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Fire Doors

Learn how fire-rated doors protect room and stairwell openings from the spread of fire, smoke, and toxic gases.

About fire doors

A fire door assembly provides passive fire protection within buildings to prevent the spread of fire, smoke, and toxic gases. During a fire, a fire door remains closed to seal off a hallway or stairwell, providing time for escape. Fire-rated doors are certified by testing laboratories, such as Underwriters Laboratory (UL), and can be identified by the laboratory’s certification label on the inside edge or top of the door.

fire door


Both the California Building Code and the California Fire Code address the need for fire-rated door assemblies and the need to properly maintain these assemblies. In common terms, this means that the fire-rated doors, and doors in smoke barriers, are required and cannot be held open by any unapproved means — Fire-rated doors can only be held open if they are part of the building alarm system, so that they automatically release when the building fire alarm system is activated.

Hazards to avoid with fire doors

  • Avoid tying or holding open fire doors with unapproved devices, such as door wedges or blocks. A fire door held open during a fire harms occupants and impedes escape.
  • Avoid tampering with fire door latches. Tape should never be placed over the lock latch, even when closed. Hot gasses can easily build up enough pressure to cause fire doors to open if not latched.

fire after

The pictures above show the effectiveness of a fire door. With the fire-rated door closed, the interior of the room was destroyed (right); while the outside hallway (left) remained clear enough for everyone to escape. Photos courtesy of UC Davis.

Consider the implications of your actions on yourself and co-workers when you manipulate fire-rated doors within your facility. It is the intent of the Fire & Life Safety Division to work with University personnel to provide the highest level of personal safety in the workplace.

For more information, contact EH&S Fire & Life Safety, (858) 534-3659.