BY ANTHONY DI GIOVANNI
Selecting fire protective clothing is not a simple task; it requires extensive analysis to ensure that the garment selected is suited for the needs of each specific fire department. The many factors that must be considered often make the process confusing and time-consuming. Influencing this process are the manufacturers of individual components and organizations such as the National Fire Protection Association (NFPA) that set standards related to product stewardship.
In this process, manufacturers often lose sight of the fact that the first priority of firefighters is emergency response and training, not analyzing and reanalyzing the properties of fire protective clothing. As manufacturers, we are responsible to present those facts simply and in a way that relates to the user’s needs.
STANDARDS
The two most recognized standards regulating fire protective clothing are NFPA 1971, Standard on Protective Ensemble for Structural Fire Fighting, and the European Committee for Standardization’s EN-469 Performance Requirements for Protective Clothing for Firefighting. Both standards specify safety parameters for fire protective garments. By referencing industry-recognized test methods and procedures, manufacturers submit their respective garments for third-party testing to determine whether they meet those requirements. Both standards include severe testing that allows firefighters to determine a level of field performance that meets their department’s needs. When compared, both standards are thorough in their assessment of a garment’s performance. NFPA 1971, however, offers some slightly more elevated requirements for heat resistance, garment breathability, and overall garment integrity. This mainly relates to the tactics required to fight fires in structures typical to North America.
MATERIALS
Many materials are available for fire protective clothing, and the combined fabric components selected for a garment determine many of its performance characteristics. Fire protective clothing typically consists of three layers: outer shell, moisture barrier, and thermal liner. Although each layer serves specific multiple functions, as a composite, they are expected to provide the firefighter with adequate heat, flame, liquid, chemical, and mechanical protection (Figure 1). As with the physical properties of most materials, there are always “give and take” factors to consider. Most notable is the relationship between thermal protection and breathability. Although maximizing both is desirable, this relationship is inversely related. Fire departments requesting lighter, more mobile gear must be aware of the reduced thermal protective factors attendant to such gear. This means that fire departments selecting this gear may have to consider readjusting such aspects as interior attack strategies to reflect this reality.
 Figure 1. Protective Clothing Components and Properties |
Another important difference among fabrics is the fiber composition and form. Some fibers will radically transform when exposed to severe heat or flame, thereby allowing them to absorb more heat on the surface layer. Others will not transform but may allow marginally more heat to be dissipated within the inner layers. Also worth mentioning is the difference between fabrics that are woven using multifilament fibers and those using more traditional spun fibers. Multifilaments consist of smooth uniform yarns that provide enhanced tensile strength, water resistance, interfacial slipperiness, and wearability.
Field experience has proven that there is much emphasis on the outer shell material, perhaps because it is the most apparent component and its condition is often equated with overall gear performance. Although the shell is important, it provides only between 25 and 30 percent of the total thermal protection. The outer shell material provides a first line of defense against flame, cuts, and abrasions. Added benefits are slipperiness for enhanced mobility and water absorption, especially once the water-repellent finish has worn off. Although all outer shells possess a mill-applied water-repellent finish, its effectiveness can be reduced through soiling, abrasion, and laundering.
The moisture barrier consists of a permeable film barrier laminated to woven or nonwoven substrate material. It has been proven that ePTFE (expanded polytetrafluoroethylene) films offer enhanced resistance to heat and chemical exposure while providing better long-term durability. Durability is also a factor when selecting a moisture barrier with woven vs. nonwoven substrate. The woven substrate outlasts the nonwoven backed fabric. Conversely, the nonwoven substrate will typically contribute marginally more to the garment’s overall thermal protective factor.
The thermal liner is also a double-layer fabric with a facecloth material quilted to a nonwoven batting insulation. Together with the moisture barrier fabric, these components account for up to 70 to 75 percent of the protective ensemble’s thermal protective performance. Since thermal protection is the most important thermal liner function, other factors such as water management and interfacial slipperiness must also be factored in. The facecloth material is closest to the skin; hence any increase in friction will typically result in more exertion by the wearer. Fabrics containing some or all filament will offer better slipperiness properties.
Water management in thermal liners can be more complex. Facecloth liners containing some or all filament inherently have less affinity for water. This can enhance the wicking and even shedding properties particularly as the filament content is increased. This offers the firefighter a faster drying time between calls. However, it is important to highlight that water or wetness in a thermal liner can be dangerous for firefighters, as it can delay recognition of a high-heat zone by providing the firefighter a misleading heat sink effect.
The second layer of the thermal liner, the thermal insulating component, is also quite varied. Typically, it consists of nonwoven battings made of aramid or aramid blends. Thickness is often directly related to thermal performance but inversely related to breathability. Newer, multilayered, spun-laced woven insulations are delivering on enhanced thermal performance with only a marginal effect on breathabilty by taking full advantage of the insulating air between each layer.
When determining the right fabric combination, it is important to note that it is not just a matter of “good, better, best”; rather, it is a methodical approach that looks at predetermined factors. All fabrics that are certified provide an industry-recognized level of protection. However, it is of great importance to match the fabric combination with key department criteria such as attack strategies, environment, crew demographics, type of calls, and climate.
DESIGN
In safety or industrial applications, design is synonymous with ergonomics, defined by the Merriam-Webster On-Line Dictionary, as the “applied science concerned with designing and arranging things people use so that the people and things interact most efficiently and safely.” When developing fire protective garments, it is important that designers work closely with firefighters to develop products that respond to the needs of the user. Designers make use of engineered pattern configurations that maximize mobility and optimize safety and protection while maintaining obvious factors related to basic functionality.
Of greatest concern for the firefighter is unobstructed range of motion, important not only for movements typically associated with structural firefighting but also with technical and medical rescue, which can make up as much as 80 percent of the firefighter’s daily tasks. Given that fire protective clothing is a three-layer composite, design must aid ease of movement. Shaping the garment and providing gussets in key spots can usually achieve this, but never at the expense of adding more fabric or weight, which would defeat the purpose of design engineering (Figure 2).
 Figure 2. Differentiation in Design |
Mobility is particularly important in the areas of the body where bending and twisting occur, typically the midtorso and limbs. Shaping the garment will achieve this. Some more modern designs provide a height differential between the front and back of the body. The front of the pant will be lower than the back section and, conversely, the front of the coat will be raised to ease bending when climbing and running. Designers of these more advanced garments will also shape the sleeves and pant legs to mimic the natural stance of the arms or legs, providing enhanced comfort and freer movement for the firefighter.
Other performance factors related to garment design include functionality and enhanced safety. Designers should attempt to anticipate possible vulnerabilities in garments related to firefighter tasks and practices. For example, it is a commonly known fact that firefighters will often engage the front closures of a coat only once in the truck. Progressive designers, involved with firefighters, will anticipate this in their design by building in components or closures that are more compatible with this practice.
Design differentiation is dynamic and related to the changing tasks of the firefighter as well as the changing demographics of fire departments. The manufacturer of the fire protective clothing must anticipate and recognize the needs of fire departments by working closely with them during product development. Fire protective clothing is not a “one size fits all” business.
ANTHONY DI GIOVANNI is strategic marketing director for Bacou-Dalloz Protective Apparel Ltd., which manufactures and markets fire protective clothing under the Securitex and FireProtex brands. He is a member of the National Fire Protection Association 1971, Standard on Protective Ensemble For Structural Fire Fighting, committee.
