Commercial Door Closers
A door closer is a mechanical device that closes a door after someone opens it. Door closers are required for fire-rated doors, which need to remain closed, to help prevent the spread of fire and smoke. Door closers have internal springs and hydraulic oil with cylinders and valves that adjust the speed of the door closing and latching. Practically every door in modern commercial, industrial, and institutional buildings is operated by a person passing through and closed by a mechanical door closer which keeps the door closed and under control at all times.