Access Door - The PFI access door is insulated with 2” thick mineral wool and can be used on fire rated walls and ceilings. It comes with a 1” flange for an easy flush installation on any type of surface. As per UL and NFPA standards, once the installation is complete and the provided springs are hooked to the back of the panel, the door will be self closing and self locking. The largest fire rated PFI doors available for vertical and horizontal installations with temperature rise are respectively: (48’’ x 48’’) and (24’’ x 36’’ or 864 sq inches)