Printed from the blog of Lori Greene, AHC/CDC, CCPR, FDAI
Allegion
Email: lori_greene@allegion.com, Blog: www.idighardware.com or www.ihatehardware.com


Jun 01 2012

Decoded: Electric Strikes on Fire Doors (Updated July 2017)

Category: DHI,Electrified Hardware,Fire DoorsLori @ 11:53 am Comments (8)
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This post was printed in the June 2012 issue of Doors & Hardware

[Click here to download the reprint of this article.  Note that the reprint does not include the 2017 updates.]

Someone recently asked me why, after going to architectural school, I decided to become a hardware consultant instead of an architect.  Right around graduation, I decided that I couldn’t become an architect because the process was way too subjective for me.  I like right/wrong, black/white.  I like math…you get an answer and it’s right or wrong.

I think that has a lot to do with my interest in the codes.  When someone asks me a code question I can usually go right to the applicable code book and translate what is written there, and there’s always the commentary or handbook to give a little extra insight.  They’re not always black and white but we can work toward an understanding of the intent even if the language isn’t perfect.  The AHJ can sometimes be a bit of a wild card, but they are usually open to having a discussion and most of the time we end up on the same page.

I hate to respond to a question by saying, “Well, that’s a grey area…”  In those cases I like to dig around until I can provide a solid interpretation with proof to go along with it.  My interpretation isn’t official, but at least it’s something to refer to and discuss.

In my opinion, the issue of electric strikes on fire doors is NOT a grey area, but in researching the requirement for someone who needed some evidence, I discovered that the codes are not very specific about it.  You need to put all of the pieces together to provide something more than “because I said so.”

The question has come up several times in relation to electric strikes on stair doors.  According to current codes, most stair doors have to allow reentry back into the building during a fire, therefore, a fail safe product must be used.  With a fail safe electric strike, cutting the power means that the spring-loaded keeper is the only thing holding the door closed, and that is not enough to be considered positively latched.  The pressure from a fire can push the latchbolt right through the keeper and the open door will allow smoke, heat, and gases to compromise the stairwell.  I have had several people tell me that the pressure in the stairwell will keep the door latched, but I have never seen a basis for that belief in the codes.

If a door is fire-rated, an electric strike has to be fail secure to provide positive latching.  And a fail secure electric strike will not provide for stairwell reentry.  So in my opinion, electric strikes should not be used on stair doors, but the fail safe / fail secure question is not specifically addressed in the code language.  You have to look at all the evidence and come to a conclusion.

The International Building Code clearly states that stair doors must “be capable of being unlocked simultaneously without unlatching,” and the IBC Commentary further clarifies the latching requirement by stating, The unlocking of the door must not negate the latching feature, which is essential to the operation of the door as a fire door.  See below for the code excerpt.

NFPA 80 says:  6.4.4.11* Electric strikes shall be permitted to be used in lieu of conventional strikes in single swinging doors and pairs of doors where provided for in the published listings.

I looked at the UL Building Materials Directory to see if the “published listings” would help clear it up, but I didn’t see anything specific regarding fail safe / fail secure (Ref 1, Ref 2).  I found a couple of references in a manufacturer’s catalog:

Fail Safe — FS electric strikes require power to be applied to lock the strike lip. On loss of power, the strike is unlocked. Building codes prohibit the use of fail-safe strikes on labeled openings.

UL listed Burglary Resistant CVXY and Electric Strike for fire doors or frames GXAY (fail secure only).

And these Von Duprin fail secure strikes have UL labels for fire and burglary, while the fail safe strikes only have a UL label for burglary:

 

If you connect the dots, it seems obvious that a fail safe electric strike won’t meet the latching requirements, and a fail secure strike won’t meet the reentry requirements, so electric strikes should not be used on stairwell doors.  On other fire-rated doors which are not required to unlock upon fire alarm or a signal from the fire command station, a fail secure electric strike can be used.

Here’s the text from the IBC and Commentary:

403.5.3 Stairway door operation. Stairway doors other than the exit discharge doors shall be permitted to be locked from the stairway side. Stairway doors that are locked from the stairway side shall be capable of being unlocked simultaneously without unlatching upon a signal from the fire command center.

Commentary:  Section 1010.1.9.11 (1008.1.9.10 in older editions) requires that all egress doors for interior stairways be readily openable from both sides. It is often desirable to control movement of people within a building and to provide additional security from external threats. This section permits locking of stairway doors from the stair side when all doors are capable of being simultaneously unlocked. Since high-rise buildings are difficult to evacuate and people are often relocated to another floor level during an emergency, access from the stairway to a floor could be essential in a fire or other emergency. Therefore, all stairway doors that are to be locked from the stairway side must have the capability of being unlocked on a signal from the fire command center. The unlocking of the door must not negate the latching feature, which is essential to the operation of the door as a fire door.

This post was originally created on March 2, 2012, was printed in the June 2012 issue of Doors & Hardware magazine, and was updated in July of 2017.

8 Responses to “Decoded: Electric Strikes on Fire Doors (Updated July 2017)”

  1. Joe says:

    My first response to this post is, “Why would anybody argue this?” 🙂 You must have a lot of patience.

  2. Jerry says:

    Thank you!

  3. Hal Kelton says:

    Hi Lori,

    Some confusion, or should I say the demand for “electric strikes” on stairwell doors might be coming from a small misunderstanding of correct terminology. There are a couple of products out there specifically designed for this exact application. For example, the Architectural Control Systems Inc. “Gemini Locking System” is a UL listed locking system that combines a special mortise lock modification along with a special strike, UL tested and listed together, allowing a fail safe electrical operation while maintaining the proper latching requirements for labeled stairwell doors. The strike is referred to as an “operator”, even though it looks a lot like the more common electric strikes used today for access control applications. The Gemini Operator works in unison with the mortise lockset. All of the power is run to the door frame and into the operator, no power transfers or raceways through the door to the mortise lock are required. The voltage capabilities for the frame mounted operator are designed to integrate well with the life safety systems already in place in any building occupancy, they range from 115AC, 24Vac/dc, 12Vac/dc, or pneumatic operation. Here’s a link to a PDF diagram and description of the system I just explained: http://acsi-inc.com/cms/uploaded/docs/8500%20GEMINI.pdf

    I hope this helps,

    Hal

  4. Bob Caron says:

    The evidence seems obvious to me too. According to the code, the door has to be latched so it doesn’t matter if it’s true that pressure will keep a door shut or not. It still must be latched. No gray area there.

  5. Justin Ritter says:

    So just use a fail safe electrified lock (or exit device) – simple…except in the case of retrofit applications, or the “fear” of using something besides an electric strike (God forbid).

  6. Gary G says:

    Why not just use an electric lock such as the Schlage ND80PDEL. This unlocks when power is cut off. Unless you are using it with an auto operator, which I assume you would not be doing in a stairwell door.

  7. Bruce M says:

    Very informative – Thanks

  8. David says:

    Electric mortise are the fad where I am at. Both rated fire doors and non rated fire doors.

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