A door system for a boiler penthouse or other high temperature industrial environment is disclosed. A sufficiently large entranceway for both workmen and large equipment is provided by the door system. The access door has the capability for quick gas-tight sealing during closing. A hinged metal door...http://www.google.fr/patents/US4685586?utm_source=gb-gplus-shareBrevet US4685586 - Boiler penthouse access door
