While each and every one of us know that a good firesuit is probably one of the most important pieces of safety equipment you can own, the proper care of your suit will make a significant difference in its performance when you need it most.

In order to understand the vital role proper care plays in the performance of your suit, we also must consider the type of suit or, more to the point, how the suit's manufacturer achieves fire retardancy. To do that, let's take a review of the different type of fire-retardant suits available today.

While there are numerous fire-retardant materials on the market, three that are often seen in the motorsports industry are fire retardant (FR) cottons, Nomex, and CarbonX. You may hear about other FR materials, such as Difco/PBI, Basofil, or Proban, but these tend to be used more in items such as firefighter suits and fire-retardant upholstery. But that doesn't mean you can't find them in the racing world, as Proban and PBI have both made a push into motorsports recently.

All of those FR materials perform admirably when tested, and in many cases, you will find that manufacturers offer suits made from several different materials or a combination of materials. For example, you can buy a custom suit made of either Nomex or CarbonX from Simpson Race Products.

The quality of any fire-retardant material can be determined by looking closely at two measuring factors: Limiting Oxygen Index (LOI) and Thermal Protective Performance (TPP). LOI is the most commonly used measure for flame retardancy and refers to the amount of oxygen needed in the atmosphere to support combustion. If a fiber or fabric has an LOI of 25, that means that oxygen needs to be present in at least 25 percent of the air for the fabric to burn. Consequently, a higher rating equals more fire protection. Many fiber manufacturers achieve high LOI ratings by chemically treating their fabrics with a flame-retardant finish. The downside is those chemicals can be washed and worn off over time without proper care. You won't often see LOI in race suit literature, but it's an important factor in good fire protection.

On the other hand, TPP refers to the garment's ability to provide thermal protection when exposed to both direct flame and radiant heat while taking into account the length of time before a person is subject to second-degree burns. While that's a mouthful, TPP is the second most important number you need to know when firesuit shopping. The TPP rating is derived from a mathematical calculation performed with the results of a sophisticated test procedure that utilizes two different heat sources, sensors, and the fabric to be tested. The TPP rating is divided in half to determine the number of seconds until the human tissue reaches a second-degree burn. For example, if a particular fabric has a TPP rating of 35, it takes 17.5 seconds until a second-degree burn occurs in a flashover situation. See the chart to the right.

The only way to increase a TPP rating is through adding multiple layers. However, as you increase layers, suits get bulkier, and bulk does not equal comfort. Your goal in selecting a firesuit should be the balance of comfort with maximum protection.

Regardless of whether your suit is made of CarbonX, Nomex, Proban, FR cotton, or something else without the proper care its LOI and TPP can be adversely affected, especially over longer periods of time.

Proban & FR Cottons
Certain fabrics such as Proban can be washed using conventional methods. However, you shouldn't use detergents based on soap or detergents containing sodium silicate or metasilicate when the wash or rinse water hardness level is greater than 3 degrees Clark (45ppm calcium carbonate). What? In plain English, if you've hard, water don't wash your firesuit, get it professionally cleaned.