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


Nov 29 2010

Double Cylinder Deadlocks – Residential

Category: Egress,Locks & KeysLori @ 11:44 pm Comments (14)
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I don’t get involved with residential construction very often, but a local locksmith recently asked about the use of double-cylinder deadlocks on single family homes.  His position is that he will not install them, but he was looking for a code reference to back him up.

When I checked the Massachusetts One and Two Family Dwelling Code, I found that double-cylinder deadlocks are prohibited.  I found the same language in the 2009 edition of the International Residential Code (IRC).

Your local code might contain a different requirement, but here’s the paragraph from the 2009 IRC:

R311.2 Egress door. At least one egress door shall be provided for each dwelling unit. The egress door shall be side-hinged, and shall provide a minimum clear width of 32 inches (813 mm) when measured between the face of the door and the stop, with the door open 90 degrees (1.57 rad). The minimum clear height of the door opening shall not be less than 78 inches (1981 mm) in height measured from the top of the threshold to the bottom of the stop. Other doors shall not be required to comply with these minimum dimensions. Egress doors shall be readily openable from inside the dwelling without the use of a key or special knowledge or effort.

Here’s a tragic news report involving double cylinder deadlocks.

14 Responses to “Double Cylinder Deadlocks – Residential”

  1. Charles says:

    I see you did not talk to the police

    Some push the double cylinder locks

    • Lori says:

      Hi Charles –

      No, I didn’t talk to the police (I avoid that if possible), but you bring up a good point – the struggle between security and life safety. Hardware consultants get stuck in the middle all the time when we’re asked to specify/supply hardware that meets the security requirements but isn’t code-compliant. In my opinion, it’s our responsibility to point out these issues to the architect, owner, and the various consultants and to try to come up with a viable solution.

      I spent 2 hours with a building inspector last week going over a very high security building I’m working on. We went through the egress plans and the operation of the hardware, and she confirmed which doors would require a variance. I’m not suggesting that every homeowner should ask for a variance for their double-cylinder lock, just that we need to maintain the balance between life safety and security, and that the code officials (you guys) can be allies to the hardware industry (us) in this endeavor.

      – Lori

  2. Bob Caron says:

    My side door has one and my main entry has cylinder outside x blank plate inside so the house can only have both deadlocks thrown when I’m not in it.

  3. Michael Rebbec says:

    Mr. Caron,

    This is an interesting idea to have a blank plate, but what do you do at night to lock and secure you main entry door? If you are asleep at night, and wanted a deadbolt on your main entry door to be thrown for the additional security it provides a homeowner (which is typically why a deadbolt is on the door in the first place) how would your application work (the only way I can make it work in my head is to then have an integrated deadbolt lock, which, I would think, would defeat the purpose of having the deadbolt with a blank plate).

  4. Roger Papineau says:

    2006 IRC – R311.4.4 Type of lock or latch. All egress doors shall be
    readily openable from the side from which egress is to be
    made without the use of a key or special knowledge or effort.

    2009 IRC – R311.2 Egress door. At least one egress door shall be provided
    for each dwelling unit. The egress door shall be side-hinged,
    and shall provide a minimum clear width of 32 inches (813
    mm) when measured between the face of the door and the stop,
    with the door open 90 degrees (1.57 rad). The minimum clear
    height of the door opening shall not be less than 78 inches
    (1981 mm) in height measured from the top of the threshold to
    the bottom of the stop. Other doors shall not be required to
    comply with these minimum dimensions. Egress doors shall be
    readily openable from inside the dwelling without the use of a
    key or special knowledge or effort.

  5. Jon Payne says:

    I know this is an old post, but I have a question. The paragraphs sited all say “at least one egress door shall be provided”. So, assume a home with multiple doors, one of which has no glass in it or near it. Can the homeowner put a single cylinder lock on it and declare it the official egress door, and then put double cylinder locks on the doors with glass?

  6. Jim says:

    I have double cylinder deadlocks on all of the exterior doors of my home. However, I keep a key inserted on the inside for egress purposes. We only remove them (for security purposes) when we are gone for an extended period of time.

  7. Joe says:

    I know this is an old post, but why use a double cylinder deadbolt at an entry door vs one that has the thumb turn on the inside? Another option could be to use interconnected lock-sets that throw open the dead bolt when the lever is turned on this inside; these usually have the thumb turn as well.

    • Lori says:

      Hi Joe –

      I think the issue is if a door had glass in it, people want the security of a key on the inside because someone could break the glass and reach in to use the thumbturn.

      – Lori

  8. DON SENNE says:

    The point about security and double cylinder deadbolts sounds reasonable, but simply isn’t. I bet anyone on any blog I can open their residential door faster with a well struck blow from my foot than you can open it with your key. Think what you want, feel what you want, that is a fact. Locks keep out those that don’t “really” want in.

    • L.E.O. 89 says:

      a75C”I bet anyone on any blog I can open their residential door faster with a well struck blow from my foot than you can open it with your key.”

      I bet you cannot kick in my basic $550 Home depot steel security door with double cylinder bank fault lock with any two guys kicking it. It would only take pressure to open ANY security door with a single cylinder (thumb turn).

      And yes we can say locks or any security can be defeated — but the fact is the more security ,the more likely the crimes of opportunity burglar will move along to the next opportunity instead of yours.

      Its like having a gun. Will it prevent every crime? No. But they are used to prevent a million or so a year. And contrary to the studies that don’t exclude criminals shooting other crimians, households of non criminal gun owners are aboutr 30% safer than unnamed homes.

      Same with a a large dog. Stop all burlaries? No. Reucde the risk? Yes.

  9. Nelson Dayton says:

    This old post still gets the reads because it is important. Some townships near me won’t allow a home to be sold if it has any double cylinder locks on it. The post from Jon Payne from 2012 asks can you designate 1 door as the mandatory 1 egress door, put a single cylinder deadlock on it, and then put doubles on all the other doors. My guess would be no. We personally won’t install them in homes anymore. But, the potential liability comes from both sides to this argument. If we advise a customer they can’t have double keyed locks, and then they get broken into, we may get sued for giving the wrong advice. Hopefully IRC 2009, R311.2, will be our saving grace.

  10. Don Senne says:

    LEO, you don’t seem to understand the logistics of deadbolt locks. Residentual single cylinder locks and double cylinder locks provide equal “impact resistance”. One is not any better or worse than the other. The only difference is if you were to break the glass window in a door, reach in and open a single cylinder. Burglers don’t do that. It is simiply easier to break out the 5/8″ pine wood jamb with a swift kick. I’ve even seen $550 Home Depot doors fold in the middle when somebody puts a shoulder to it. Again, I can open your home door with my foot faster than you can with your key and I (and burglers everywhere) know this.

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