Pop quiz: You've got a roomful of electrical equipment. How do you put out a fire? A reminder to take care when fiddling with the top shelf in today's edition of Who, Me? Especially when "good" has taken a backseat to "cheap". Our tale takes us back to the closing decade of the last century and comes from "Joe", a senior techie at a major US East Coast satellite uplink/downlink hub. "This included a …
Except he forgot to require that the server room into which it was to be deployed be sealed against the stuff escaping into the rest of the building. One fire alarm later the halon deployed and the building had to be evacuated.
His punishment for the screwup? He got promoted.
It was all the rest of us could do not to strangle the fekkin' bastadge.
Our budget went to shite for six months while we had to run everything from the DR facility so the primary could be retrofitted with the proper seals to prevent another attempted mass slaughter of the building occupants.
Nepotism, it's the only reason some people are still alive instead of having been Darwined off the planet.
I'm puzzled, why would Halon, an inert gas, need to be sealed off from the rest of the building?
If there is something burning in a building, _everybody_ should get the fsck out of the building immediatly, having seals between hoomans and burning toxic chemicals won't do diddly.
Halon doesn't kill you, the products of burning things kill you, especially all the PFTE and PVC byproducts as they burn. Halon at an effective dispersion is at 10% of the air at most.
Halon works by disrupting the actual chemical reaction of burning, it doesn't "displace all the oxygen" or "alter the oxygen to not be breathable" as so many common myths have it.
It is an Ozone depleting gas, so that is why FM200 was developed. Same things apply though.
"I'm puzzled, why would Halon, an inert gas, need to be sealed off from the rest of the building?"
The 'Halon' (nowadays it's never Halon in a new installation, it's something like FM200, which works under similar principles, so everyone just calls it Halon) needs to be delivered to the problem quickly enough and in high enough concentrations to be effective. If the server room is not relatively sealed off or if someone partitions the room and changes the airflow patterns after the suppression system is designed, you risk not getting high enough concentrations to suppress the fire.
You are very correct about the dangers of the burning byproducts. For what it's worth, according to the fire suppression contractor who did our FM-200 installation at $job[-4], the FM-200 also produces byproducts that aren't particularly healthy for you, but "they're a lot less toxic than the shit that would be burning otherwise". He told us that if we were in the room and the FM-200 dumped, we would survive just fine, but if stuff was on fire, getting away from the fire is a good idea.
Our system had an ultra-sensitive smoke detector, plus a conventional fire alarm wired to the building's system. The ultra-sensitive would warn of a smoke byproduct well before it would dump the agent (there was a network of sniffer tubes in the ceiling, multiple zones had to trigger at a high level to dump). The sniffer warned us of a failed power supply in a server it was so good (something in one supply let out the magic smoke). If the FM-200 failed to suppress the fire, we had conventional sprinklers as a backup (they may have been converted to pre-action, sprinklers, I don't recall).
"If there is something burning in a building, _everybody_ should get the fsck out of the building immediatly,"
^This. Call the fire department on your way out or from the parking lot. Fire grows exponentially, every second you delay in calling the fire department makes their job much harder and more dangerous. Also, if everyone is out of the building and *confirmed* to be out, that means the firefighters need to spend less time looking for victims in the fire building.
It will depend on the relative volumes of the rooms involved.
"It is considered good practice to avoid all unnecessary exposure to Halon 1301, and to limit exposures to concentrations of 7 percent and below to 15 minutes. Exposure to Halon 1301 in the 5 to 7 percent range produces little, if any, noticeable effect. At levels between 7 and 10 percent, mild central nervous system effects such as dizziness and tingling in the extremities have been reported In practice, the operators of many Halon 1301 total flooding systems evacuate the space on impending agent discharge."
I was a passenger on a Ryanair flight from Stansted to Valencia when the halon (or whatever the equivalent is these days) system discharged into the cockpit. Not fun when suddenly the automated announcement says "DESCEND! EMERGENCY!" three times and then the plane starts to shake like crazy. The shaking I later realised was full deployment of the air-brakes. The pilots (and rest of us) lived to tell the tale due to fast deployment of their oxygen masks. The cabin crew were confused as the masks didn't deploy in the passenger cabin.
Happy memories :-D
John Doe 12: The cabin crew were confused as the masks didn't deploy in the passenger cabin
It was Ryanair. I bet none of you had paid the £0.99* Oxygen Mask fee.
*(£0.99 at time of booking, with approved credit card only. Can be purchased in-flight** for only £199.99.)
**(while stocks last. Availability not guaranteed. In cases where stock is not available, scratch-cards will be offered instead.)
All the sprinkler heads going off at the same time only happens in bad movies. Each sprinkler head has a heat activated trigger that keeps the water valve in each head closed unless the air temperature at that specific head rises above the trigger value. This system was designed a long time ago when elec-trickery was understood to be unreliable in a crisis, so no common signals for false alarm disasters.
Still a dumb idea to use water, when CO2 is cheap and plentiful. Too bad the horns that announce its release are so loud the vibration can damage the equipment (hard drives mostly) it is there to protect.
There are two types of sprinkler head - the common type - heat activated that works as you described and the normally dry type where the sprinkler heads do not have valves - instead a single valve supplies water to all the sprinklers when it is activated. This second type is often connected to a dry riser that fire engines can connect to. This allows fire engines to drench the whole property without carrying hoses up many flights of stairs.
Duncan, your information is incorrect. Dry systems use the same heads as wet. They are just charged with compressed air insead of water. Dry systems are used where the piping systems may be exposed to freezing temperatures.
The only heads that flow are those that are exposed to temps above 154 degrees.
Flow is detected in wet and dry sstems by a sail switch embedded in the main supply line at multiple points.
And stand pipes on the exterior area of a building are used primarily to augment volume when multiple (a lot) of heads have been tripped and the street can't provide proper pressure. Yes, older buildings do usually have external stand pipes to provide a hose connection on the the roof.
IT rooms are a whole different bag a of shit to deal with.
Umm, not really.
A deluge fire suppression system has one valve and 'dry' pipework, once the valve is opened then all sprinkler heads spray.
https://www.vfpfire.com/systems-deluge.php
It's used in places where risk of leaks from pressurised pipework is a "bad thing".
Best fire system I ever saw was a 'hypoxic' or reduced oxygen system, the datacenter had an oxygen depleted atmosphere, five or six percent lower than atmospheric, which made it impossible to light anything that didn't have its own oxidiser but perfectly possible to work in unless you had severe lung problems.
https://en.wikipedia.org/wiki/Hypoxic_air_technology_for_fire_prevention
You are correct about multiple heads operating at once being a rare situation, but you are mixing deluge systems and pre-action systems.
A deluge system is where setting off the system causes all heads to spray water. It's used in very specific high-risk situations where pre-wetting unburned materials is a good idea. It's also used in Hollywood movies for dramatic and/or comedic effect.
Pre-action systems systems have the pipes charged with air instead of water. The heads are still *individually* opened by heat. Water is not allowed to flow unless fire is detected by another system.
A dry-pipe system is similar to a pre-action system, except that once a head is tripped and air starts flowing, water will flow right behind with no need for a separate detection system to trigger the water flow.
Pre-action and dry-pipe are often used if the piping is exposed to unheated areas that are exposed to freezing temperatures (unheated attic spaces, parking garages, etc.)
If your sprinkler head has a small slug of metal (most common in warehouse applications, I think) or has a small glass vial with colored liquid in it, it's a conventional system with individually actuated sprinklers. Or, unless you work in an oil refinery, chemical processing plant, munitions plant, or airplane hangar, your sprinklers are individually actuated.
I was always under the impression that when one sprinkler went off that the pressure drop within the system was supposed to cause the other glass bulbs to no-longer be held under tension thus dropping them out or allowing the bulbs to break owing to said drop in pressure.
I suppose it might depend on the specs of the system and the local regs as to how they trigger and if they can be cascaded like that.
Also on further reflection, having the sprinkler closest to the fire only trigger make more sense to focus the water where the fire is rather than just making everything wet, lowering the total pressure and even total amount of available water.
Fire icon natch.
My thinking about making everything wet was that, if the fire is hot enough to set off the sprinkler on the ceiling over here, it's probably already spread to the floor over there, so immediately soaking the entire area would be the best way to quickly stop the fire from spreading.
It's not very difficult to devise a system that keeps the heads under low pressure (air or water) that the sprinkler heads are constructed to withstand, applying full pressure once one of them is breached, causing the other heads to pop. And this with just a pair of valves.
They are used in attics and other unconditioned spaces like warehouses when they can't be assured the temperature won't dip below freezing. You have a compressor connected to it that keeps it pressurized, and only floods if the pressure falls below a certain point.
Usually there's a 6:1 valve balancing the air and water pressure, so if your water pressure is 80 psi then when the air pressure falls below 12 psi or so the system will "trip", meaning the valve lets water into the dry system. Then you get to pay the sprinkler company hundreds of dollars to come out and reset the system.
installed mandated by ignorant manager.
The manager certainly didn't install it himself.
That said, I really would like to see that guy face-to-face to ask him what the ever-loving frak he was thinking of putting sprinklers in a room full of pricey electrical equipment.
He should have a fireplace installed under his bed.
We all know the old saying : give a man a fire and he'll be warm for a day, set a man on fire and he'll be warm for the rest of his life.
I remember a fire in trunking at an office I worked it. What do you think the software developers did, as the acrid plasticky smoke poured out of the trunking, and flames licked up the wall? Do you think that:
a) they grabbed the fire-extinguisher, a mere 8 feet away, and let rip like heroes?
b) grabbed their phones, and left the office to go to the pub (over the road), hitting the fire-alarm on the way out?
c) stood around admiring the pretty flames?
I’m ashamed to say that the correct answers are: Some (myself included, I’m sorry to say) opted for b. A significant number opted for c. And it was left to the delivery manager to save the day and use the aforementioned fire-extinguisher. No significant damaged occured, and no computers were harmed during the excitement.
My employer specifically forbids anyone without formal fire extinguisher training from attempting to use one - and even then, they beat it into our heads that the primary purpose of a fire extinguisher is to make sure you have a clear path to the door. Only a VERY SMALL fire that is fully visible (i.e. not in ceiling, wall, etc.) should be put out; anything else is an evacuation scenario. The humans are worth more than the equipment.
Everyone had mandatory fire training once per year. Fat lot of good it did, apparently. And it was only a very little fire - a 50cm section of the trunking and cable within was destroyed, the wall had nasty greasy black scorch marks on it. The trunking was attached to a solid wall, the extent of the fire was easy to see.
Didn't stop me high-tailing it to the pub though, to ensure that I had plenty of cold fluid on hand with which, if necessary, I could remove the source of heat and deprive it of its oxidiser. Better safe than sorry.
I read a draft of a UK Government 'official' fire-warning / fighting leaflet'.
It said, and I am not joking, that if there was a fire in a false floor, staff could prise up the tiles and fight the fire using hand-held fire extinguishers.
I, rather abruptly, informed my management , that in the event of a fire under a false floor / in a false ceiling, I intended to evacuate the premises* and call the fire brigade, and that unless this leaflet were supported by the local fire safety officer of the local fire brigade it should be binned immediately.
I don't think the leaflet went into general distribution, fortunately.
As for what the software engineers did or didn't do, fighting fires is demarcation innit? Don't want to annoy the unions, now do we?
* I think my actual phrase was closer to 'run like f*&k', but it was a long time ago.
> I’m ashamed to say that the correct answers are: Some (myself included, I’m sorry to say) opted for b.
Don't be ashamed - b is exactly the right answer. Modern practice is to place the fire extinguishers by the exits. Their sole purpose is to enable you to extinguish a fire that is preventing you from using the exit.
The danger with fighting a fire yourself is that you might think it's out when there may still be bits that are invisibly smouldering and producing carbon monoxide plus other nasties. The fire service will have the right equipment to check.
I've had the pleasure of both Offshore Fire-survival & Offshore Fire-fighting training.
I learned a lot on both of those courses, had to use it a couple of times. Actually handling a fire hose as one of two teams to push back flames, while some team member has to crawl between them to close a valve feeding the fire, while the flames are drawn in & then deflected back over in close proximity to your heads in short drop the hose & at minimum your team & the guy on the floor are fucked, going through smoke filled chambers, been there gone in retrieved survivors (& trodden over the first survivor who found a new role in the scenario as a doormat) the works.
So I'd say I have a lot more experience than someone that just did a course on handling a small handheld fire extinguisher\designated Fire Marshall as for some reason dialing 999/911 when you are 40 miles off the coast doesn't get the same response time as Number 27 Acacia Gardens.
If you can tackle it, or diminish it to escape great, if not get out ASAP & let the trained responders & by that I mean those wearing the full BA kit & PPE take control.
Electrical fires are "interesting". I had an interesting conversation some years ago with someone who's job was designing fire alarm & control systems - that's bespoke systems designed to suit individual sites. At the time, they were just finishing the commissioning of a fire detection system onboard an NGO ship. Most of the below is extracted from that conversation.
You have a source of energy (heat). You have a source of oxygen (unless the room is very sealed). You have a source of fuel (the "whatever is on fire).
Gas drench systems (Halon or modern equivalents, CO2, oxygen depleted atmospheres) only prevent the combustion - but leave the source of heat in place. The problem with this is that a large proportion of materials involved contain chlorine - that's the C in PVC. If it can't combust because of the suppression system, then it will still decompose and the components will float around as free radicals - which will react with anything they can. So unless you remove the power as well, then you might as well not bother as the chlorine will have destroyed anything exposed such as all the contacts on connectors.
As most equipment is (or should be*) made with self-extinguishing materials - e.g. PVC has additives to make it self-extinguishing - then all you need to do is to remove the power source and the fire will go out on it's own.
So a reliable way of putting out the fire is to ... remove the power quickly. That's not "trigger an orderly shutdown so things are powered off in the next 10-20 minutes, but "pull the plug, NOW". Naturally, you then get into a situation of trying to balance the risk from fires with the risk of damage to data and service outages of doing unintended uncontrolled shutdowns.
* AIUI modern electrical/electronic equipment is supposed to use self-extinguishing materials. You can easily tell if (e.g.) a sample of cable is self-extinguishing. Just take it to a well ventilated area and apply a flame. It'll probably burn and will emit horrible black smoke. But remove the flame and it should just go out on it's own. Older PVC cable will carry on burning. And I strongly suspect that some "cheaper materials imported from certain countries" will also carry on burning.
"About shutting off the power -- isn't that what that big red button by the door is for?"
No, that is for ordering the 'Big Mac and Fries with a large Coke'.
The shut off the power button is the one under a (locked) plastic cover, in an office with a locked door that only the caretaker has access to , but you can see it through the reinforced wired glass panel, next to the fire(wo)man's axe. You have no choice but to smash through the plasterboard walling (because although the door and its lock are SEAP* approved the walls are standard partitions), and the filing cabinets that line the walls in order to gain access to the one feature that will save the company form going bankrupt.
That's 'security' for you. :oD
*Security Evaluation and Approval Panel, I think
When my father was base commander in Australia they had an electrical fire in the main power switchboard before breakers etc. They could put out the fire with a CO2 extinguisher but they couldn't stop the arcing. So my father called the electric company and asked them to shut off power to the base (and neighboring town) but they didn't want to. So my father said that when they ran out of CO2 they would throw a rope around the wires leading into the building.
They shut off the power.
1st incident:
In the mid 80s I was a computer operator. One night a tape controller caught light but no alarms were triggered. The smoke was being sucked across the ceiling into the AC vent, right across a smoke detector. The next day we had a company come in to check out the system, turns out none of the smoke detectors were connected to the fire control system so no Halon dump, not only were they not connected there wasn't any cabling to connect them to.
2nd:
Late 90s. A terminal caught light in the computer room of the company I was at. For some reason rather than the alarms going off and the Halon dumping 60secs later it dumped the Halon first and then wait 60s to set up the alarms. Not so good for the two guys in the room at the time.
3rd:
2012ish and there was a false alarm in the hosting provider for my current company. The FM200 was triggered but they had fitted the wrong horns to the valves, the noise they created was enough to destroy most of the hard drives in the SAN, cue several weeks for data recovery, we had a duplicate DC in the US so no one saw any downtime.
20+ years ago I worked for a niche energy company: their large, critical mainframe installation was housed in a new build, old-factory style building (series of roof ridges, high ceiling) in attractive red-brick. Far too big to be able to afford the halon (and in any case now, it's very difficult to find any non-CO2 material that will be licensed - many existing installations may no longer legally be refilled if discharged), and impossible to displace enough O2 quickly enough with a CO2 system to be effective. Any effective CO2 flood system would literally blow everyone off their feet - and how to avoid imploding their ear-drums?
Their solution: VESDA that triggered a 10s delay, followed by total electrical power disconnection, then another delay of about 10s, followed by water sprinkler from a dry-riser system. It's usually *fairly* easy to dry out circuit boards that have been soaked in clean water, with minimal losses.
Except that the VESDA was *so* sensitive that you were NOT allowed to lift floor tiles without disabling the VESDA first - enough dust trapped in amongst the cables to trigger the alarm=>cries of anguish all round. It happened once, but the visiting engineer's foolishness was stopped by a very smart colleague who got to the disable button before the water started. Took a while to restart everything after the crash power loss though...
A very large computer hall had signs on all entrances and inside "NO HOT WORKING", as the smoke detectors were very sensitive. (It was in the days of Halon fire suppressant systems of the 'get out or suffocate' variety).
One 'bright spark' (did you see what I did there?) plugged in his soldering iron. Waiting for it to get hot, the lead vapour liberated triggered the alarm. Fortunately someone was quick enough to disable the halon system before it discharged. The electrician was escorted off the premises and banned for life.
The hall did have several tens if not hundreds of millions of pounds worth of kit, and housed some UK Critical National Infrastructure as well.
I worked in a computer room in the early 80's when Halon was all the rage. This was a VERY large computer room, the equivalent of several large aircraft hangers, with multiple main frames, tape room, printer rooms, etc. It was fitted with the "state of the art" fire suppression system. There was a control panel that prevented the halon from going off when people were in the room - well it gave you 45 seconds to get the flock out of there when the alarm went off.
The system was to have bulbs of halon in both the ceiling and floor voids. These bulbs had pyrotechnic devices to shatter them when triggered. Translations - a small explosive charge. They were wired in series with a trickle charge to show that the circuit was complete. It all showed up on the control panel outside the doors. What could go wrong?
Well, when the control unit has a hissy fit and fails dangerous, it sets off the charges. Which it did. Without any warning whatsoever. Some, but not all, the globes of halon exploded. Some didn't which from a fire protection point of view was a problem. However, a bigger problem for two of the operators was when they did go off close to a person. One of the main frame controllers was sat at his desk when the globe above him blew. He was thrown out of his chair and broke his arm.
Worse was to come. A lady in the tape room was reaching in to a tape unit (remember those ones with 2400' tapes?) when the globe beneath here exploded. She survived but here dress didn't. She ended up in her underwear!
Everyone had a ringing in their ears from the bangs, made worse by the rather belated sirens going off warning us to get out.
Icon - well obviously!
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You peer through the haze, find the big red button and press it.
The extinguishers go right off,
filling the hot-box full of pretty boxen with blinken lights
with an enormous volume of powdery stuff,
don't they Kingsley.
Really happened near the end of a party at work.
The "fire" was the blinken lights seen through glazed eyes.
Took weeks to clean up the mess.
In answer to the question in the title, you don't.
In the 20+ years that I worked for a tier 1 telco I never saw fire suppression systems of any kinds inside the equipment rooms.
There would be the occasional dry powder extinguisher clipped to the wall by the door, but no water sprinkler or gas suppression system anywhere.
There was always a VESDA system that was routinely checked for correct operation, and the occasional false alarm that triggered a 5 truck call out from the fire brigade.
Company OH&S policy was very clear: the equipment rooms do not have fire suppression, you shouldn't be in there unless absolutely necessary, so in the event of a fire get out quickly.
The other thing I never saw, or even heard of, was a fire in an equipment room.
All equipment and cabling going into service was tested (often to destruction) before deployment so as to sure that it not only met spec, but was safe.
Maybe the IT crowd have different priorities.
Not an equipment room as such, a heat soak room.
That was in a factory supplying Telecom with teleprinters. A large number of units assembled in frames without covers were heat soaked for a time, operating with a punch tape loop. This was in the factory with a couple of hundred workers through the day, so couldn't use halon. There was risk of something exploding or catching fire operating at elevated temperature. And yes, from memory it was a large red button.
Could tell you about the time a large electro exploded while the Sagem engineer, our head engineer and a senior tech were all leaned over a teleprinter listening to a ticking sound, while it was being tested. Not a fire, but a really loud explosion is much more fun and a mess of yellow liquid electrolyte evenly over all three.
We had so much fun at that place, ever had a gold plated screwdriver ??
A chap I met on holiday* many years ago was a 'management consultant'. He'd been presenting to management at a BOC plant where they liquified oxygen. Asked to leave the room briefly while there was a discussion, he accidentally leant on the fire alarm. He said: "I've never seen so many people run so fast before in my life". When you 'make' liquid oxygen, you don't hang around to see if it is a false alarm, or collect your coat, keys etc. before evacuating the building.
Nice chap. He owned up immediately, of course.
*(Trekking in Iceland, central southern highlands)
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