a few hours. Since it's usually wide open, I don't see too much harm, but these cheap boxes that never get opened and cleaned have to be a hazard right? I can't afford a halon system in my office just yet. The only link I found related to this is here and should a few more people read this, here's the cached version. Does anyone have any thoughts or stories related to this?" The fact that this article appears on July 4th, when most Americans will be lighting fireworks is purely coincidental. That doesn't change the fact that the submittor raises a very good point. A general rule of computers is: the older they get, the more dusty they are and dust bunnies and their denser cousins are highly flammable. Unless you can keep such machines clean, it' is probably safer to leave them off.

ASUS

[selderrr]

the new ASUS motherboads have COP : CPU Overheating Protection, which switches off the machine when temp goes baloony.

And they're damd fine MoBo's too...

Re:Simple Solutions.

[rehannan]

Use an air compressor on your computer if you want a fine mist of water sprayed over all your expensive electronics. Air compressors have drain plugs for a reason!

Your much better off just buying cans of "compressed air" (it's actually not air per se).

Re:Can see the headlines now:

[znu]

I believe all Mac models made in the last few years will automatically switch themselves off if they overheat. This dates back to the Blue & White G3, where you could invoke thermal shutdown by running too long with the case door open (which prevents proper airflow over the processor).

Using the wrong computers?

[gerardrj]

Perhaps if this has become a fear for you, then you should visit Apple [apple.com]. All of my mac systems to date run very cool. I've intentionally shut down the fans (usually one, not more than two in a case) and run the computers for hours without any significant heat build up.

The PPC runs much cooler than its x86 cousins. Mac cases also tend to be built with convection cooling in mind with vents on back and sides unlike most solid metal cases sold for use as x86 machines. The inside of my G3 didn't start running at all warm until I installed a VooDoo5/5500 card (that thing pumps out some heat).

I'm not looking to start a war here, but this is simply just one aspect of the Mac that most people seem to like: the cases. Many articles and revires pine over the Mac's enclosures, wishing some generic case vendor would attempt something like that for the modders on the x86 side.

Mac OS does this

[vought]

Mac OS X will terminate on an overheat signal. On the new XServe, the machine can be configured to send an alarm or shut down upon fan failure.

But I guess you get what you pay for, since Macs can be significantly more expensive.

How easy would it be to integrate that sort of thing into all the flavors of Windows or into Linux?

Re: Always open?

[Antity]

Of course, if the reason the case is off is so that you can point a desk fan at the innards, that's a different story.

... the problem being that if something really catches fire (quite common for electrolyt capacitors), the sparks will have great fun flying all over your (wooden?) desk with the latest printouts of your source code all over it.

I also did this for quite a while before I thought about it. Now I guess that this is even more dangerous.

Actually, yes

[CrystalFalcon]

Tom's Hardware Guide showed how the CPUs had reached 300 and 370 degrees C in the infamous thermal tests once the cooling was shot. The ignition temperature for paper is typically in the 175-200 degree range.

Re:ASUS

[Anonymous Coward]

not to mention that all intel chips since the Coppermine Pentium 3 have had auto shutdown on overheat. The new P4s will actually underclock themselves if they overheat, and P3s on overheat will automatically lock hard.

Re:Actually, yes

[CrystalFalcon]

Link [tomshardware.com].

Yes, specced clock and voltage, and then heat sink shot (removed) to see what happened. The overheating ones were AMD procs; Pentiums did not (I say again, DID NOT) overheat anywhere near these temperatures.

I don't remember the ignition temp for your average plastic, but I do remember (from office fire safety training) that paper tended to have the lowest ignition temp of everyday materials, closely followed by wood. My associations to burning plastic are more along the lines of "toxic as hell so get out", I don't remember a specific temperature.

Re:Actually, yes

[Papineau]

Ignition temperature for paper is 451 deg Farenheit, hence the title of the book. For the rest of the world, that's 233 deg Celsius. Still lower than what a bare CPU can reach.

don't run your computer open

[g4dget]

Since [my computer] usually wide open, I don't see too much harm, but these cheap boxes that never get opened and cleaned have to be a hazard right?

Computers are not designed or approved to be run open. It's a stupid thing to do if you are afraid of fire--they get less air circulation, they run hotter, and if they catch fire, the fire can more easily spread. Running your computer open also violates FCC rules because it will cause lots of interference, affecting radio operators, police and fire communications, baby monitors, and medical equipment.

Computers are designed with metal cases for good reasons: they allow the fans to work, they conduct heat, they keep RF inside, and they offer some protection against fire. Don't run your computer open--it's just stupid.

small hazard, yes, and you can make it smaller

[Anonymous Coward]

dust bunnies in the case you probably have under control, but don't forget the psu. that has shock warning stickers on it because it _can_ kill you, so if you're not qualified, take it to someone who is for a quick cleaning once in a while. bring them sushi.

the amount of crud in an older psu can be just incredible. a few AT's i've opened had charred dust.

a few people have mentioned UL safety tests. generally this is correct, but keep in mind some outfits ship cheapened components hoping they won't get caught in an inspection.

some have also mentioned that the pc isn't likely to burn down your house because of some dust smoldering inside the steel box. likely this it true, even if the capacitors explode. make sure this is true for you by not burying your box under papers and pushing it against a curtain behind your desk. just have a look -- if it was on fire right now would it ignite anything alongside? no? then in a worst case senario you'll be woken by your fire alarm and can leave the house okay. some dust on fire isn't going to asphyxiate you.

don't forget the monitor. one of mine tried to catch fire but i caught it and yanked the cord. just got some smoke. probably the UL safety would have saved it anyway, but if those capacitors had burst first... now i shut down when i leave the area.

now guestimate how many offices leave monitors running screensavers all night since 1985 versus how many fires you've heard of. computer fire is a very low risk. take some basic precautions and relax. traffic is what you should be afraid of, and your bathtub, and maybe tetris.

Re:Danger with Old PCs

[zaffir]

For cleaning any bearings, i suggest two things.

First spray down the bearing with fast-drying, plastic safe electric motor cleaner (find it at the R/C car section of your local hobby shop). Make SURE the label says the stuff is plastic safe and dries fast (fast meaning 5 seconds).

Next, put a few drops of bearing - NOT bushing - oil/lube (available at that same hobby shop) on the bearing and spin the fan with your fingers. The fan will spin like new.

Thermal monitering software

[Yottabyte84]

Under both Windows (Motherboard Moniter [livewiredev.com]) and linux (lm_sensors [lm-sensors.nu]) software exisits that can moniter the built in thermal and fan sensors that most modern motherboards have, and can be configured to shut down your computer when it overheats or a fan fails.

Honkey Crap

[tarsi210]

This system administrator woman is full of honkey crap in so many ways. I urge people to leave their machines on for the following reasons:

1. Most modern systems are made to "sleep" when you're not using them. If your monitor is set to power off, your hard drive to spin down, you'll be fine. Power consumption at a low, automatically.
2. Every hard drive that I've seen fail sans one or two have failed when the machine got turned OFF. The next time you turn it on...nothing. Rarely have I seen a harddrive fail while the machine is powered up.
3. The power surge that flows across the motherboard at powerup, not to say anything about the repeated heat-cool-heat-cool that the chips go through as you power on and off each day cannot be good for them.
4. Dust does accumulate, but not THAT fast. I just powered down a 279 day uptime server and the dust was there, time for a cleaning, but nothing significant. (2 fans - 1 PSU and 1 CPU)
5. Security by shutting computers off isn't security, I don't care who you say you are. Educate your users.

Re:Poll

[Technician]

Having dealt with several failed fans in the history of being a service technician, I must say I have never seen a fire related to a fan failure. Most of the time people bring them in because of a smell and before anything shorts out. I replaced the fan and the warranty is void sticker with our shops and send it home. (now supplies are cheap so we just replace the supply except for the hard to get proprotiory junk)
Most smoke issues seen have been:
Ruptured filter capacitors. They have a steam rupture due to the electrolytic. (the end blowes out some times ejecting the roll of tin foil) Boiling water is not hot enough for any flames and the spacer is still wet and won't catch fire.
Shorted power transistors. These may smoke the case of the transistor or take out some flameproof resistors before taking out the main fuse, but again no flames. Shorted disk ceramic or tantilium capitors. These are not made of flamable materials. Last is Metal Oxide Varistors (surge protectors). These tend to smoke the covering, but the part itself is made of non-flamable materials.
In monitors, shorted high voltage supply transformer and the degausing thermistor The transformers really stink with a burning plastic and tar oder, but they are built with self extinguishing materials. The thermistors smoke the plastic covering, but the part itself is not flamable. Again, never had seen a flame continue burning after the fuse or regulated power supply removed the power.
In summary, unless you get enough combustible lint near a severely overheated part, the risk of fire is very low.
The only fire issues I have ever heard about were caused by some defective battery packs for a laptop. There was a massive recall for the batteries. I certanly wouldn't a flaming laptop in my lap. I may want children someday.

Re:Supply may still light a fire!

[arkane1234]

There is more than the power supply that gets hot, and thats the point of this article.

With gigahertz+ machines on the market, a simple cpu fan falling off (hey, it happens...) from being banged around during a lan party or something, or the cpu fan just dieing can lead to a cpu meltdown.

In earlier AMD athlon testing, this can and most likely *will* cause fire if left alone. (unattended file transfers, anyone?)

But, I do know that the P4 is great about that with it's thermal protection. You can drop the heatsink off and it'll clock itself down until it's not overheated anymore. I'd imagine it would do the same if all the fans went out in the machine.. of course it'd probably be so slow it's unusable, but you know.

Yes.. I do know this happens, because I started my system (P4 1.8ghz) without the heatsink on the first time. Was slow as molasses... popped my dragon-P478 on and cranked the fan up to medium, POW... speeded right back up.

*DON'T* Use WD-40 on small moving parts (ie. fans)

[BigBlockMopar]

Functionally, it works as a lubricant fairly nicely. Also as a cleaner. It also kills ants, and, with a lighter held in front of it, is a fun party tool. It may not be the best at any of these, but it functions pretty well as a general purpose tool - I keep a small can in my toolbox, and usually have a large one around. For parties.

I agree with everything you've said except for *one* thing.

Don't use WD-40 as a lubricant. Use it as a penetrating oil, to free stuck and seized moving parts. But once they're unstuck, clean them thoroughly with carb cleaner or something similar, and then use a proper oil or grease to lubricate them.

Speaking from experience, WD-40 turns sticky with time. Small machines (ie. computer fans) will seize.

If you *have* to lubricate a disassembled computer fan, use ONE drop of the lightest machine oil you can find - the smallest SAE viscosity number.

However, dust in the air passing through the fan will magically be attracted to the bearings and trapped in the oil, where it will eventually seize the fan again.

Good computer fans have graphite-impregnated sleeve bearings. When the bearing ceases to be self-lubricating, the bearing is worn out and it's time to replace the fan.

Cheap computer fans (and those sold to people who don't know any better) use tiny little ball bearing assemblies. With outside bearing diameters of less than 1/8" in some cases, the balls are absolutely tiny, especially relative to any dust which might become trapped in them. The "ball bearing" fans are especially prone to failure, and should also be avoided, unless you're buying expensive ball-bearing fans for use in your clean room.

Replace the fans. If you have to take them apart to clean/lube them, they're finished, and will fail again soon.

www.papstplc.com [papstplc.com]

and, manufacturer of the legendary Muffin Fan used everywhere from Cray computers to the Space Shuttle,

www.comairrotron.com [comairrotron.com]

I don't believe in repairing cooling fans, and I don't believe in the cheap crap which washes ashore from Taiwan and infiltrates our computer cases.

Buy good fans. They'll outlast your computers, and you'll never need to do more than vacuum them.