As the fire alarm sounds, firefighters are acutely aware of the vital protection provided by the turnout gear they put on before heading out on the call. In fact, turnout gear is one of the most important tools that firefighters have to protect themselves while in the line of duty.
A firefighter’s turnout gear must be tough and durable while maintaining comfort and breathability to minimize fatigue and heat stress for those wearing it. Firefighters may be asked to respond to any number of various scenarios in a given day; their turnout gear must allow them the flexibility to respond to a vehicle accident, ventilate a roof, or fight a three-alarm blaze.
Although many people can visualize what a turnout coat looks like, the inner workings of turnout gear are less known. As the first, and most crucial, point of protection for firefighters, turnout gear should provide them with adequate protection against burn injuries over a wide range of conditions while minimizing heat stress.
Turnout gear is comprised of three distinct layers: the thermal liner, the moisture barrier and the outer shell. Each serves specific multiple functions.
The Thermal Liner
The thermal liner is the most critical component in turnout gear because it has the biggest impact on thermal protection and heat stress reduction. Together with the moisture barrier, the two layers account for up to 75 percent of the thermal protective performance of a turnout garment. Thermal liners trap air in or between layers of nonwoven material that is quilted to a face cloth material. More so than the other layers, the material makeup of the thermal liner is critical to the comfort and safety of firefighters.
The ideal face cloth offers wickability and smoothness, improving garment mobility, comfort and moisture management. Thermal liners that contain multilayer nonwoven materials absorb less moisture and remain drier, thinner and lighter.
As newer materials are developed, strides are being made in the turnout gear market; by maximizing the air insulation between each layer, multilayered spun-laced woven insulations are delivering enhanced thermal performance with only a marginal effect on breathability.
The Moisture Barrier
While the outer shell’s purpose is to protect the inner components, the moisture barrier provides resistance to water, chemicals, and viral agents. In order to serve these functions, the moisture barrier is constructed with an expanded PTFE (PolyTetraFluoroEthylene) permeable film barrier laminated to a woven or nonwoven flame-resistant substrate material.
Although the moisture barrier is critical to the success of the turnout garment, it is the most fragile component in the system and the element most likely to be damaged. To ensure that the moisture barrier is functioning properly and providing an adequate amount of support, it should be inspected on a routine basis.
Maintenance and repair of turnout gear is governed by the National Fire Protection Association’s 1851 Standard on Selection, Care, and Maintenance of Protective Ensembles for Structural Fire Fighting and Proximity Fire Fighting. NFPA 1851 mandates that an advanced inspection of all personal turnout gear ensembles and ensemble elements be conducted at a minimum of every 12 months or whenever routine inspections indicate that a problem may exist.
The Outer Shell
The outer shell of a firefighter’s turnout gear is the first line of defense, providing 25 percent to 30 percent of total thermal protection and shielding the inner components. Although the outer shell does not provide the majority of the thermal protection, it is vitally important to the turnout gear system as a whole.
The outer shell provides flame resistance and also protects firefighters from cuts and abrasions while they are on scene, whether it be a structure fire or a brush fire. Most importantly, it is the outer shell that maintains the effectiveness of the thermal liner and the moisture barrier.
Firefighters depend on turnout systems to protect them from burn injury, but firefighters can also help themselves by choosing what they wear under their turnout gear carefully. The under layers a firefighter wears can be additive to thermal protection, neutral or detrimental. Garments containing materials that can melt are detrimental to the wearer, whereas cotton base layers remain neutral.
To add to their thermal protection, firefighters should wear base layers that contain heat- and flame-resistant fibers. Although the conditions in which they work are often radically different, all firefighters, regardless of their specific jobs, can aid their fire protective gear by choosing base layers that are additive and offer increased thermal protection.
Increasingly, manufacturers of turnout gear are working with fire departments to understand their protocols and practices. Fire protective clothing is not a “one size fits all” business, and by working closely with fire departments during the product development stage, manufacturers can anticipate and address their needs.
For instance, it is commonly known that firefighters will often wait to engage the front closures of their turnout coats until they are in the truck. Progressive designers that are involved with fire companies will factor this observation into their products by designing components or closures that are more compatible with this practice.
The most important factor in the selection of turnout gear is to match the specific fabric combination and specifications of turnout garments with key department criteria. Fire companies are varied based on geographic location and climate, activity level, and crew, and it is critically important to take all of these factors into account when purchasing turnout gear.
To provide the maximum amount of protection for the firefighters wearing them, turnout garments must balance the need for thermal protection and for reducing the stress that the gear adds.
Mobility, breathability, comfort, moisture protection, thermal protective performance and total heat loss are all important considerations when selecting turnout gear.
Editor’s Note: Dr. Rich Young is a senior research chemist who has been with DuPont for 23 years, of which the past 10 were spent working on fabrics and systems for the protective apparel market. He has several patents on fabric and component technologies. He is a member of National Fire Protection Association (NFPA) technical committees for station wear and technical rescue gear and works with the technical committees on structural and proximity gear.