Turnout gear, or the protective clothing worn by fire fighters, has come a long way since the last century. In that era, fire fighters wore Civil War-style uniforms that featured heavy wool trousers, a cotton or wool shirt (usually red), and a heavy wool tunic. Wool was the obvious choice, because of its ability to shield against heat and cold, and because of its mild water and flame resistance. Rubber slickers were sometimes worn over the wool uniforms. Fire fighters brought their own gloves to the job, usually standard leather workingmen's gloves. Knee-high leather boots worn in the early years eventually gave way to rubber boots, some of which could be extended to the hips like modern waders (called "three-quarter boots").
Turnout gear took a great leap forward after World War II, when various organizations, foremost among them the National Fire Protection Association (NFPA), began issuing standards. The NFPA 1971 Standard on Protective Clothing for Structural Fire Fighting, for instance, called for an outer layer of flame-resistant fabric that would not be destroyed through charring, separating, or melting when exposed to 500°F for a five-minute period; a second layer to prevent moisture from penetrating through to the wearer; and a third layer to provide thermal insulation from radiant, conducted, and convective heat. Similar standards required gloves that could withstand flame, heat, vapor, liquids, and sharp objects, and footwear resistant to puncture, flame, heat, abrasion, and electrical current.
In the 1980s, fire fighters began wearing turnouts made of three advanced materials: an outer shell material that raised the fire resistance level to about 1,200°F before the material began to break down; a layer that allowed the fire fighter to release moisture from inside the gear; and a fire-resistant synthetic material. Ideally, the latter will last about seven seconds in a flashover situation (when all combustible materials, including walls and floors, suddenly ignite) before catching on fire, which is usually enough time for someone to bail out of room. Further, it is self-extinguishing, meaning once out of contact with a fire, it will not continue to burn. These materials have become the standard for virtually all American fire departments.
Modern turnout gear has become so effective in insulating the fire fighter from heat that new equipment is now being introduced that has an internal alarm to alert him or her when the external temperature exceeds a set limit. These next-generation turnouts consist of six silicone-encapsulated heat sensors located at the shoulder, back, and chest of the turnout coat, just under the outer shell.