Todd Herring, Vice President of Product Innovation and Strategy, Fire-Dex talks about how lightweight turnout gear is evolving to reduce heat stress and fatigue.
For many years, the design logic behind turnout gear was straightforward: heavier and thicker often meant more protection. That approach grew from legitimate priorities. Firefighters need protection from direct flames, radiant heat and steam, and turnout gear evolved with added bulk, weight, layers and structure to deliver it.
But firefighters are rarely standing still. They climb stairs, force doors, pull hose, drag victims, crawl low, reach overhead and work for long periods under load. In that setting, the heaviest gear is not always the smartest. If a garment traps heat, restricts movement and accelerates fatigue, that matters—a lot.
Heat stress is one of the main risks firefighters face every time they gear up.
In 2024, an NFPA report found that overexertion or strain was the leading cause of on-duty firefighter fatal injuries (40 of 62 fatalities), driven largely by heart attacks (11 fatalities) and other medical events associated with physical stress, rather than by burns or trauma alone.
Independent testing by NC State University and Florida State University shows how that risk builds: hearing impairment can begin at 99.5°F, motor impairment at 100.2°F, cognitive impairment at 100.9°F and heat stroke at 104°F.
As heat load increases, core temperature rises, affecting coordination, judgment and physical control. Fatigue sets in faster, recovery takes longe and the risk of collapse, injury or a cardiac event increases.
What has changed is the industry’s understanding that heat management is a core part of protection. Once viewed largely as a comfort issue, reducing heat burden is now increasingly recognised as an important contributor to firefighter safety.
One of the biggest shifts has been a more strategic approach to turnout construction.
Earlier designs provided consistent protection across the entire garment, reflecting the priorities and technology available at the time.
Modern lightweight designs still protect the whole body, but with greater attention to where heat and moisture accumulate during realworld operations. That is why some designs now use breathable panels or “vent zones” in places like the armpits, inner thighs and behind the knees.
In some designs, these areas use lighter, more permeable layer constructions to improve moisture vapor transfer, while maintaining thermal protection. The goal is to increase the rate at which heat and sweat vapor can escape.
The body already knows how to cool itself, sweat is not the problem—trapped sweat is. If moisture and hot air stay sealed inside the coat and pants, the body loses one of its main cooling mechanisms.
Researchers at the Illinois Fire Service Institute demonstrated this using a FLIR camera and tracer gas to visualize airflow through turnout gear incorporating engineered ventilation zones. Gas released inside the garment exited through specific vent locations rather than diffusing randomly or remaining trapped.
The test showed how airflow can be directed through defined openings, driven partly by pressure differences between the inside of the garment and the external environment. As movement increased, airflow increased as well, suggesting that ventilation can function as a dynamic system during firefighting.
The second major change has been reducing composite weight at the material level.
Outer-shell fabrics are no longer designed solely as durable protective exteriors. They are increasingly engineered to reduce heat burden while maintaining flame resistance and thermal protection at a lower composite weight.
Some achieve this using ripstop and twill constructions. Reinforcing yarns woven into ripstop fabrics help limit tearing, while twill weaves improve flexibility and drape. Together they provide strength and abrasion resistance without unnecessary stiffness or mass.
Lighter fabrics also expand the possibilities for composite engineering. TECGEN71 fabric, for example, combines ripstop and twill construction to reduce weight and improve breathability, while remaining compatible with some of the lightest thermal liners and moisture barriers available. This enables lower-mass composite builds, including single-layer thermal liner configurations that would be harder to achieve with a traditional outer shell.
The outer shell contributes significantly to total composite weight and the key comfort-and-protection metrics that matters most in the field:
Turnout gear isn’t defined by a single layer. It’s the performance of the full composite system working together: outer shell, moisture barrier and thermal liner.
Rather than making any one layer lighter or heavier, the goal is finding the right total composite weight to meet TPP requirements while still supporting breathability and comfort. Each layer plays a role, and changing one impacts how the others perform.
Lighter outer shells can create more flexibility in achieving that balance, allowing designers to optimise protection, moisture transfer, heat dissipation and overall garment burden without compromising performance elsewhere in the system.
A third important change is that the industry is starting to question whether one set of turnout gear should do everything.
For years, structural firefighting gear has been the default choice for a wide range of calls, where structure fires, vehicle extrication, EMS support and technical rescue often all meant the same PPE. That approach made sense when options were limited and standards were narrower.
But departments now manage far more non-fire incidents than working fires. NFPA reports 1.3 million fire calls in 2024, set against more than 35 million other calls for assistance.
Every call carries risk, but not every call demands the same level of thermal protection. What is demanded in all cases is mobility, reduced burden and the ability to work comfortably for longer periods, and that is driving more discussion around task-specific gear as a complement to traditional turnouts.
We are seeing more interest in lighter, more breathable systems for nonstructure work, and more emphasis on matching PPE to the actual hazard profile of the call—for instance, garments designed specifically for the realities of fire investigation. The goal in most cases is to avoid overloading the firefighter with unnecessary weight that contributes to heat retention, fatigue and strain.
This also changes how departments approach PPE programs: instead of evaluating a single turnout set in isolation, they are starting to think in terms of a system of gear options. Structural gear for high-heat environments, alternative ensembles for lower-heat and higher-duration work, each with its own performance certifications.
Protection on today’s fireground must account for mobility, heat burden and the ability to keep performing under stress. That reality is pushing turnout design in a more deliberate direction that looks beyond thermal defense and pays closer attention to how weight, heat transfer and task demand work together.
Lightweight turnout gear is about engineering protection more precisely around the way firefighters actually move. That means building systems that help reduce unnecessary burden, support heat dissipation and improve wearability, while still delivering the protection required for the job.
That is a shift worth reinforcing, because turnout gear performs best when protection and function move together
