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Latching requirements on a pair of 90 minute doors

IJHumberson

SAWHORSE
Joined
Oct 30, 2009
Messages
104
Location
Chester, MD, USA
Recently, I've had a few apartment projects that use the horizontal exiting allowances in the codes to the maximum extent allowable. This creates a lot of cross-corridor doors in the building, and we have had to closely examine the doors and the latching of them for the 90 minute fire doors at the horizontal exits. The question that always comes up is, do the doors have to have a latch point at both the top and bottom (either a vertical rods or "poppet" type device) or is there door assemblies out there that have a 90 minute rating with only one latch point? (I haven't been able to find any)

Thank you in advance for your comments!

Ivan.
 
Yes, many of the fire rated vertical rod exit devices can be had as 'Less Bottom Rod (LBR)".

There are some additional requirements if you go with LBR.; your door/hardware supplier can (should be able to, anyway) can fill in the details for your particular application.

The desireable end to this is, no strikes in the floor acting as a trip hazard.

At the end of your comment you say you haven't been able to find any. Are you looking for info, or looking to place an order?
 
@Doorman, I was asked by a Condo Management company because they are repairing/replacing some doors and they asked me if both top & bottom latching was required because their doors had both originally, but some doors have had it removed due to damage... In researching it for them, I couldn't find any doors without bottom latches or poppets that were 90 minute rated... I ended up telling them that it all depends on the door's listing and that a good commercial door company could probably better help them find what they needed... I just posted on here to see if maybe there ARE some doors that are 90 minute listed just the top vertical rod. Thanks for your input!
 
It may not be (probably is not) compliant to install LBR devices on older existing fire rated doors. The LBR feature must have been listed by the door manufacturer as an acceptable latch system at the time of door manufacture.

Most hollow metal and wood door mfgrs and exit manufacturers offer this, and it is (generally) a good way to go.
 
There are definitely fire exit devices available less bottom rod (LBR) for 90-minute doors. They will usually require the auxiliary fire pin (aka "poppet"). As an example, here's a pdf from Algoma showing their wood door capabilities: http://www.algomahardwoods.com/pdf/PosPressA.pdf. In the 90-minute column is a "yes" for SVR/LBR for standard swing pairs and double egress pairs. Some manufacturers may be limited to surface vertical rods (SVR), others may be able to do concealed vertical rods but may require a metal edge channel. It is really dependent on the door manufacturer.

For some exit devices (for example, Von Duprin 99 series), you can retrofit the auxiliary fire pin on existing doors and remove the bottom rods and latches. The retrofit kit from one manufacturer can only be used on that manufacturer's applicable exit devices, so the building owner would have to find out what type of exit devices they have and check with the manufacturer.

In general, if you see a fire rated door with exit devices, and the bottom rods and latches have been removed and there is no evidence of the auxiliary fire pin, that's a red flag. In case anyone is wondering what the auxiliary fire pin looks like, you can see a photo of it on my blog: http://idighardware.com/2009/10/2196/. This happens to be a photo of a pair with an auxiliary fire pin AND bottom rods and latches (DOH!), but you get the idea.
 
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