Making a door resistant to fire can add important time for people to escape from home fire emergencies
. Two ways of making doors fire resistant exist. The first way is to coat the surface with a protective resin or carbon-based chemical that lowers its ignitability. The second way is to immerse the entire door in a mineral-based solution so tht the entire door is changed in composition.
The former method mentioned of changing the surface properties is accomplished via a resin that is known as a light intumescent. Heavy intumescents and endothermic polymers were used in prior times but are not used so much because when exposed to great heat they tend to give off a lot of smoke that obscures the area of the fire emergency.
Intumescents cannot hold off a fire from a door forever but merely retard flames and increase the time it takes for the door to ignite. They are applied as a thick coat in the manner of paint onto the surface of the door. Exposure to excess moisture and constant heat is discouraged to protect the efficacy of these agents.
The second way of fire proofing is to soak the entire door, as long as it is not yet painted and finished, into a solution. Commonly ammonium or zinc salts are used. After soaking and drying these woods become highly impervious to heat. However, the second method is much more labor intensive than the first.
A very new kind of door is the fiberglass door. Strands of glass are bonded with a resin-like compound in a door-shaped mold. The finished product is a door that's solidly constructed with hardened glass but still contains the flexibility of resin.
The surface of fiberglass could be made to look like traditional wooden doors, but without the disadvantages of warp-age and cracking. Fiberglass doors are also known to be very tough and have warranties that go until 30 years. One downside is that fiberglass doors are hard to fix other than for the most minor of damages.