What are SFI and TPP Ratings?

SFI was originally run by the SEMA Foundation, which is an aftermarket automotive trade organization. "SFI" stood for "SEMA Foundation, Inc." SFI is now independent from SEMA, although the Foundation has maintained the name SFI Foundation, Inc. The foundation is a non-profit organization funded by the safety equipment manufacturers to ensure that products meet or exceed recommended standards.

SFI is a certification that demonstrates that the manufacturer certifies the racing equipment has been laboratory tested to meet or exceed SFI safety specifications. This gives consumers and sanctioning bodies a way to differentiate a certified product from one that is untested. Each sanctioning body will have a minimum suit rating required for competition. The standard for driving suits is 3.2A/X which is typically represented by a patch on the drivers’ left shoulder. The higher the SFI rating the higher the TPP value.

TPP rating (Thermal Protection Performance) is a calculated value that manufacturers use to rate the exposure to heat, energy and the approximate time before skin is subject to second degree burns (when skin starts to blister). The only way to increase the TPP value is by adding layers, so it’s always recommended to wear fire resistant Nomex underwear, socks, and hoods with every type of driving suit, especially single layer suits because it will double the minimum protection time.