A fire door only works closed. The closer is what guarantees that, and it is the component most often defeated, because a door that swings shut hard is annoying and a door that does not quite latch is invisible. Almost every fire door defect found on inspection is a closing defect rather than a door defect.
The requirement
Fire doors are required to be self closing so that they are shut when a fire starts, whoever last walked through. The closer has to overcome the latch, any seals and any air pressure difference, and close the door fully onto the latch from any opening angle, including a few degrees. A door that closes from wide open and stalls near the frame is failing in the position that matters.
The main types
Overhead closers, surface mounted on the door or frame, are the common workhorse and the easiest to adjust and service. Concealed closers, fitted into the door edge or the transom, are chosen where appearance matters and are harder to adjust. Floor springs are used on heavy and double action doors. Free swing closers allow the door to be used as an ordinary door and engage the closing function only when the fire alarm operates, which suits care settings and schools.
Adjustment is the whole job
Most closers have separate adjustments for closing speed, latching action near the frame, and sometimes backcheck at the open end. Closing speed set too slow leaves the door open during a fire; latching action set too weak leaves it resting against the frame. A closer with the correct power size for the door, correctly adjusted, is a door that shuts quietly and completely, which is also the version nobody wedges open.
Power size and accessibility
Closers are rated by power size and a door needs one strong enough for its weight and width. That collides with accessibility, because a heavy closing force is difficult for some people to open. The way out is a correctly sized closer with good adjustment, a free swing or hold open device linked to the alarm, or an automatic door operator, rather than winding a closer down until the door no longer shuts.
Questions people ask about fire rated door closer
Does every fire door need a closer?
Fire doors are required to be self closing so they are shut when a fire starts. Some doors that are permanently locked shut may be treated differently, but that is a decision for the fire risk assessment, not a default.
How do I adjust a fire door closer?
Most have separate valves for closing speed and for latching action near the frame. The test is that the door closes fully onto the latch from a few degrees open, not just from wide open.
What is a free swing closer?
One that lets the door move freely like an ordinary door and engages the closing function when the fire alarm operates or power is lost. It suits care settings and schools where a self closing door is a daily obstacle.