Properly matching SFI ratings will enhance your chances of surviving a fire.
It may be one of the easiest and cheapest safety measures you can take. Buy some fire-retardant underwear. Remember what we said earlier; the majority of racer burns are caused by heat transfer rather than direct flame? Good, because insulation is the best way to prevent this kind of burn. How do you get additional insulation in your racing suit? The answer is easy. Using multiple layers of fabric helps keep the heat source away from the skin longer because each layer creates air gaps that have to heat up before that heat can transfer. The extra seconds gained with each layer are precious to you safely escaping from a burning car.
Fire resistant underwear should be worn with every type of driver suit, especially single-layer suits. In the case of a single layer suit, having FR underwear will double the minimum protection time. While fire retardant underwear falls under a different SFI spec (3.3 for Driver Accessories), it does use the same TPP and flammability tests as the driver suits.
Adding fire retardant underwear, like the Carbon X Bob Bolles is wearing here, can, in som
Let's do just a little more math. If you add underwear that has a TPP rating of say 10 to a suit that has a TPP rating of 23, you now have a total protection time of over 17 seconds. One final thought on layers and fit, a suit and underwear combination that is worn too tight will compress the air gaps created within the layers and allow heat to reach the skin faster. So make sure that you have the proper fit in your suit and accessories.
Beyond a good fit and having extra layers, there are other things you can do to optimize the protection performance of your driver suit. First and foremost, avoid wearing your suit while working on the car. We know that changing in and out of your suit between heat races and features may not only be inconvenient but in some cases even impossible. However, getting dirt and residue while working on the car on your suit ruins an expensive piece of equipment and invites a fire to burn you. Grease, fuel, oil, and even cleaning fluids can soak into the fabric and support the flames of a fire. Beyond the obvious, when any of those fluids burn they will also produce steam when exposed to heat and cause liquid vaporization burns.
Finally remember to follow the manufacturer's cleaning and care instructions to the letter when it's time to wash your racing suit. This goes for gloves, shoes and underwear too.
Restraints, window nets and any other safety harnesses must be maintained, inspected, and replaced or rewebbed every two years for one simple reason-over time they degrade from exposure to the elements. Prolonged exposure to sunlight can cause degradation of the webbing, the fibers that make up the webbing and the thread that holds the whole assembly together. As that degradation takes place, the webbing looses its structural integrity.
The webbing used in motorsports restraints is typically made with DuPont Nylon 6-6 or a similar product. According to test data from SFI, webbing loses about half of its strength in one year. Chart B (above) shows the rate at which typical belts will degrade over a 24 month period.
Looking at that graph, it doesn't take a rocket scientist to figure out why you need to replace the webbing every two years. Even a moderate g hit would easily snap old and weakened belts. Replace them or at the very least have them checked for recertification, if you don't, make sure your life insurance policy is paid up.