Install Fire-Rated Exterior Doors

05/03/2023

Why do they matter?

In a wildfire, exterior doors experience the same types of exposure as exterior walls. However, exterior doors are usually much thinner and less fire-resistant than exterior walls and can burn much faster. It's critical that the exterior doors remain intact to prevent a fire from entering your home. Consider purchasing and installing exterior doors made from fire-rated materials to better protect your home from the dangers of a wildfire.

What do I need to know?

• Flames and hot gasses can ignite combustible materials in a door and door frame and penetrate openings between the door and frame and between the door and threshold (or floor if there is no threshold).
• Embers can become lodged in openings between the door and frame and between the door and threshold (or floor if there is no threshold). Embers can also be blown through the openings into a home.
• Flames, convective, or radiant heat and airborne firebrands can break glass in a door.

Where do I start?

• Solid exterior doors are usually wood or metal.
• Doors with a solid, noncombustible mineral core are considered fire-rated doors and are rated by Underwriters Laboratories (UL) according to how long they can resist fire (UL Standard 10C).
• UL classifications for interior and exterior fire-rated doors and their frames range from 3-hour to 20‑minute ratings. Exterior fire-rated doors may be rated 1½ hour or 3/4 hour. Door fire rating is intended to equal three-fourths of the fire rating of the surrounding wall. For example, a 1½‑hour rated door is intended to be used in a 2-hour rated wall, and a 3/4-hour rated door is intended to be used in a 1-hour rated wall. However, you may use a door with a higher fire rating.
• Install adjustable weatherstripping on the interior side of the door frame and an automatic door bottom or threshold weatherstripping to block embers and hot gasses penetrating the inside of the home between the door and the frame. The weatherstripping and door bottom should be tested to UL Standard 10C.
• Replace door vision panels that are susceptible to damage from a wildfire with tempered glass with a low-e or proprietary reflective coating, if the door has sufficient fire resistance.
• Replace wooden egress/ingress doors without a solid core. However, egress/ingress doors are often relatively fire-resistant compared to other building components and therefore are not usually a high priority for mitigation.
• Weatherstripping material can melt or burn under very high heat or prolonged exposure to heat, lowering its ability to prevent embers and hot gasses from entering a home.
• Do not shutter doors, as you may need a means of egress in an emergency.

More Resources:

• FEMA P-737, Home Builders’ Guide to Construction in Wildfire Zones.