Gregory Harrington

#101Wednesdays: Electrically-controlled egress doors (and fake history)

Blog Post created by Gregory Harrington Employee on Feb 8, 2017

A few weeks ago, in my #101Wednesdays post about escape rooms, I talked about the importance of not locking occupants in buildings. Quite simply, when people are locked in buildings and a fire occurs, they have a tendency to die. So the Life Safety Code goes to great lengths to ensure occupants have the ability to open doors and get out of the building when they need to. (There are, of course, exceptions for occupancies like detention and correctional and health care, where occupants are secured in the building for their safety and ours.) The Code does, however, recognize the need to secure doors in the closed position, and that’s fine as long as people can easily get out. Thus we have the requirements for door locks and latches in 7.2.1.5 of NFPA 101 (you can review them online, for free

). In summary, occupants must be able to open an egress door with not more than one simple operation, without the use of keys, tools, special knowledge or effort, and under all lighting conditions, including no light.

 

Traditionally, doors have been secured closed mechanically; go up to the door, operate the releasing mechanism which mechanically retracts the latch, and the door opens. These days, thanks to Alexander Hamilton’s invention of electricity* (that was for my daughter), doors can be secured closed by electronic means, using electromagnets and electronic control hardware. Instead of mechanically releasing a latch, the occupant operates a releasing switch, which sends a signal to the control hardware, which in turn drops the power to the electromagnet and allows the door to open. From the occupant’s perspective, this door operates the same as a door with mechanical latching hardware.  Mechanical latches are pretty simple – not a lot of opportunity for failure. Electronic systems are more complicated and have more potential failure modes, so the Code needs to address them.

 

The requirements for electrically controlled egress doors are located in 7.2.1.5.6 of NFPA 101. Six criteria are specified:

(1) The hardware for occupant release of the lock must be affixed to the door leaf.

(2) The hardware must have an obvious method of operation that is readily operated in the direction of egress.

(3) The hardware must be capable of being operated with one hand in the direction of egress.

(4) Operation of the hardware must interrupt the power supply directly to the electric lock and unlock the door assembly in the direction of egress.

(5) Loss of power to the listed releasing hardware must automatically unlock the door assembly in the direction of egress.

(6) Hardware for new installations must be listed in accordance with ANSI/UL 294, Standard for Access Control System Units.

Where these criteria are met, the door should operate just like any other egress door, and it is not considered a special locking arrangement. Special locking arrangements are addressed in 7.2.1.6; I’ll discuss those in a future post.

 

Just yesterday, I had an advisory service call about electronic locks. I knew immediately what the caller was going to say – I hear it all the time. “I have a door that’s locked with an electromagnet. To get into the facility, you swipe a key-card and the door unlocks.” No problem, NFPA 101 doesn’t care about occupants’ ability to get into the building - only their ability to get out. Caller: “It’s also tied into the fire alarm system, so the magnet will release when there’s a fire.” To which I replied, “I see. And how does someone get out under normal conditions?” Caller: “Oh, they have to swipe a key-card.” Me: “I see. What if they don’t have their key-card?” Caller: “Well, it will unlock if the fire alarm goes off.” Me: “What if the fire alarm doesn’t go off for some reason?” Caller: “Oh, there’s a push-to-exit button on the wall by the door.” President Trump: “WRONG!” While this might sound like a compliant arrangement, it’s not, because to open the door, an occupant would need to know about the push-to-exit button, which might not be visible in an emergency if the lights go out (special knowledge). The door has to be able to be opened by releasing hardware attached to the door leaf, which is typical of mechanically latched doors, and is a requirement for electrically controlled egress doors.

 

Another question we sometimes get relates to standby power. If the electronic locking system is provided with standby or emergency power, are the doors required to unlock if the building loses power? The answer is no, as long as the system functions like it’s supposed to when powered by an alternate source. If the electronic system loses primary power and there’s no backup, the locks are required to fail-safe – that is, unlock.

 

The Life Safety Code got its start as the Building Exits Code; I can’t overemphasize the need to provide building occupants with free egress. If the provisions I’ve described here are followed, security can be provided without sacrificing life safety. I hope you’ll return for a future installment of #101Wednesdays. Until then, stay safe!

 

*IMPORTANT HISTORICAL ACCURACY DISCLAIMER: For all you 8th graders doing your science fair projects on egress doors, Alexander Hamilton didn’t invent electricity. As we all know, Hamilton was a hip-hop artist who founded the American financial system and died in 1804, years before the invention of electricity by Al Gore, who also invented the Internet. #ItsMyBlogICanHaveFunIfIWant

 

Got an idea for a topic for a future #101Wednesdays? Post it in the comments below – I’d love to hear your suggestions!

 

Did you know NFPA 101 is available to review online for free? Head over to www.nfpa.org/101 and click on “Free access to the 2015 edition of NFPA 101.”

 

Follow me on Twitter: @NFPAGregH

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