What is Fire Resistance?
A fire-rated door — or fire-resistant door — is specially constructed to slow or prevent the spread of fire and smoke, according to Ken Canziani, Senior Fire Investigator at EFI Global in Sacramento, CA.“A fire-rated door is a very heavy door made of materials like metal or gypsum,” Canziani explains. “The term ‘fire-rated’ means that the door, when installed properly, is not supposed to combust during a certain time frame in the average fire.” While time ratings vary, he says standard ratings include 20- to 90-minute doors.
How can a Fire Resistant Door help during a fire?
Fire-rated doors can help slow or prevent the spread of fire and smoke, but Canziani warns that they are not designed to be completely fireproof. “These doors are made of combustible materials and will eventually burn through in a fire. However, they will resist the penetration of heat and flames to slow the fire for a specified time period.”
Fire rated doors are subjected to endurance testing where the specimen is exposed to extreme heat of up to 1925 degrees F for the maximum 180 minute rating. If the door remains in the frame with no through openings and limits flames, it is certified with an endurance rating of either 20/45/60/90/180 minutes.
After the fire endurance test, the test specimen is subjected to the hose stream test, where a fire hose delivers water at 30 psi from 20 feet away. Note that building codes throughout the US typically stipulate that 20 minute doors are exempt from the hose stream test.