Selecting the Best Base Layer


Category : Responder Safety

We know that your firefighter turnout gear serves a distinct purpose – it must provide protection from a variety of factors you face each and every time you go out on a call. In order to do that, by nature that gear must be heavy and insulated.

This in turn puts an increased strain on you and your body’s health and wellbeing. Heatstroke, cardiovascular, and thermoregulatory strains are a real danger for firefighters. According to the NFPA, in 2016, 27% of fireground injuries were due to overexertion and strain.

Fire departments often invest a lot of time, thought and expense into providing the very best, most effective turnout gear for their firefighters. However, little to no thought is usually put into what can be considered the foundation of a firefighter’s uniform – the base layer.

Historically, many firefighters wore a simple, white 100% cotton t-shirt under their gear. However, with the advent of technologically advanced textiles and fabrics, most notably synthetic materials, that began to change.

In the late 1990s, materials we now know as moisture wicking or dry-fit began to be used by athletes, football players in particular, to help regulate their body temperature and reduce moisture absorption in their uniforms.

Dri-fit baselayers are an insulating layer between the wearer’s skin and outer apparel. They help maintain a constant, comfortable body temperature, while also wicking, or pulling, away moisture from the skin and redistributing it around the base layer so that it dries quicker.

These baselayers were used to both keep players cool in hot weather conditions, as well as help keep them warm during cold weather conditions. Eventually, athletes in other sports, as well as different outdoor professions took notice and began to utilize this technology. Everyone from joggers to fishermen and the military took advantage.

With the heat and stress firefighters face on a daily basis, it’s no wonder they made use of them too.

Research shows wearing a base layer under structural firefighting gear actually has little influence on the body’s physical response to activity or recovery. The reason being that the extreme conditions the body is subjected to and the subsequent heat and sweat produced overwhelm the fabric’s technology and layers, rendering them unlikely to help keep the user cool.

However, as a firefighter, it’s likely you’ll wear the same base layer, be that a dry-fit shirt or a cotton t-shirt, all throughout your shift, so that when duty calls, you’ll throw on your turnout gear over the base layer and be off.

Because the dry-fit base layer provides better comfort during everyday activities, it’s preferable to wear this type of base layer over the standard cotton t-shirt.

What to Consider in a Base Layer

Whether you choose to believe the studies or not, many firefighters do accept that wearing a base layer helps keep them cooler and dryer under extreme conditions.

When choosing baselayers, there are several factors to think about.

  • Protection

  • Materials

  • Comfort

Protection & Materials

There are four general titles for fabric weights – ultra-lightweight, lightweight, mid-weight, and heavyweight.

As a firefighter, you’re looking for lightweight to ultra-lightweight fabric which is intended to help wick away moisture and retain a minimal amount of heat.

Known as the world’s leading supplier of inherently flame-resistant fabrics, TenCate created the TenCate TECH T4 base layer fabric which provides inherent FR protection. This fabric is designed to not ignite, melt, or drip, all crucial components for active firefighters. Compared to cotton, which is highly flammable and does not provide any moisture wicking capabilities at all, the TenCate TECH T4 absorbs any moisture and spreads it over a wider area of the shirt so that it can evaporate quicker, thus keeping the user dryer and more comfortable. This technology also promotes a cooling effect on the user and by using an ultra-lightweight material, guarantees the most comfort.

At the very least, you should look for materials that offer high-performance, flame-resistance, like synthetic polyesters. Flame resistant is an absolute must, for obvious reasons.


Many people find dry-fit clothing more comfortable in general, and that is indeed a major draw for using it as a base layer under your turnout gear. However, the sizing you choose also plays a huge role in your comfort level, and should not be overlooked.

You want to ensure that you have maximum ease of movement in whatever base layer you select. If you choose a base layer that’s too tight, you’ll feel bound in and like you’re constantly readjusting it to get it just right. On the other hand, if you pick a size that’s too big or loose, you may find that it bunches up underneath your turnout gear and isn’t very comfortable at all.

Think about your very most comfortable t-shirt, the one you go to when you have the day off, and try and match the size of that shirt with the size of base layer you pick.

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