Access Control: Where Do You Use Mantraps?

Brian Rhodes
Jul 11, 2013
IPVMU Certified

I am gathering materials, information, and insights on a post about mantraps. Wiki describes them as:

"In modern physical security protocols, a man trap refers to a small space having two sets of interlocking doors, such that the first set of doors must close before the second set opens.[4] They are also known as air locks in the security industry."

[UPDATE: Here is our mantraps tutorial.]

A few questions for you:

  • Which is the largest (number of doors) mantrap application you've seen or worked on? 2 doors? 4 doors? 100 doors?
  • Can mantrapped doors be emergency egress doors? (Leaving the secured side.)
  • What sort of code oversight dictated design? Sources?
  • Did you use special 'mantrap controllers', or did you configure an electronic access control platform to provide the function?

I appreciate your feedback in advance!

Matt Ion
Jul 11, 2013

Well, I've only had to work on two different types... one was set up on the exit from a liquor store, and both maglocks were simply engaged from the cashier's desk switch: if someone was making a run for it, the cashier would have to time the switch activation for just after the runner opened the first door; then both would lock and he'd be trapped inside.

The other style was actually on some gas station pay windows, where the inner door had to be closed and locked before the outer door would open. In that case, it was accomplished using small maglocks with internal closure sensors going to relays: when both doors were closed, both would be unlocked. If either were opened, the other would lock immediately.

Other than that, I've seen it on a couple seniors' homes, where the sliding doors were on motion sensors for entry, and a keypad for exit (to prevent residents with conditions like dementia or Alzheimers from just wandering out), but either door would only open when the other was closed. No idea how it was all controlled though.

John Grocke
Jul 11, 2013

I have used them in courthouses, jails, police stations, clean rooms, and medical research facilities.

We use Genetec most of the time and you can configure up to a 4-door mantrap in the software without any special controllers. Other times, I used the older Dortronic controller or programmed my own controller using an IDEC Smart Relay, when special timing or functionality was required.

Aside from a fire alarm override, there weren't any code issues.

In jails, mantraps are commonly referred to as sallyports.

Jim Elder
Aug 03, 2013
IPVMU Certified

Man traps are solutions to address two very specific needs: As a security portal, to reduce or eliminate tailgating or escape; and for airlock reasons such as BSL4 labs and clean rooms. Some can be very complex and can be very difficult to design, involving a multitude of design disciplines (A & E types) special sensor arrays and links to other systems using programmable controllers (check out this one from Doortronics ) and Boolean logic. A staffed sallyport application is pretty simple and can be done with relays and push buttons.

If it is unstaffed however, a whole new dynamic is involved, particularly if tailgating or piggybacking prevention is your goal. In these cases, special sensors such as stereoscopic cameras or very specialized PIR “presence detectors” must be involved to detect the presence of the tailgater and it is here where you should consider a manufactured mantrap (here’s is one from an Italian company). If tailgating or piggybacking is your only worry, than consider a revolver or full height turnstiles. I have designed many, and these entry portals can be extremely expensive. A revolving door with tailgating and piggybacking options can easily cost $50-100K. But if you can eliminate a full time position, the door can pay for itself in one year.

Answering your questions, Hope this helps.

  1. How many: my experience is 5—but only one was a true mantrap, the rest were very expensive revolvers.
  2. Emergency egress doors? Yes they can be. If it’s a means of egress, you cannot use interlocks as the only way out, (even if you do connect it to the fire alarm) unless they have breakaway panels or you have a special application (i.e. a jail). There is also the issue of rated partitions, fire alarm release or having a standard swing door with delayed egress or alarmed exit devices, next to the portal.
  3. Code oversight? Not sure what you mean here, but the UBC is typically what most newer local codes are based upon. Clearly, you need to make sure you are in sync with local codes on the matter. In most locations you can install portals when there is an egress door next to the interlock (see 2 above). You should know the type of occupancy (i.e. education, business, healthcare, etc) and the design egress requirements for the particular door (i.e. exit width). Your best bet is to have a license architect involved and provide a submittal for approval to the AHJ.
  4. Mantrap controllers or EAS system? Actually, I have used both. I would suggest that you use a controller that is tested for your application and not the access system. You can then use the output of the reader controller to provide an input to the interlock controller.
Michael Budalich
Aug 04, 2013

I am surprised there has been no mention of casino counting rooms in this discussion. I thought that was a common application for mantraps.

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