Nailor Model 0722 Ceiling Dampers are for use in spherical programs, in lieu of hinged door type dampers in any UL/ULC flooring/ceiling or roof/ceiling assembly with around a 3 hour fireplace resistance rating exactly where air ducts are permitted. Signals through the AFP or when a pointy increase in temperature exceeding the journey setpoint https://heavy-duty-stainless-stee56677.ltfblog.com/35740136/detailed-notes-on-heavy-duty-stainless-steel-damper-manufacturers