A latch assembly includes a base having two sidewalls each having a positioning hole. A follower plate includes two sidewalls each having an engagement hole that is aligned with the positioning holes when the latch is in a latching position and that is not aligned with the positioning holes when the latch is in an unlatching position. Two sleeves are mounted between the sidewalls of the follower plate. An end of each sleeve is received in the engagement hole of one of the sidewalls of the follower plate. A stop having a low melting point is received in each sleeve to retain a safety pin in the sleeve. When the stops melt due to heat of a fire while the latch is in the latching position, the safety pins are moved by a spring into the positioning holes of the base to retain the latch in the latching position.