How do we adjust door closers to overcome air pressures?

When a door closes, it attempts to squeeze more air than will fit into the room it’s closing on. Air needs to escape or equalise as the door closes. When air pressures are high, the door needs to close more slowly but with more force. Doors, therefore, need to be adjusted accordingly;

Increase the power & decrease the speed.

Note: small adjustments can make a big difference.

If meeting ADM recommendations, closing power should not be increased more than necessary, as the corresponding force may be taken outside the requirements of BS 8300.