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Rapid advances in high‑performance fibers and the growing need for multi‑hazard protection are reshaping the protective textiles market, yet the real test of these innovations lies in the field. A compelling case in point is new research on how ballistic protection interacts with firefighter turnout ensembles—the highly engineered PPE firefighters rely on every day. Looking at technology on its own is no longer sufficient for practical real-world performance of PPE; understanding their combined effects demands a system‑level perspective.
Single-threat protection
For much of the modern era, fire service PPE has been engineered around a single‑threat model emphasizing heat and flame resistance. The outcome has been sophisticated, multilayer turnout suits that excel at shielding the body from extreme convective and radiant heat. However, this strength introduces a chronic tradeoff: these garments can trap metabolic heat and moisture, elevating physiological burden and heat strain.
In parallel, ballistic protection evolved to mitigate kinetic energy, using dense, rigid and, typically, non‑breathable aramid or ultra-high molecular weight polyethylene structures. On their own, ballistic vests deliver impact protection, but they also add considerable weight, sometimes up to forty pounds, and can significantly hinder ergonomics and performance.
When firefighters must wear both systems together, their interactions produce emergent effects that fabric- and component‑level testing do not inherently reveal. Hence the importance of system‑level evaluation: measure the combined ensemble to understand the true tradeoffs for responder safety and operational effectiveness.
Firefighters as multi‑hazard responders
The need for integrated evaluation stems from a profound change in the fire service mission. The traditional image of firefighters primarily battling blazes no longer fully reflects modern firefighter operations.
The most recent U.S. Fire Department Profile report indicates that 63 percent of departments, and nearly 97 percent of those serving populations over 100,000, provide Emergency Medical Services (EMS) for their communities. Surprisingly, only around 4 percent of emergency calls involve an active fire. Instead, roughly 64 percent of responses are medical, hazmat or other non‑fire incidents, with an increasing number occurring in volatile environments involving civil unrest or violence.
In response, departments across the country have begun purchasing and issuing ballistic vests as routine Personal Protective Equipment (PPE). The push toward “multi‑hazard” readiness now requires responders to execute interdisciplinary missions that can strain the thermal and physical limits of traditional gear.
The TPACC research approach
Although ballistic vests have been rapidly adopted across the fire service, departments have had little science‑driven guidance on when and how these systems should be used alongside traditional turnout gear.
Existing standards offer conflicting direction; for instance, ASTM E3348‑25 recommends to not wear body armor with turnout gear highlighting the lack of evidence regarding heat‑stress consequences, yet it also states that if body armor is worn, then it should be worn under the turnout gear to reduce melting hazards, since most armor carrier fabrics are not flame resistant.
To fill this gap, the Textile Protection and Comfort Center (TPACC) at North Carolina State University, funded by a Dept. of Homeland Security (DHS)-Federal Emergency Management Agency (FEMA) Fire Prevention and Safety Grant, launched a comprehensive system‑level research program. The project utilized a holistic approach, beginning with a review of current standards to understand current guidance along with a nation-wide firefighter survey to document current practices and perceived tradeoffs.
This was followed by three operational case studies examining ballistic use in active‑shooter and civil‑unrest incidents to ground the research in operational reality. Technical evaluations integrated sweating thermal manikin testing using “Newton” and “Liz,” advanced thermophysiological modeling, and human wear trials to quantify physiological load and ergonomic impacts.
To further assess ignition and flame‑spread risks, TPACC conducted bench‑ and full‑scale fire protection experiments, including a live-fire Molotov‑cocktail exercise. Central to this approach is the recognition that protective‑ensemble performance can best be understood when evaluated as a complete system. Isolated tests of ballistic fabrics or individual turnout‑gear layers do not capture the complex interactions among materials, closures, design features, fit, and overall ensemble integration.
While material‑level data remains critical, it represents only one piece of the performance landscape. By examining six different ensemble wear configurations, from basic station wear to full turnout gear paired with both soft and hard armor, TPACC was able to identify the practical tradeoffs associated with realistic firefighter wear strategies.
System‑level evaluation shows integrated tradeoffs
Using a system‑level approach was critical for understanding how ballistic vests interact with firefighter ensembles, revealing tradeoffs that are not apparent in isolated material or component only testing. When a vest is worn with a light station uniform, torso insulation nearly doubles and evaporative resistance increases almost threefold.
In contrast, adding a turnout suit over the same uniform raises both measures to nearly four times their baseline values. When the vest and turnout gear are worn together, the vest’s main effect is a further increase in evaporative resistance. Practically speaking, once firefighters are fully equipped in the combined system, this elevated evaporative resistance effect significantly hinders the body’s ability to cool through sweat evaporation, heightening heat‑stress risk beyond that already posed by wearing turnout gear alone.
These findings point toward a clear design priority for future ballistic and turnout systems: integrating ventilation pathways and improving evaporative efficiency while maintaining protective performance. They also suggest that departments may need to adjust work‑rest cycles, increase scheduled cooling breaks, and emphasize more aggressive hydration practices when firefighters operate in combined ballistic‑turnout configurations.
The system‑level approach also exposed pronounced ergonomic differences between covert (under‑the‑jacket) and overt (over‑the‑jacket) wear. Overt configurations consistently enabled better balance, quicker task performance, and lower perceived exertion because the vest could move freely over the turnout coat.
In contrast, covert configurations produced a “trapped and locked” effect, with the vest compressed beneath the bulky jacket, reducing mobility and shifting the wearer’s center of gravity. However, the same overt configuration that offered superior mobility also introduces a critical thermal hazard: many ballistic carriers are constructed from non‑flame‑resistant materials such as nylon or polyester, which can melt or ignite, potentially channeling flames toward the head and airway during incendiary exposures.
By examining both thermal and ergonomic outcomes together across a series of wear configurations, the system‑level evaluation made these interconnected tradeoffs visible. It revealed that optimizing mobility (overt wear) can inadvertently increase thermal vulnerability, while maximizing thermal durability (covert wear) can restrict movement.
This integrated understanding underscores a key opportunity for industry innovation: developing fire‑resistant ballistic carriers that maintain the ergonomic benefits of overt wear without compromising safety. Ultimately, the system‑level lens proved essential in capturing the full complexity of these interactions and in guiding more informed design, policy and deployment decisions for multi‑hazard firefighter protection.
Female Firefighters: addressing fit, sizing, and performance
Another long‑standing gap in PPE design is the reliance on a male‑centric anthropometric model. With women constituting nearly 10 percent of the U.S. fire service, a “one‑size‑fits‑all/most” is increasingly unworkable. TPACC explicitly prioritized system evaluations using both “Newton” and “Liz” sweating manikins, as well as both male and female participants, to probe differences in fit, microclimate formation, and ergonomic outcomes.
The system‑level results show that female responders encounter distinct tradeoffs. Differences in chest curvature and torso breadth influence how garments and armor seat on the body, shaping the formation (and stability) of insulating air layers. In many configurations, the female manikin registered higher evaporative resistance because standard gear failed to conform closely, trapping stagnant, humid air. In other configurations, the pronounced curvature created incidental “ventilation channels” that slightly improved heat dissipation relative to flatter male torsos.
Importantly, thermophysiological modeling indicated that at similar work rates (e.g., 3 MET), female firefighters can experience greater thermal strain (higher core and skin temperatures) linked to lower average sweat rates and different surface‑area‑to‑mass ratios. Ergonomically, although female participants often outperformed males in balance tasks, they were disproportionately constrained by universal‑fit vests that did not reflect their body shapes.
The takeaway is that the performance implications of ballistic integration is not uniformly distributed across the fire service, reinforcing the urgency of multi‑sizing ranges and distinct male/female shaping in future protective textile systems.
From evidence to policy: a tradeoff guide
The integration of body armor into fire service PPE is not a simple additive step; it creates a tightly coupled human/ textile/ environment system with high stakes. TPACC’s work shows that the benefits and nuances of integrated protection can be best realized when the risks and tradeoffs are quantified at the system level. For fire chiefs, training officers and frontline responders, this translates into an actionable “tradeoff guide” for policy and procurement.
A central policy‑relevant finding is the establishment of a 15 percent impairment threshold: an ergonomic performance decline greater than 15 percent in mobility or task speed should be considered a significant operational risk. This benchmark is grounded in evidence that firefighters’ performance drops by approximately 2.2 percent for every kilogram added to their ensemble6. Together, these markers provide chiefs with concrete criteria for evaluating the net impact of new gear and wear strategies.
Risk‑based deployment also emerges clearly from the data. For missions without fire involvement (e.g., EMS calls in warm zones), pairing ballistic protection with station wear can provide necessary protection with substantially less thermal burden than full turnout gear. Conversely, any scenario with credible fire risk should default to covert wear (or to overt systems with fire‑resistant carriers) to minimize ignition and flame‑propagation hazards.
This is especially relevant given the demonstrated risks of simple incendiary devices: many standard ballistic materials and carriers are not designed for flame, creating vulnerabilities that emerge from system‑level testing.
The Path forward: designing for the whole system
Ultimately, the complexity of wearing ballistics with firefighter turnout gear cannot be fully captured by fabric swatches, isolated resistance values or single‑threat standards. A system‑level methodology uncovers that the “best” configuration is mission‑dependent: overt wear may be justified to maximize mobility for medical response in warm zones, while covert (or overt with flame‑resistant carriers) is essential wherever fire exposure is plausible.
For manufacturers, the strategic direction is equally clear: prioritize ensemble‑wide ventilation architectures, evaporative efficiency and unique male/female sizing before marginal gains in ballistic panel thinness. For departments, adopt policy frameworks that use the 15 percent impairment threshold and the 2.2 percent‑per‑kg rule-of-thumb to balance protection, performance and survivability.
By coupling laboratory rigor and utilizing sweating manikins, modeling and controlled trials with operational case studies and human wear testing, this research bridges science and practice. The aim is not merely to stop bullets or withstand flames; it is to sustain responder health, mobility and effectiveness across the real missions that firefighters face today.
The future of protective textiles lies in understanding and engineering for the system as a whole, to ensure that those who run toward danger are equipped not just with layers of advanced materials, but with the integrated science of survivability.
Dr. Marc Mathews is a researcher with the Textile Protection and Comfort Center (TPACC) at NC State University. He is a former Marine CBRN Specialist and has been conducting research and development on Military and First Responder PPE for more than 20 years.
[1] National Fire Protection Association, US Fire Department Profile 2020
2 U.S. Fire Administration, Topical Fire Report Series, “Fire Department Overall Run Profile as Reported to the National Fire Incident Reporting System (2020)”, Volume 22, Issue 1, June 2022.
3 ASTM E3348/E3348M-22. Standard Guide for Body Armor for Non-Law Enforcement First Responders.
4 DHS-FEMA Assistance to Firefighters Grant Program, Fire Prevention and Safety Grant EMW-2021-FP-00855
5 Mica, M., 2026, “The effect of wearing ballistic vests on firefighter heat strain”,[Doctoral dissertation, NC State University, Wilson College of Textiles].
6 Kamali, R., 2025, “Ergonomic Impacts of Wearing Ballistic Vests on the Mobility of Firefighters”, [Doctoral dissertation, NC State University, Wilson College of Textiles].
Disclaimer: Points of view or opinions in this document are those of the author and do not necessarily represent the official position or policies of the U.S. Department of Homeland Security or FEMA.