From the mind of Gabriel Shear
Tuesday, October 27, 2015
Life Safety, Friend or Enemy?
Every day we go on about our way, moving in and out of buildings that serve a multitude of purposes. Very few ever take the time to look at these buildings. How they’re constructed, what they have in them, what they have in common (what they don’t).
Looking around though you will begin notice certain things that exist in almost every modern building. Things like fire sprinklers and exit signs above doors, emergency lighting, fire alarm pull stations and much more. The reason they have these things is due to the fact that almost every modern country on earth has some sort of life safety code.
These codes are created to make sure that buildings don’t become death traps for the people who use them. Things like fires are usually the first thing to come to mind. Now prior to modern life safety codes, a fire within a building could (and did in a lot of cases) mean the death of people trapped inside. Now with sprinkler systems and fire extinguishers within reasonable distances along with lighted exits, a fire in a building is usually not long-lasting and people can find their way out safely.
You might be asking then how can something that save lives and protect people and property possibly anything but good?
Well to begin, central to life safety is the idea of free egress. This basically means that you can’t keep people from leaving the building under any circumstances. Very few places are exempt from this rule, mainly prisons and jails (for obvious reasons).
Making sure people have the ability to freely exit a building under any circumstance means a few different things. First, all the doors must open outward. This feature along with the use of panic door hardware also know as “crash bars” makes sure that in a panic people won’t be crushed against doors that they couldn’t open as others behind them blindly pushed forward trying to escape. This feature has to work even when there is no electrical power. So these systems are mechanical.
In places that use automatic sliding glass doors this becomes a problem when there is no power. Most people don’t know that the sliding doors will actually pop open if pushed from the inside. Once again this is so people aren’t crushed against them during a panicked rush for the exits.
The second reason is life safety also overrides building security. Even if a door is locked from the outside it must open from the inside regardless of who is opening it. Keyed locks must freely open from the inside to go out towards the exit(s) of the building. In electronic security, use of electronic locks must not prohibit free egress. This means magnetic locks must open when the fire alarm is triggered as well as provide free egress during normal use. Usually code require a minimum of two ways to unlock the door. Normally a passive infra-red motion detector is used to accomplish normal egress unlocking, along with a backup exit button that physically breaks power to magnetic lock in case of failure of the motion detector.
You might be beginning to see how this idea of life safety might be used by someone to get into an area that normally would be secured. By manipulating mechanisms normally designed to protect people. Entry into secured areas is possible. Magnetic locks are very susceptible to these kinds of attacks because at their core they require power to remain secured and are easily unlocked by removing that power. Another common attack vector is the request to exit sensor. This device’s purpose, is to notify the access control system that a person is exiting the door from the non secured side and to ignore any alarm set off by the door opening without a valid credential. Sometimes they are set to unlock the lock if triggered. The majority of these sensors are passive infrared motion detectors and can easily be fooled by objects waved in front of it through gaps around the door. Particularly the gap at the bottom of the door.
If a person(s) wasn’t particularly concerned with being seen. Such as a heist during business hours. Then setting off the fire alarm system. Either through a fire alarm pull-station or by causing water flow through the sprinkler system. Is an effective way to bypass many alarms and other locked access points. This would be most effective in large buildings with many people. Such as hospitals or large corporate high rises and condo units. Places like these have to be concerned with moving large numbers of people out of the building quickly,so many systems are set up to do just that.
There are many more ways in which life safety systems could be used to access secured areas. I will be covering those listed above and more in greater detail in future posts. As well as methods to counter some of the issues shown. For now take a look around next time you enter a building, and think about ways that life safety might be compromising your security.