the science behind your racing suit

Auto Racing suits use aramid fiber technology to meet SFI & FIA TPP standards

Auto Racing suits use aramid fiber technology to meet SFI & FIA TPP standards

Understanding aramid

We like to use the word aramid so we can categorize our racing suits - aramid & treated cotton.

Aramid means the use of an aromatic fiber. Aromatic fibers are highly engineered and 100% synthetic. They are marketed under different trade names, including Nomex (DuPont), Kevlar, Technora, Teijconex, Tawron and many more.

For the safety industries aromatic fibers have many desirable advantages including - excellent thermal, chemical and radiation resistance. Neither will they sustain combustion in air or melt when exposed to a flame. In addition the fiber is ultra strong but still light. And none of these properties can be washed out.

Treated cotton auto racing fabrics have literally been treated with a fire-retardant chemical, usually sprayed on. Their advantage is low cost but that’s about it. The fabric is heavy with a life expectancy of somewhere between 25 - 45 washes. Dry cleaning is problematic, and never recommended since unknown, possible hazardous, chemical are used.

Aramid racing suits are not identical. The outer, flame-resistant fabric has been woven with varying percentages of aromatic fibers - hence the price differences. (Nomex is very expensive.) The top auto racing suits are almost 100% aramid. You will be able to see the synthetic sheen on these suits. At the same time the weight drastically diminishes. In motorsports (thanks to sophisticated technology) frequently - less (weight) means more (money.)

Aramid sheets - Aramid thread

Aramid sheets - Aramid thread

Race driver Ellliott Sandler fire quite 1

Thermal protective performance (TPP)

sfi 3.2A and fia 8856-2000

SFI & FIA are renowned sport racing safety certification councils. They operate differently yet their mission is the same - to maximize driver and vehicle safety using current technology, science and testing. They publish and oversee minimum safety standards. The SFI and the FIA both use TPP (Thermal Protective Performance) to correlate their fire-resistant ratings. Their minimum TPP standards are identical.

SFI 3.2A Spec is used for fire-retardant apparel. FIA uses a code starting with 8856 followed by a date, which refers to the year that homologation was introduced. The most common current is 8856-2000. However we do know that the FIA is updating this standard.

Note: Please dismiss the common misunderstanding that a SFI 3.2A/5 suit means the suit has 5 layers.

To reach a TPP rating the suits material is subject to both a direct flame and a radiant heat measure. The thread, zippers, and cuffs also have to be tested.

To ease understanding the TPP results are translated into seconds. That is the number of seconds the fabrics prohibits the body from receiving a second degree burn.

SFI Rating TPP ValueTime to 2nd Degree Burn.

2A/1 - 3 Seconds (TPP 6)

3.2A/3 - 7 Seconds (TPP 14)

3.2A/5 - 10 Seconds (TPP1 9)

3.2A/10 - 19 Seconds(TPP 38)

3.2A/15 - 30 Seconds (TPP 60)

3.2A/20 - 40 Seconds (TPP 80)

The radiant heat portion of the spec is significant because the majority of racer burns are caused by heat transfer rather than direct flame. Insulation is the best way to prevent this kind of burn. Using multiple layers of fabric helps keep the heat source away from the skin longer because each layer creates air gaps that first have to heat up. The extra seconds gained with each layer are precious to a driver trying to escape from a burning car. (SFI Foundation)

How manufacturers achieved these TPP depends on the fabric, the construction and the numbers of layers used. A maufacturer has to submit samples of the fabrics as they will be used in the manufacturing process. Aramid suits’ fabrics are woven with fire-resistant threads such as Nomex (DuPont patented.) These are very expensive threads so companies weave the fabric with other organic materials such as cotton. However, this may cause the suit to not be so fire retardant so manufacturers have to add layers to achieve their regulated minimum TPP standard. This is why the less expensive suits are heavier. In auto racing less (weight) often means more (money.)

Other things to remember:

Keep your suit clean and do not wear while repairing your car. Grease, fuel, oils, fluids, and their fumes will soak into the fabric creating a conduit for fire, support the flames and lead to a combusible situation. We recommend using Molecule products to maintain and prolong the life of your suit. Molecule was created by a racer/chemical engineer for technical, fire-resistant fabrics.

Air layers increase the suits fire resistance. The suits quiltng is used for this. Tight suits take away air pockets. Adding fire-resistant underwear adds to the TPP. Certified underwear’s minimum TPP is 3 seconds and that’s in addition to the suit’s minimum TPP - and is increased by the air layer between the layers.

All suits pass the minimum TPP standard - the better brands surpass them. You are not just paying for that recognized logo.

Patches similar should have a fire-retardant backing and be attached used Nomes thread.

Embroidery, unless created with an aramid thread should only be attached to the outer layer of the suit.

Always follow the manufacturers instructions for the proper maintenance of your suit. In addition we recommend you do not hang the suit in the sun. UV rays are harmful to all aramid fabrics, including damaging to the color. When not in use, or off season, hang the suit - not fold it.