NHS fire doors are typically tested to contain fire, smoke, and toxic fumes for a minimum of 30 minutes (FD30 rating). In higher-risk NHS areas, fire doors may be tested and rated to withstand fire for 60 minutes (FD60 rating). The rating indicates the time the door can resist fire and prevent the passage of smoke and toxic fumes under controlled laboratory conditions. However, to maintain this protection in practice, the fire door must be correctly installed, maintained, and not compromised by damage or misuse.