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Comment by rdl | Hacker News Reader

IR/thermal imaging cameras are SO USEFUL. I had a fire (bathroom fan caught fire due to being 45y old, knocked it down and extinguished it myself, but was worried about extension in the ceiling/duct).

Oakland FD came out and used their IR camera to check the heat from the ceilings nearby. Hilariously they found a hot water pipe (running between bathroom and kitchen) and almost axed the ceiling open (turning $1500 in damage into $3k+), but their captain was smart and figured it out from another angle.

Really tempted to hack an EOS 5Dm3 into an IR camera next. Not so much for fires as night vision, but it would be useful for fires too. I'm not sure how useful an IR camera is at detecting heat, since things which aren't yet on fire are not quite so infrared, though.

I usually use a Fluke IR temp meter when cooking and to find hot wires/etc. in the datacenter, though.

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They are useful but they do have limitations. I'm not sure it would have necessarily detected the faulty battery in this case. Last year, there was a fire at my house and the FD searched for the source for three hours. With thermal imaging and everything. It was inside the walls, no open flame, just a lot of smoke and no clear readings on the imager. That was pretty frightening. (However when they finally did find it, they put it out in a couple of minutes.)

I'm glad it motivated me to get ABC Dry and Halon 1211 extinguishers for both rooms and the car, at least.

In a "real" datacenter, you should have smoke sensors which would map where heat/smoke is coming from (since you have controlled airflow, it should be obvious which rack or small group of racks was the source -- it doesn't just exhaust into the whole room). But it's pretty clear this wasn't a "real" datacenter by their lack of protocols for handling fire, it was some office server thing.

I'm just saying these things can quickly get more complicated than expected. I too had extinguishers handy at the time but of course I didn't know what to use them on (and neither did the FD for three hours). These electrical fires can be tricky to debug, especially when different kinds of barriers come into play.

> But it's pretty clear this wasn't a "real" datacenter by their lack of protocols for handling fire, it was some office server thing.

Probably. What's the right protocol though? In this case, it was apparently clear that something minor was amiss, nothing that would justify shutting down the whole thing. In any case, flooding the room with inert gas would probably not have made much of a difference, as it looks like the battery was never actually burning.

House construction is insane, anyway -- they're full of random stuff, and there are plenty of non-accessible void spaces. Datacenters are at least generally nice and open, so finding a weird residential hidden fire should be a lot easier. (which is why datacenters get permission to run their wiring the way they do, etc., because they have so much other safety)

The right thing to do in a real datacenter it to check which of your ~hundreds of laser VESDA sensors first tripped, and investigate in that area :) Presumably you have floor air supply, ceiling air return, so the first thing to trip should be a ceiling sensor near your fire. If no floor sensors trip, I wouldn't be super afraid to go in there, and if it's only a small number of them it's not a big fire.

You don't want the dry pipe to go off for sure, and you don't want the FM-200 either, but the consoles should be reporting the smoke alarm to you way before a human would smell it "filling the whole room", and they don't generally discharge either for very small events (at least everywhere I've seen).

In an office (some open plan, some cubicles, some conference rooms and offices, etc.), with a few racks of equipment, and maybe some lab space, it's a lot more similar to the scary hidden residential fire problem. :( Your risks in trying to uncover the problem are actually higher than in the datacenter because then you don't have the amazing gas system and a dry pipe backup to save you if it turns into a big fire while you're there, and it's not as designed for easy egress, and probably doesn't even have real EPO. I wonder if there's a firefighter on HN who would know the real answer to this case.

FM200 systems do go off for small events at times. I managed a team of datacenter facility specialists up until last year, and we'd seen issues like: FM200 dumps because underfloor smoke detectors notice smoke from a CRAC condensate pump (pretty low risk) smoking its winding, FM200 dumps when a quick refrigerant discharge (technician error) looks like smoke to the detector, and false positives at smoke heads due to a dirty area under the raised floor, combined with air flow irregularities.

I definitely agree that I'd be more concerned about a house fire, but the rule that we enforced to our people and the vendors, as well as the vendors working for us (not to mention the guidance that we received from our customers) was that nothing in that datacenter is worth potentially losing anyone's life. That having been said, I have Toucan Sam'd in a datacenter to try and find the source of an odd odor before, but never alone, and only to find out what to secure power to. I wouldn't sit there and try to fight it with a fire extinguisher.

The only "accidental discharges" I've seen were related to construction dust in an underfloor. And yes, suck :(

In general the purpose of a handheld extinguisher is to fight tiny fires as well as to help you escape a bigger fire. The thing I'd be most afraid of would be someone walking around trying to find a small fire, only to discover a big fire, have egress blocked, and need to figure out a solution. Or, coming across an actual person who is on fire or otherwise in danger (even if you'd expect virtually no personal risk for property, I think most people would accept substantial personal risk to save a person, particularly a coworker).

I have had a halon dump when the aircon went out and when it restarted the dust that burnt off the elements caused a dump.

The wavelengths used by heat detection equipment are way longer than you'll pick up with a DSLR, even after a conversion to remove its IR-blocking filter.

Yes, Silicon sensors are not photosensitive past ~900nm. The IR filter is only there to block "near infrared" 700-900nm which is not human visible but silicon sensitive.

How sad. I guess I'll be buying one of the $200 IR-Blue.

> I usually use a Fluke IR temp meter when cooking...

Please elaborate.

I got one of these (Fluke 62, http://www.amazon.com/Fluke-62-Mini-Infrared-Thermometer/dp/...) for $35 or so on sale.

You can get the same guts for $15 (http://www.amazon.com/Accuracy-Non-Contact-Infared-Temperatu...)

It tells you the surface temperature of whatever you point it at, and has a convenient laser for aiming. When cooking, I use it to see if a pain is hot enough yet (e.g. to sear meat), rather than relying on the "smoke point of various oils" test. You can also use it to see how close water is to a boil, although I'm not sure if it is measuring surface temperature, some slight penetration into the water, or the pan bottom (although, arguably, these should be fairly close in water).

It's also useful in something like a fusebox to find hot/overloaded circuits. It's essentially a 1x1 pixel themal imager, while a 100x100 thermal imager costs much more.

You still want a probe thermometer (for measuring meat internal temperature) such as http://amzn.com/B0000CF5MT, and if you have kids/sick people/etc., probably the internal-temperature kind (the ear/IR kind are the least gross).

I have a couple of the Amazon cheapies that I use for checking temperatures when brewing -- it's totally awesome to check the temperature of heating mash water from across the room.

The laser also came in pretty handy for entertaining the most recent foster puppy.

Thank you very much. I have a cheap non-contact thermometer, but I never thought of using it in the kitchen. I will try it out.

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