Underwriters Laboratories

(UL - cUL)Yale 8800 series mortise locks have been listed by Underwriters Laboratories Inc. for use on fire doors having a rating up to and including 3 hours and for use on 20 minute wood doors. This pertains to single swing doors not exceeding 4 feet in width and 8 feet in height and in doors mounted in pairs not exceeding 8 feet in either direction (unless otherwise noted in the individual listings.)

In general, single-point mortise locks or latches with 3/4" minimum latch throw are intended for the active leaf of doors mounted in pairs, with the inactive leaf provided with top and bottom flush or surface bolts of the manual, automatic, or self-latching type. The door Classification Marking specifies the minimum latch throw required for the individual door.

Yale 8800 series mortise locks with 3/4" throw latchbolts may also be used on single swing doors rated 1-1/2 hours or less, up to 4 feet in width and 9 feet in height. This is in addition to the rating mentioned above. All Yale 8800 Series Mortise Locks with Lever Handle Trim are UL listed for fire door applications. Underwriters Laboratories does not list locks with rabbeted fronts, locks with deadbolt only, or locks with hold-back feature on the latchbolt.