Several years ago, a research and development meeting hosted by FEMA in Washington, D.C. looked at several projects funded by the Assistance to Firefighters Grant Program. One of the projects was ‘Cardiovascular and Biomechanical Responses to Firefighter and PPE’ presented by Denise Smith and Gavin Horn of the University of Illinois Fire Services Institute. Their study documented cardiovascular risk factors among over 100 firefighters and the effects of different PPE configurations on physical and biomechanical responses to live firefighting activities.
Among their major findings were:
• 18 minutes of simulated firefighting activity (simulated hose pull,
search and rescue, forcible entry, stair climbs, and live burns) caused significant physiological disruptions including an increased heart rate of 75 bpm and an increased core temperature.
• Simulated firefighting activities caused a significant increase in platelet numbers and platelet activation, resulting in faster clot formation.
• The same activity caused an increased level of coagulation and significant changes in clot breakdown.
Along with these findings and several others the project offered many recommendations. One such recommendation was that manufacturers and fire service organizations continue to identify and test designs and interventions directed at producing lighter and more breathable PPE.
Reducing heat stress has been a constant challenge, especially in relation to reducing firefighter fatalities. As an occupational hazard, heat stress presents itself in several ways. In a 2017 National Fire Protection Association report, there were over 2,400 reported thermal stress injuries to firefighters in 2016. Unfortunately, prevention goes against the demands of the occupation. Evaporative cooling is ineffective when wearing three-layer PPE ensemble for fighting fire. Add the physical demands to the severe heat and the risk of injury or fatality due to heat stress is multiplied. This risk multiplication is shown in the number of medical complications and heart attacks due to an increase in core temperature. The NFPA states that cardiac-related events accounted for 38% of firefighter deaths in 2016 and 42% in the past 10 years, making it a leading cause of line of duty deaths.While fire departments and firefighters may have little choice in designing their structural firefighting PPE, there is a bit of freedom in selecting what they will wear under their PPE. New materials are now available that have an effect on moisture management and heat stress.
Moisture under a shirt can in some circumstances contribute to burn injuries since wet PPE can be more conductive than dry PPE. Moisture can act as a coolant, but it can also as a conductor. When moisture acts as a conductor, it is also a heat sink. To protect firefighters from thermal events and heat stress injuries, the first layer of protection should be the first layer on the skin.
The Oklahoma City Fire Department switched to FireDFND after having been wearing cotton t-shirts. “The DFND shirts provide more flame protection and wick away moisture better than does cotton. Additionally, these shirts are just more comfortable and last longer,” said Battalion Chief Benny Fulkerson.
“The wearability was just better suited for firefighting. They wear well under structural firefighting gear and hold their color well even after a year of use,” said Fulkerson. He added that reviews of FireDFND by firefighters were positive concerning comfort, fit, wear, and durability.
The FireDFND collection by DFND is designed by firefighters for firefighters. The FireDFND Collection is being manufactured using a fabric supplied by TenCate Protective Fabrics called TechT4TM with CooldermTM Technology. TenCate TechT4TM is an inherently FR base-layer fabric. TenCate TechT4TM is a non-contributory FR fabric, meaning that it will not melt, ignite, drip, or char. This is in accordance with the standards set forth by the Department of Homeland Security’s Dual Certified NFPA 1975/1977 Project, more commonly known as the DHS Wildland Firefighting (WLFF) PPE Garment system.
Quality of workmanship, comfort and style of garment, manufacturer exemplary service and willingness to meet specification needs, are what led the Los Angeles County Fire Department to begin using DFND.
Captain Tim Vanderlip said that following recommendations of a study and report commissioned by the Department of Homeland Security to address the occurrence of heat-related injury/illness to firefighters engaged in wildland firefighting activities, the department began a review of shirts by two manufacturers. “A team of individuals were assembled to head the evaluation and garments were distributed to select end users for wear trial input. This testing process was inclusive of members assigned on the Department Equipment Development Committee and concluded after final interdepartmental results, “said Captain Vanderlip.
Department logo/artwork was finalized in the post bid process and the clothing was pre-ordered in bulk, packaged two each per individual along with Dual Compliant Wildland Tactical Pants, and then distributed to over 3,500 members department wide. Vanderlip said “The feedback continues to be overwhelmingly positive, long after wear trials and nearly three years of Department-wide usage. The fabric remains protective and moisture-wicking, which contributes to individual thermal heat loss. We have not seen issues with the fabric fading or pilling, even after countless washings.”
“The garment construction and style are durable and comfortable. Some personnel have evaluated other products by DFND, such as compression gear, workout attire, and undergarments, and have found the same superior quality and durability in manufacturing. DFND and the local vendor have provided exemplary service and delivery to the department,” added Vanderlip.
When used as a base layer underneath FR station wear, turnout gear or other FR gear, TechT4TM garments enhance comfort and provide an extra layer of protection, while cotton may not. Other base-layer fabrics, like many popular, moisture-wicking blends that include polyester, spandex or nylon, could melt to the skin during a thermal event, which can cause additional injury.
Like athletic performance base-layer fabrics, the fiber blend of TenCate TechT4TM provides excellent moisture management. TenCate CooldermTM Technology provides an evaporative cooling effect in warm climates and helps to regulate body temperature in cooler climates. Sweat and moisture are drawn, or wicked, away from the body and dispersed over a wide area of the fabric to ensure quicker drying times.
The FireDFND product line is not limited to short sleeve shirts. Fire departments can also incorporate long sleeve shirts, shorts, boxers, and long johns into their inventory of station wear.
“The product DFND offered was of high quality that our department really saw value in,” said Captain Kaaina Keawe of the Hawaii Fire Department. “We did not have any specific in-department testing process. We were sent some samples for personnel to try on before our first purchase. This allowed any personnel interested to try on and feel the material. The reason for offering it was that up to that point we only had cotton shirts that didn’t provide the best practicality for fire fighters. Secondly, they would continue to fade, shrink, and have odors after a short period of time. Which in turn would cause them to need more frequent replacements. DFND offered a product that was not only fire resistant, but also anti-fading, anti-shrinking and anti-microbial,” Captain Keawe added.
\When asked about factors that led to choosing FireDFND, Keawe said that in addition to product quality, customer service was equally high, “The biggest reason for selecting DFND was due to the customer service we received from DFND and specifically Laura Burnett. Due to the distance and also the fiscal structure of our department we had significant hurdles to overcome. Laura was relentless in helping us find solutions, remaining extremely flexible and accommodating throughout the entire process. Even to this day as situations change and flex Laura and DFND always protect our interest.” In the field, Captain Keawe said the FireDFND shirt selection was well received, “Everyone loves the shirts and for many I have spoken to personally, agree that ever wearing a cotton shirt on duty again would be very difficult.”
In the wildland firefighting environment, this wicking action will help to increase firefighter performance by working to keep core temperatures lower. A comparable cotton shirt takes about 75 minutes to dry while the FireDFND Collection shirt with TechT4TM will dry in less than 25 minutes.
When adding TechT4TM with station wear or thermal barriers that use TenCate CooldermTM Technology, the moisture-wicking properties are actually enhanced further, pulling away and dispersing moisture in the ensemble. Like all CooldermTM Technology fabrics, TenCate TechT4TM is hypoallergenic, less likely to irritate the wearer’s skin. TechT4TM is further enhanced with MicrobeSHIELD, to reduce the potential of body odor.
FireDFND Top Features Are:
• Inherently FR
• No chemical treatment and will not wash out
• No Melt, No Drip, No Char
• Highly Breathable and Moisture Wicking
• Non shrinking / Non fading
• Anti-Microbial Protection and SPF 20+
• TechT4 CooldermTM Technology
• Extended Length
• Meets ASTM values in coordination with NFPA