Posted By Martin R. Bessant This message is posted on behalf of Gary Cutter who is unable to post messages at present. "Hi Paul, The answer to your question is not so straight forward as it would seem. Fire doors are provided as means of escape in case of fire and as structural fire protection. It is perhaps incorrect to simply call a door a fire door because its fire resistance ability relies on the complete doorset. This will include frame and ironmongery all being compatable and able to function together. Generally, all doors have some fire spread delayng properties, but doors must have standards for test periods of 20, 30, or 60 minutes to be considered fire doors. With fire resistance two properties are sought, that is integrity and insulation. Integrity is maintained if the door is prevented from deflecting or warping. This is achieved by good fit and a secondary restraint from the clamping/expanding action of the seals. Normally a fire officer would require doorsets to achieve both features. However, if the door has been required under the Building Regs. (which I suspect it has) then the only requirement would have ben integrity. Now to your specific question. If the plug is blue with a white surround and has no intumescent seal fitted then it will offer 20 minutes integrity in the event of fire (assuming that the compete doorsey is good). If the door was fitted with intumescent seal in either the door edge or frame then, with the same assumption could offer 30 minutes protection. Hope this is what you were looking for. Regards, Gary Cutter, Chair - Fire Risk Management Specialist Group.