While most fire doors are for interior use, some of them may be installed with partial exposure to outdoor environment. Others may be susceptible to moisture and water damage. Since most of overhead door closer arms are made of metal and floor springs may trap water inside, rust is a universal threat for door closing device. Rust also ultimately lead to door closer repairs.
Not only do they make the structures brittle, it may inhibit smooth operation, and worse yet, may cause the door closers to be completely stuck. In the event of emergency, that’s a big risk to undertake.