It positive latches!!!!!!!!!!!??????????????Doorman said:The UL and WHI procedures for fire rated doors do not allow a deadlock only on rated doors.This statement is accurate for the manufacturers I represent now, and all those I have represented in the past that I can recall. An inspector may allow it, but somebody (probably) violated a procedure somewhere to get a deadlock only on that door.
Deadlocks: I looked through all my appropriate catalogs, and I cannot find any that come out and say "U.L Listed 3 Hour Latch". A few of them say something like "U.L. Listed Fire Rated Auxiliary Lock".
A deadlock only in a fire rated door would be highly suspect.
and talking about a twenty minute door, also seems a little more sturdy than some of the door latches I have seen on rated doors