Access Door - The PFU access door is designed to be installed on fire rated ceilings only. It can easily replace spring loaded models like the PFI. Its door which does not exceed 89 degrees of upward opening, falls back by law of gravity into its locked position as required by fire certification standards. Holding the door open while climbing through it becomes much easier with no springs to deal with. The largest fire rated PFU available is: (24’’ x 36’’ or 864 sq inches).