Turnouts. Bunkers. Personal protective ensembles. Regardless of what you call them, the coats, pants and associated garb a firefighter wears at a fire today are sophisticated protective systems as indispensable to modern firefighting as, say, radio communications. But, like radios, that was not always the case.

A century ago, fires were fought in clothes designed primarily to shed water and perhaps provide minimal protection from falling debris. Firefighters wore heavy wool trousers, a cotton or wool shirt, and a heavy wool tunic. Wool was the fabric of choice because of its ability to shield against heat and cold; it also had a modicum of water and flame resistance. A rubberized slicker or coat was worn over the wool uniform.

Knee-high leather boots were the most common form of footwear, but they later would give way to rubber boots that could be pulled up to the hip like waders worn by fisherman. Firefighters usually provided their own standard leather work gloves, and leather helmets completed the outfit.

The first half of the 20th century saw significant advances in firefighting technology, but those advances were more often in the realm of fire suppression applications than in the protection of individual firefighters. And those developments that were directly related to personal protection gear were limited by the materials of the time.

One breakthrough, while not particularly applicable to structural firefighting, was the development of aluminized fabric. The use of aluminum-coated materials to create “proximity” suits could protect wearers by reflecting radiant heat and, as the name implies, allow wearers to approach fires closely. They could not, however, protect the wearer particularly well from flame itself. An account from a 1956 issue of Fire Chief's predecessor, The Volunteer Firefighter, reads in part:

“A suit that enables a man to work in temperatures one-eighth as hot as the sun's surface was demonstrated in New York recently.

“The demonstrator six times entered an industrial furnace heated to 1,200°F, the highest temperature ever entered publicly for more than a few seconds. He stayed two or three minutes each time as if on a repair or rescue mission.

“The demonstration — sponsored by Minnesota Mining and Manufacturing Co. — was held to show the heat-protective qualities of fabrics coated with a thin layer of aluminum, a process developed by 3M. The aluminum-coated fabric reflects radiant heat instead of insulating against it. This permits less bulky insulation, it was explained, so that a man can move and work at temperatures higher than ever before to repair, investigate, inspect, rescue or extinguish.

“To demonstrate the intense heat from which he was protected, an engineer wearing the aluminum-coated suit walked into the 1,200-degree oven carrying an armload of wood which burst into flames while he held them. He returned with a … manikin wearing a fireman's rubber fire-fighting coat and another wearing ordinary street clothes, both of which burned while he was unaffected.”

An industrial oven, however, isn't a burning structure. Reflective material can be of benefit at fire where there's intense radiant heat, such as with flammable-liquid fires, but it does not help protect against heat transfer by convection, as occurs in smoky interior fires. While the demonstration was extraordinary for the time, the use of protective clothing constructed of aluminized fabric by firefighters was limited to relatively narrow sets of circumstances.

Even as recently as the 1960s, despite all the advances in other areas, firefighters' protective clothing was very much the same as it had been in the decades prior. The fabrics used in construction often weren't even flame-resistant. In fact, in the early 1970s it was estimated by some that as much as 75% of the turnout gear in use would not even pass the standards for flammability in place for children's sleepwear.

A number of organizations and groups, however, were calling for more attention be paid to the issue of firefighter safety and protection. That outcry, coupled with new materials becoming available for use in the construction of PPE, would begin a radical change in firefighter protective gear that continues today.

Materials matter

A flame- and heat-resistant material developed by DuPont — called a meta-aramid in scientific circles, but better known to most by its brand name Nomex — would have a profound influence on protective gear for firefighters. Introduced to the marketplace in the late 1960s, Nomex still had to prove its worth. Critics felt the fact that the material did not absorb water and that its relatively thin layers somehow diminished its ability to protect wearers. But Nomex found early success in aviation applications, and the military began specifying Nomex for flight suits and coveralls. Eventually the fire service, too, saw its value. Today, it, in combination with other recently developed materials, has become an integral aspect of fire protection equipment.

Another material that would find wide-spread application in protective fire equipment is a thin, porous fluoropolymer membrane with a urethane coating — a material otherwise known as Gore-Tex. This material has about nine billion pores per square inch, each of which is approximately 20,000 times smaller than a water droplet, making it impenetrable to liquid water while still allowing the smaller-sized water vapor to pass through. The result is a material that is breathable yet waterproof and windproof. This is in contrast to traditional rubber-coated turnout coats, for example, which lack breathability and therefore promote a build-up of humidity in the air inside the coat, preventing sweat from evaporating effectively.

Remembering the '70s

Capt. James Turner, an equipment development officer with the Los Angeles County Fire Department, speaking at the Conference on Protection for Firefighters held at the Illinois Institute for Technology in 1976, described the personal protective gear of the day as “… turnout coats and pants, or bunker clothing, as they are referred to in the eastern part of the nation. As used in the colder climates, bunker clothing generally will have the vapor barrier or rubber as the outer shell, to allow the water to run off and prevent ice build-up during sub-freezing temperatures. They will then have an inner liner to provide padding and warmth. Normally, the bunker coat will be knee-length and the man will be wearing I-length hip boots under the coat.

“In the western part of the nation, the turnout coat and pants are used. The turnout coat normally consists of a heavy canvas duck, or Nomex outer shell with a removable inner liner consisting of a rubber vapor barrier and cotton flannel liner next to the body. These coats normally reach down to mid-thigh and the uniform pants are used to provide leg protetion.

“Turnout pants are normally only used at night, after personnel have gone to bed, and provide a rapid means of donning both the pants and 18-inch — high rubber boots; they are also worn during inclement weather. The turnout pants are of the same materials and construction as the coat.”

Asst. Fire Chief James Petersen of the Sugar Grove (Ill.) Fire Department, speaking at the same conference, summarized the issue of injury and death among firefighters relative to personal protective equipment as a two-fold problem. The first aspect, he said, was the result of a lack of use of the personal protective equipment available to firefighters and the second was “certain inherent deficiencies” in that equipment. The problem of deficiencies in equipment could further be divided, according to Petersen, into a lack of awareness of the deficiencies of the equipment, as well as a lack of information of the availability of improved gear.

Petersen's remarks point up the issues of the time. “Turnout coats [are a] highly controversial area,” he said. “Shell fabrics are available in canvas, rubber, Nomex and Kynol, just to mention a few. The coat is, in essence, a three-part garment. It consists of a shell fabric, a vapor coat and a thermal barrier. For example, in a rubber coat, the shell fabric and vapor barrier are combined. On the other hand, Nomex is not a waterproof shell fabric, and the vapor barrier is frequently bonded to the thermal liner. Unfortunately, the thermal barrier is often referred to erroneously as the winter liner. It should be understood that the heavy inner liner, often detachable, is not just for purposes of warmth, but is the only part of the coat [that] provides protection from heat.

“One of the problems not yet satisfactorily solved results from the entrapment of the wearer's body heat; however, this difficulty can frequently be minimized by the proper use, deployment and rotation of manpower. The popular untreated canvas shell fabric has been clearly demonstrated by experience and testing to be readily flammable.… Liners of wool and nylon also have proved to be extremely flammable.

“Fortunately, however, there are now available both shell and liner materials which are flame resistant and which will not support ignition. While it is recognized that there are situations encountered by [firefighters] in which no amount of available protection will prove sufficient, … a coat composed of flame-retardant material which will not support combustion and provide a reasonable measure of thermal protection will give the wearer an added margin of escape time. In our concern for protection from burn, impact injuries should not be overlooked. A properly lined and padded coat will contribute significantly to the reduction of impact injuries.”

Ronald K. Melott, senior fire service specialist with the NFPA's Public Protection Division, addressed the conference from the perspective of the newly enacted NFPA 1971, Protective Clothing for Structural Fire Fighting. “[T]he NFPA Sectional Committee on Protective Equipment for Firefighters has just completed the development of the first standard on protective clothing for structural fire fighting (ordinary turn outs). This standard was officially adopted in November 1975 and was hailed as a landmark by the fire service, manufacturers and other interested parties since it now establishes minimum performance requirements for the protective clothing that the fire fighter ordinarily wears in fighting fires.

“One of the first things this committee had to realize in the development of this standard is that it would be impossible to protect the fire fighter against all hazards that he might encounter while in the performance of his duties. Therefore, reasonable judgments had to be made as to what is the normal safe environment in which the fire fighter is expected to operate and what can be provided in the areas of thermal protection, flame resistance, water repellency and comfort within reasonable economic limits and manufacturing technology capabilities. It is understood by the committee that this standard is not going to be readily accepted by all members of the fire service because it is going to mean an expenditure of money in order to update existing equipment. It is not going to allow them the complete freedom of removing the liners from turnout clothing, and in many cases it is not going to allow the fire department a wide choice of style. However, this garment will materially improve the fire fighter's ability to survive while performing normal fire fighting functions.

“This standard is not intended to be restrictive relative to materials or garment structure, but the basic requirement of 500°F for five minutes in a laboratory oven without charring, melting and dripping or shrinking over 10% is intended to be minimum performance criteria for the material used in the outer shell construction. This performance criteria, however, is not intended to be the environment in which the fire fighter will be completely and totally protected, but is set forth as minimum comparison criteria for materials which will afford the fire fighter reasonable safety and protection from the hazards of fire fighting.”

Development of NFPA 1971

The initial work toward what would become NFPA 1971 was begun by the NFPA's Sectional Committee on Protective Equipment for Fire Fighters that was part of the Committee on Fire Department Equipment. In 1973, the committee released a tentative standard (NFPA 19A-T), then continued its work in cooperation with the Program for Fire Services Technology of the National Bureau of Standards. That work would result in the standards presented and adopted at the NFPA's fall meeting of 1975. New editions of the standard have been issued roughly every five years since then.

NFPA 1971 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. It also specified 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 were developed that would require gloves be constructed to be able to withstand flame, heat, vapor, liquids and sharp objects, and footwear to be resistant to puncture, flame, heat, abrasion and electrical current.

The 1981 edition of NFPA 1971 was a complete rework of the 1975 edition and made the document more usable by both the fire service and protective clothing manufactures. The 1986 edition was another complete revision of the document to include more performance requirements and fewer specifications, and contained separate performance and testing chapters.

Among the steps forward in the 1980s was a specification that turnouts be made with an outer shell material with a fire resistance level to 1,200°F before the material begins to break down. Another requirement was that the construction of gear allow moisture to be released from inside.

The 1991 edition of NFPA 1971 addressed third-party certification, labeling and listing for protective clothing. It also incorporated a new chapter addressing interface items, specifically the protective hoods and protective wristlets. In addition, appendix material addressed the subject of cleaning garments and evaluating how materials can affect heat stress. The 1997 edition combined four former standards on structural firefighting protective clothing: NFPA 1971, Protective Clothing for Structural Fire Fighting; NFPA 1972, Helmets for Structural Fire Fighting; NFPA 1973, Gloves for Structural Fire Fighting; and NFPA 1974, Protective Footwear for Structural Fire Fighting. The new, single document would be entitled NFPA 1971, Protective Ensemble for Structural Fire Fighting.

The 2000 (sixth and current) edition of NFPA 1971 represented a complete revision to the 1997 edition, adding new requirements for evaporative heat transfer through garments through a total heat loss test, for evaluating thermal insulation in areas of garments that are most likely to be compressed, for evaluating hand dexterity with gloves, and for evaluating the durability of barrier materials. This edition of NFPA 1971 will be replaced by a seventh edition later this year. Among the design changes anticipated are an increase in minimum boot height, a decrease in minimum collar height, incorporation of a drag rescue device, and allowance of aramind hook-and-loop fasteners. Increases in certain minimum performance standards are also expected.

Another aspect of protective gear, not a matter of protection from heat but equally important to firefighter safety, is visibility. This, too, is addressed in NFPA 1971, with garments being required to have fluorescent and retroreflective trim permanently attached to their outer shells. The standard does not specify the color of the outer shell itself, however — a point with which many take issue.

As William Clark says in his classic text Firefighting Principles & Practices, “Many firefighters have been hurt and several killed because they weren't seen. Some were knocked off rooftops or ladders; some were struck by automobiles. In darkness, a firefighter dressed in black is almost invisible. The only reason I can see for firefighters wearing black is the tyranny of tradition in the fire service. Years ago, all waterproof coats were made of rubber, and rubber was available in black only. Nowadays, all kinds of material and colors are available for firefighter's garments, yet we find that some men are still clad in black. Black is not only the least visible color in the dark, but it also absorbs the most radiant heat.”

Development continues

As the fire service assumes increasing responsibility for first response to emergencies other than fire, the need for gear that protects the wearer in a broader range of hostile environments increases, as well. The concerns for chemical, biological, radiological and nuclear risk is forcing gear designer and manufacturers to prepare for standards of protection that will continue to raise the bar relative to performance. An option governing minimum CBRN protection is expected in the new version of NFPA 1971 to be issued yet this year. In addition, several commercial initiatives are already under way to enhance the CBRN protection of structural turnout gear.

A firefighter's PPE today — just in terms of coat, trousers, gloves and hoods — certainly provides an extraordinary level of protection compared to the firefighters of 50 years ago. But that very protection requires a caution in itself. As Clark pointed out 15 years ago, “Firefighters should be taught that their protective clothing is not fireproof. The outer shell of the garment is required to give only 15 seconds' protection against flashover temperatures, just enough for quick retreat to a known and readily available exit. They should also learn that the heat-resistant properties of the garment are meant to allow them to escape from a dangerous situation, not to march into one.

“…[P]rotective clothing and equipment allow firefighters to get into places they should stay out of, and the senses that nature gave them to detect danger are dulled by their equipment. They can't see, they can't smell, they can't feel external temperature changes, and their hearing is impaired. These are hardly advantages to persons in a hazardous environment — and so equipped, they can venture unsuspectingly into situations of high hazard.”