Schneier on Security
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April 21, 2010
An odd burglary prevention tool:
If a burglar breaks in, the system floods the business with a dense fog similar to what's used in theaters and nightclubs. An intense strobe light blinds and disorients the crook.
Mazrouei said the cost to install the system starts at around $3,000.
Police point out that the system blinds interior security cameras as well as criminals. Officers who respond to a burglary also will not enter a building when they can't see who's inside. Local firefighters must be informed so they don't mistake the fog for smoke.
EDITED TO ADD (4/21): I blogged about the same thing in 2007, though that version was marketed to homeowners. It's interesting how much more negative my reaction is to fog as a home security device than as a security device to protect retail stock.
Posted on April 21, 2010 at 12:55 PM
• 54 Comments
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Its an odd one and I am unconvinced as to its value.
That said there are quite a few Physical Security Professionals I've met with in the past few weeks who are quite keen supporters.
To me, this seems it could be dangerous.
If it blinds crooks, it blinds anyone else who may be inside. Imagine someone blinded trying to get out who then comes across a panicking crook who likewise can't see.
I'm torn between silent alarms and loud alarms. A silent alarm may help apprehend a crook, but if someone is in a building with a crook and doesn't know it they can be in danger....whereas an alarm notifies them and sends the threat running. Basically, the fog and lights would clearly notify someone, but may send victims and perpetrators running into each other in a panic.
I'm with GreenSquirrel--unconvinced. Then again, I'd like to hear the Pros from the people who are keen supporters. I can think of some pros, which my gut tells me are outweighed by the cons.
The link doesn't but here is something similar http://www.concept-smoke.co.uk/ There have been other systems that dispense tear gas or OC (Burglar Mist in the US, BurglarSpray in the RSA). There is another gizmo used at some U.S. government facilities that rapidly fills protected spaces with a soap suds sort of foam. The foam is interesting in that it also defeats NVD and FLIR. Some especially defensive agencies also drop a coil of razor ribbon concertina into the foamed space to make access and egress all the more difficult.
@ HJohn at April 21, 2010 1:19 PM
None of the people I spoke to had actual reasons to say why it was good - just that it was "a great idea." I found this a touch strange.
I seem to remember reading something about it in RiskUK magazine (which is a bit tedious but *can* show trends in the physical security area, mostly its manned guarding though). Again, I dont remember enough details to say why it had been touted as a good idea.
The only advantage *I* can think of at the moment is for an uninhabited facility.
If you have an internal clear zone and an intruder breaks in they can be imobilised by the fog and strobe - ideally long enough for a response force to arrive and take appropriate action. As far as I am aware there are some mobile phone shops (*) in the UK that use this system in their show rooms to prevent people breaking in at night and stealing expensive equipment.
the downside with this, as mentioned, is that anyone responding isnt going to go in until the fog / strobes have lifted so it would only work if the intruders were forced to pause in an area close enough to the perimeter that the response could grab them as soon as it cleared.
Still doesnt do it for me, no matter how hard I try to justify it.
(*) purely based on anecdotal evidence. I have no reason to doubt the people who have told me this but also no reason to think they are telling the truth.
Reported (here?) years ago - the lawyers decided that if an intruder triggered it and injured themselves they could sue the store.
Same reason you aren't allowed to put down bear-traps anymore for trespassers ;-(
@GreenSquirrel: "The only advantage *I* can think of at the moment is for an uninhabited facility."
I was able to think of two, the uninhabited facility and also to buy time for authorities (inhabited or not). With the latter, it seems a danger to anyone else there.
Even if people being there is rare, i definitely think it would be a murphy's law scenario. It would happen when one person was there for a rare reason. Perhaps the person that left before them thought the place was empty and set the alarm for ARMED-VACANT (we had an alarm years ago that distinguished between ARMED-VACANT and ARMED-NOTVACANT, meaning motion sensors did not activate throughout the building but new entrants still had to disarm when coming in the door) when someone was still there (a janitor did this to me once).
I definitely think panic could be dangerous.
I first saw one of these systems installed at a video rental store about 15 years ago (after a string of B&Es), along with a more traditional alarm system (motion sensors, glass break sensors, etc).
I thought it was pretty interesting at the time, having never heard of such a thing, but I don't really know how effective it was. As an aside, the store is now out of business.
@NobodySpecial: "Reported (here?) years ago - the lawyers decided that if an intruder triggered it and injured themselves they could sue the store."
There was a case a few years ago where a couple had a problem with break ins and they determined it was someone acquainted with them since the person knew when they were away. So they put out the word they were leaving town and hid. The confronted and video taped the intruder. The intruder attacked them and the husband fought back, hitting him with a ball bat.
The video was used against the husband in trial. The court ruled that the husband used too much force beyond self defense (if I recall, he hit the man and knocked him down, and hit hiim again when he appeared to be trying to get up). Both the intruder and the husband received the same jail sentence. Arguments regarding the inability to think rationally when fearing for his safety and his wife's fell on deaf ears. I personally can see how someone scared for their life wouldn't want the person attacking them to try to stand up, but i admit i wasn't on the jury for the trial.
A little difference, but same concept.
You can't really trust the law to be fair, sadly.
Some home alarms have that. A friend of mine has two dogs, so the "NOTVACANT" mode is required unless they are going on vacation and they board the dogs.
This is a profoundly stupid idea.
It's a really dumb idea. As mcb pointed out, there are similar systems that dispense OC gas. I highly recommend those as they've proven quite effective deterrents. The guys on the show "It takes a thief" (i think that's the name) install them often. Security consultant Jim Gover mentioned a variation on it that one VP did at his house.
The VP's "safe" room was his bedroom. On the outside of the door were tiny holes connected to an OC canister. His wife was to get herself and the kids into the room, prep the shotgun, call the cops and if crooks tried to kick in the door, activate the OC. It would hit their eyes before they realized what's happening. OC is bad ass stuff. A fog/smoke dispenser gives no visibility with no real benefit in return. An OC dispenser reduces visibility while providing the benefit of giving the crook pain only a kidney stone or (maybe) air taser can beat. I recommend 3 million Scoville Heat Units & buy a quality brand. If you might use a taser in conjunction with OC, make sure it's 5 million SHU OC or they might catch fire and it's your ass in court. :(
At the least, flooding the area with OC means they won't steal your stuff without paying some price for it. ;)
@ HJohn and Greensquirrel
I guess I could be a keen supporter, but only in very specific applications. Occluding smoke or fog is better used against burglars than robbers, and in unoccupied spaces rather than those also occupied by innocents. Common law suggests that even a burglar is entitled to escape a burning building, so a skillful attorney might argue these sorts of tools present a real risk accidental injury, or even constitute deliberately inflicted pain and suffering. A mix of optical and accoustic disorientation devices might work as well and still allow a bad guy to depart (I've long thought a car alarm's siren should be installed under the driver's seat inside the car). If you'd rather a potentially dangerous perpetrator stick around to speak with the authorities there are remote controlled Taser mines http://www.gizmag.com/tag/taser/ Not to send an incorrect impression, most of us physical security guys only get to muse on this sort of thing, but if we ever get a green light and a prodigious budget we're ready to roll...
Sounds like someone in the night club supply business had a bunch of leftover inventory and tried to re-brand it. Maybe the criminals should have to pay a cover charge, another useful security deterrent?
According to colleagues who work in the physical security distribution sector, the objective is to deploy the smoke during an incident that occurs out of regular operating times to interfere with visibility and reduce the capability of a burglar to locate product worth stealing in a retail environment.
Simultaneosly, it increases the difficulty to find the exit unless the burglar is very familiar with the layout, increasing the likelihood that the burglar will be on premises when there is response from security or LEO.
My colleagues wouldn't comment on the effectiveness of the control (they rarely do), but they did say it is gaining popularity here in Canada.
It seems that in that narrow set of circumstance it would be useful, but it seems that would also require significant design of the property to reduce the success of smash & grab style burglaries, and to increase the ingress and egress time and complexity for the burglar; those activities would, on the surface, seem to be far more valuable investments since the set of threats it protects against are more generalized and affect the business around the clock, not simply when the premise is unoccupied.
"I first saw one of these systems installed at a video rental store [...] As an aside, the store is now out of business."
I don't think security is the reason they are out of business!
I've written you several e-mails...I know you're super busy...I'm not some freak...just the opposite...I read your article, and beleive you to be the only person to help me solve a 6 year old case, in which, I had "web-tv", and was told to this day, it couldn't be hacked,(no hard-drive) I have tons of proof it CAN be hacked, & was 6 years ago & i was beaten & thrown in PRISON for a year, for criminal, terrorist threats, and stalking! I swear to you sir...It's been a living Hell, X-friend & boyfriend hackers did this to me, and I still cry every day! I was tortured in prison, they e-mailed threats to the police as well, Please for the LOVE of GOD...Help me. I Must countersue & get my good name back, I believe there would be a large settlement against MSN-Web-TV, for LYING to this day!! I hate talking on this machine, but feel I MUST contact YOU!! I trust NO ONE, Please send me a P.O.Box address, anywhere, where I can converse with you...PLEASE. You can keep the money, I just want JUSTICE, you'll understand when you know the HORRIFIC things they did to me..HORRIFIC!! I'm sorry for contacting you so much, I'm NOT a STALKER, just a DESTROYED, middle aged women, hiding in Hawaii....I would say talk by phone ..but I'd just Cry, & Cry, &Cry (808)4314274
Agreed, this is a silly idea for many of the reasons already listed here. If I were malicious person and I knew a building implemented this system, I would intentionally set the thing off multiple times until the owners got rid of the system (I'm assuming fog replacement would cost money, if fire crews have to get involved every time it goes off it will become a problem for them, etc etc)
In a previous job (around 10 years ago) we had one office that was constantly being burgled and the PCs stolen. In desperation (the insurer was threatening to withdraw cover) we installed this device.
The supplier arranged a demo and, when it goes off, you're instantly surrounded with imprenetrable (but harmless) smoke and you have no idea what's around you. In addition to the strobe, there's a very loud recorded message advising you to stay completely still. Trust me, you're not inclined to disobey!
It may be a coincidence , but that site wasn't burgled again (at least not on my watch).
@Tom Mellor: It may be a coincidence , but that site wasn't burgled again (at least not on my watch).
I'm just curious... did a burglar ever trip the alarm and trigger the fog, or did the incidents just stop dead?
@HJohn, I don't recall the device being tripped by a burglar. It's tempting to think that the warning signs have as much effect as the device itself.
We'd already tried security guards patrolling inside (the burglars got in and out before the guards could get help) and we considered CCTV (the Police suggested this was a waste of money unless we particularly wanted to collected videos of youths in dark clothes and ski masks).
I dunno. Fog and strobes? That's it? It needs something. The Bee Gees... Gloria Gaynor... Donna Summer... where's my Ohio Players CD, hmmm.
This would make robbing a jewelry store so much easier and safer.
The crew uses wearable videocams to thoroughly case the place. They come back another day when the store is open. One of them triggers the alarm, and the others swoop in with baby sledges and bags, feeling their way to the choicest loot, smashing the glass, grabbing the goods, then feel their way to the front door and out, acting like customers escaping some disaster. Nobody is going to stop a normally dressed person carrying an attache case.
Meanwhile, all potential witnesses, both employees and customers, are groping around in confusion.
A classic case of "security through obscurity"
Nice one. There are many variations on your scheme that any common crook could pull off if they knew where the product and exits are. They usually do in retail situations. A more sophisticated approach for assets that are worth it would involve gas masks from Lowes or cheap scuba gear along with a decent set of used thermal goggles w/ infrared-filtered flashlight. Altogether that would cost at least $5,000 per person, but for one or more high value targets protected by smoke they might get a good return on investment.
I'm sure some would do it just for the fun of going in like Sam Fisher. Hell, I would... during a pentest... with legal immunity. ;)
@nobody special & @hjohn
The rule in most of the U.S. is that you are not allowed to defend property with lethal force. Although you can protect yourself or other people through use of deadly force, you cannot leave lethal traps to protect your warehouse or shop or whatever if there's nobody in it.
See Katko v. Briney, for instance.
So, a bear trap might run afoul of this rule, but I would be surprised to find that legal liability attached simply because a burglar stumbled around through an alarm fog, tripped, and hurt him/her self. On the other hand, if the device malfunctioned while actual customers were in the shop, and one of THEM tripped and fell, forget about it.
@ Gary Capell at April 21, 2010 7:13 PM
ROTFLMAO - brilliant and I wish I had thought of that :-)
@ mcb at April 21, 2010 2:12 PM
"I guess I could be a keen supporter, but only in very specific applications. Occluding smoke or fog is better used against burglars than robbers, and in unoccupied spaces rather than those also occupied by innocents."
I kind of agree with that.
The problem I see with it is that once deployed, and your intruders are stopped in an area, you need to make sure that a suitable response is around them so that when it clears they cant escape.
Quite rightly no response team are going to go into the fog/strobe area while the system is active, its much too risky.
The biggest downside, is that this seems an expensive, overly technical and prone to error way to create what is effectively a trap room to detain intruders.
I've seen something similar in the UK called the 'Smoke Cloak'. The only problem is, when it goes off it also sets of the fire alarms....
This was used in the jewelry shop on London's Picadilly that was robbed by the bike gang the other month. The smoke went off when they started bashing the windows with a sledge hammer. One the window was broken through a few minutes later it started clearing. The area of the window was small enough for them to find the jewels without the smoke causing a problem.
Thicker windows and a faster police response would be a better solution in this case
"I've long thought a car alarm's siren should be installed under the driver's seat inside the car"
Wouldn't fly because of the added chance the driver would cause an accident in the case that the alarm went off accidentally. I think this is also why a car alarm is not allowed to immobilize the car if the car is already running (in my jurisdiction, anyway, that's how it works).
There's a business around the corner from me that used to sell and fit these smoke alarms, was very amusing one morning when we went past to see the staff all sitting around outside in the car-park with smoke billowing out the door. Yep, they'd let one off in their loading dock by accident.
I have a pair of peril sensitive sunglasses that, in the event of any danger, black out completely preventing me from seeing anything that might concern me. It's help me develop a laid back attitude to danger.
These cats at Flashfog, doing the same thing, are just these guys you know?
'used in Canada and Europe for years' Really?
Might it have a use within the trailers of lorries? Break in and smoke goes off making it hard to locate and remove the load. The smoke could be coloured to differ it from fire smoke.
I was going to suggest in cars to prevent theft but accidental discharge might be a problem.
The Smoke Cloak and other similar devices do work when used correctly (and don't always set of smoke detectors).
The problem with "pepper spray" or "CS Gas" and most of the foaming systems is residue, that can be difficult (if not dangerous) to clear up, and can effectively "right off" stock, furniture and fittings (so you might as well burn the place down ;)
However if you have a high value target that has been hit one or more times you have the problem of the insurance cover being withdrawn, unless you do something. So people "will step up to the next level" after ordinary alarms such as low end debilitating systems (fogs / strobes etc) provided the liability increase is close to zero.
However a debilitating system such as the smoke cloak on it's own is not that effective in that people can get down on hands and knees and crawl out the door. What makes it effective is having several strobe lights and very loud sound sources going off in short bursts randomly.
The result is often not just disorientation but full on puke making debilitation. However nowhere near as good as lobbing in a couple of "flash-bangs" or the more gentle stun grenades.
There is however a downside to debilitating systems, unfortunately you have to be a bit careful with flashing lights, as your intruders may suffer fits and seizures if they have a tendency towards epileptic fits etc.
And as some of you "heavy rock deffo's" are aware sound at sufficient volume and the right frequency range can effectively make it feel as though your guts have turned to liquid and induce projectile expulsion at both ends of the alimentary canal (this idea is one behind some of the so called "Non lethal weapons" for crowd control etc).
But even sound can be taken to far, there was a system under development in the UK back in the 1980s it used a couple of powerful ultrasonic generators that had a frequency difference that was equivalent to that of "brain waves".
It was not just capable of incapacitating people but actually caused fits, seizures and death in a very short time.
man, everyone is so negative about the fog! Didn't you play Splinter Cell? Just make sure you've got some thermal goggles and you've got an advantage over the intruder.
I remember seeing this in use on an episode of "It Takes A Thief" (?). On each episode of the show, a former thief would be hired (with the subject's knowledge) to break into his or her home or business to show how easy it was. Then alarms, locks, cameras, etc. would be deployed and the thief would attempt to break in again to test their effectiveness.
The fog (without strobe) was used once to help protect an automobile warehouse, and it was very effective. It was completely unexpected and made navigating the warehouse nearly impossible. If a would-be thief doesn't cut and run immediately -- and this one didn't -- he's very likely still to be wandering around when the cops show up. Even if he eludes capture, the attempted theft is cut short or at least made less effective (it's hard to steal the most valuable stuff when you can't find it).
It sounds silly, but it seems to work.
"It sounds silly, but it seems to work."
But is it a cost effective measure?
Does it provide a better enhancement than, say, stronger door locks?
@GreenSquirrel: "Quite rightly no response team are going to go into the fog/strobe area while the system is active, its much too risky."
Which complicates things if someone is injured and needs medical attention. Try not to bleed too much until the smoke clears.
My thought here is just wait until it accidentally goes off during a fire and the fact that the house is unnavigable kills everyone inside.
OK, I'll bite. Wendy, you remind me of a friend who unsuccessfully fought for justice in the courts, pro se (in her case, needing medical expert advice). It is a hard row to hoe, but in honor of her, I will take time to pass on my two cents as a computer security amateur. (I am not a lawyer and this is not legal advice, just friendly advice.)
Two key questions: do you have a lawyer, and do you have a copy of the original email, including email headers, for which you ended up in prison? (Do I even understand your situation correctly?)
First, it sounds like you need a lawyer as well as a computer security expert if you're going to make any headway. The computer security expert can help direct the lawyer's discovery efforts towards the signs that MSN-Web-TV is lying, if they are, and ensure that you get the original copy of the emails or email logs which you would need for any defense (or to overturn your conviction.)
Second, for a computer expert to get involved, they would first need to be convinced you aren't crazy/paranoid/mistaken and that there is a real injustice here. I'm not sure how you do that, but I will circle back to that at the end of this post.
Assuming you were wronged, there are three basic technical scenarios I see that are consistent with your claims:
One, that MSN-Web-TV systems were hacked. This seems to be the route you are headed down but frankly it is the most unlikely of the three scenarios. A computer security expert could help direct a lawyer what to subpoena to prove this, but if you are doing it pro-se, I doubt passion alone will suffice to get to the bottom of this without both a good lawyer and a good security expert.
Two, and much more likely, is that someone forged an email to appear as if it were coming from you. This is pretty elementary computer security issue and any computer expert should be able to discern this if they can obtain the original email with email headers received from the police (hence your need for a lawyer.) Frankly, the prosecution should have had to show this was not the case in your original trial. No hacking of MSN is required, or really hacking of any kind. If you or your lawyer can obtain the original email, with all email headers intact, a computer expert (or even IT person) can quickly look at your email and tell you whether you have a potential case and whether it's worth more than 10 minutes of their time. (Actually doing full forensics on the email headers would take a lot of time and professional expertise to hold up in court, particularly if your adversary is good, but simple signs of email forgery are often visible pretty easily to any skilled IT person interested in computer security, and they can tell you whether your case goes along these lines and if you can describe that, it will help a computer security expert know quickly if they can help you.)
Third, and almost as easy as number two but far more difficult for you to deal with from a defense perspective, is that someone close to you obtained your WebTV access credentials (username and password) via guessing or spying on you and used them, perhaps even from your residence (since boyfriend/x-friends are involved) to send the terroristic threats.
If someone sent terroristic messages from your WebTV account, using your name/password, from your home, it would be very hard to find evidence one way or another that you pressed the keys or that someone else did. No computer security expert I know can help prove that (unless there are somehow reliable electronic records related to some other activity you were doing that place you outside your home at the time MSN records show the messages were sent from your home, or MSN keeps such detailed logs of user activity that they could record the timing of each keystroke and an expert could show a different timing of the keystrokes.) I would be surprised if you could overturn an existing ruling even with a computer expert's help, unless you had a really good lawyer.
Finally, if you wish to get the help of a computer security expert, particularly without paying for it, that is always a tricky thing. You will be 100x more likely to get help if A) you can obtain via lawyer or some sort of discovery or trial record, the original email *INCLUDING ALL HEADERS* containing the threat for which you were prosecuted and B) if that email contains signs of exoneration for you.
Also, you will be mildly more likely to get help if you can indicate you have a lawyer. Any computer security expert is going to want to make their time spent on the case very efficient, and it will be far more efficient use of their time to talk to a lawyer than to talk to you about all the particulars of your case and the legal implications, unless you find someone particularly kind and non-busy, which is fairly unlikely. If you have a lawyer, the computer security expert knows they don't have to deal with the emotional ("cry cry cry") side of this issue and they can focus on the expertise you need to get justice you deserve.
That said, most computer security experts, and even garden-variety IT security-interested people like myself, can take a look at the email headers and know within 5 minutes if you have an easy case or a hard case. If you have an easy case, there's a much higher chance any well-meaning computer security expert will take it on or help you. If you have a hard case (falling into computer security categories 1 or 3 above, or trickier cases of forgery in category #2), you will have a much tougher time getting a security expert to help. So my advice is to start by pursuing getting that original email and have a clear understanding of whether that's ruled in or out for your defense, before expecting to get much of a security expert's time, as that's the most likely way you can get a true security expert to believe in your cause and to help further.
It has its merits, mainly the surprise and disorientation factors though I think you will have a great product if you combine the smart water from the unique ink pen story into the sprinkler system and add the fog :-)
@Someone who cares " have a much tougher time getting a security expert to help"
This isn't true besides what she needs isn't a "security expert". She needs is her own investigator who has mad skills.
Try Steven Rambam at Pallorium http://www.pallorium.com/. Don't know if he's cleared to work in HI but he has affiliates everywhere.
@ Someone who cares
It seems you're only trying to be helpful but responding to communications from obviously disordered strangers tends to strengthen their delusion which does nobody any good. Frankly, it would probably be better for the OP if the Moderator removed the original post, your reply, and mine to you. Be well.
Smokecloak is great fitted in shed to protect motorbikes after got broken into and racing bike stolen filles shed in about 15 seconds best thing i have ever fitted
Instead of the fog, it could be useful to fill the air with something that stinks. A police dog could catch the crook later.
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I work for a company that has a chain of petrol filling stations and we have fitted SmokeCloak to several of the ones that have suffered repeat out-of-hours attacks and it has successfully prevented stock loss in every case where it has been triggered.
You quite often get the smash and grab raid where offenders smash their way in, lever open the cigarette storage containers and flee before the police arrive. The smoke system slows down the time taken to find the goods enough that the police can get there.
Most thieves aren't organised enough to get IR goggles or bother about that sort of thing so it can be very effective
1. In the USA, at least, a fog device will set off most fire alarms. The cost of a 'false alarm' that sets off the fire alarm can be significant - many jurisdictions charge for a fire alarm response by the fire dept.
2. if the burglar knows you have the smoke system, they force it to go off a few times, you quit servicing it and then they go into the space. I've seen similar response to faulty HALON fire suppression systems years ago; the owner of the system eventually refused to recharge the HALON after several false alarms/discharges.
3. The police have to be informed that the system is in place; otherwise the first arriving patrolman simply calls the fire dept (See #1, above)
4. Many fog systems use vegetable oil as the (non-lethal, non-poisonous) fog agent. However, cleanup, especially in a place like a legal office, library or electronics store, could be significant.
5. I would want certification (and some sort of insurance) that the fog agent is non-allergenic. One allergic person an a fogged area could put a proprietor out of business, if injured.
It just doesn't seem practical to me.
I tried one of these systems back in about 1998 or so. I recall it as very effective. The system triggered, and within seconds I could not see my hand when I held it up to the tip of my nose.
The chemical used was glycol-based and completely odorless, tasteless and not irritating in any way.
Night-vision goggles (passive light amplification) will not defeat this system, but IR goggles (active IR illumination) might, if the dispersed smoke is transparent to IR light.
Fog systems have been used in Europe for a number of years and have been most effective. The issues mentioned here are not valid if the devices are installed properly. Some consideration must be given as to the objective to drive the burglar away. It is much more complex when used in an environment where customers or persons with no knowledge of the systems are involved. but some companies have successfully implemented them. Look at Protect systems of Denmark's growth over the past few years and you can see there is a market demand for this type of device.
The security fog systems are very effective and the only security device that actually prevents a burglary.
Other security devices are aimed at making entrance as difficult as possible or to identify the burglar but none of these prevents the actual burglary once the burglar is inside. The Security Fog does!!!
What happens is that the burglar will realize that he can't see anything (including finding the exit) if he doesn't react immediately. He will therefore alsways turn around and flee the way he got in.
Result nothing is stolen, everything is in its place and you don't have to clean afterwards, just ventilate and the fog disappears.
The company I work for installs these systems.
Earlier, a few people mentioned that no reasons were given as to why this system is "good", and I believe many have misinterpreted how these systems should be installed to be effective.
Installation should be done to prevent theft - not to trap a burglar in; a key point in the use of these systems is to force the intruder back out the way they come in, hopefully empty handed.
As noted by a previous commenter, Service Stations stocking cigarettes are targeted in "Smash & Grab" styled attacks.
As a case study, we had a client who had this happen, systematically for months - every few weeks.
The SmokeCloak system (the system we install) was set up; when they next broke in, they fled empty handed when the system was activated.
They have never returned since.
Overall, the rapid filling of the enclosed space closes the time-gap between alarm activation and the alarm response, with an active system to prevent a continued presence at a property where a crime would normally be continued to be carried out.
Fire systems DO need to be modified to accept these, as any decent installer will tell their client.
Used correctly, these systems are one of the best reactionary tools available to prevent theft after a break-in.
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