In a message dated 9/5/02 8:28:31 AM US Eastern Standard Time,
samandgreg@netins.net writes:
> When recently looking for a driving suit, I read that there is a material
> used that is basically cotton that has been treated to make it fire
> proof. The article stated that this material was more comfortable but that
>
> the treatment washes off over time. I ended up with a Racequip nomex suit
> that offered about 30 seconds of protection. They had two suits both rated
>
> /5, but one was 20 seconds and the other was 30 seconds. My opinion is
> that the time before you burn is the only really valid measurement. I
> figured I needed the extra 10 seconds to remember to remove the steering
> wheel.
>
> Can anyone verify or deny what I heard about the treated cotton material?
>
Maybe this will help:
TPP (Thermal Protection Performance)
The Speed Equipment Manufacturers Association (SEMA) was formed in 1963 with
the central purpose of developing of product specifications for the suppliers
of equipment used in racing. SEMA later formed SEMA Foundation, Inc. (SFI),
to organize and manage an expanded industry specification program. The name
was shortened to SFI Foundation,Inc.(<A
HREF="http://www.sfifoundation.com/driversuit.html";>
http://www.sfifoundation.com/driversuit.html</A>)
One of SFI standards (3.2a) is a specification for racing car driver garments
that includes tests for measuring garment material flame resistance, heat
resistance, and thermal insulation (based on Thermal Protective Performance
or TPP testing). The specification contains a rating system based on the
garment's TPP test results. The TPP test evaluates the garment materialbs
thermal insulation in the presence of both direct flame and radiant heat.
The purpose of the TPP is to measure the length of time that the person
wearing the garment can be exposed to a heat source before incurring a second
degree, or skin blistering, burn.TPP results are reported as a time-to-second
degree burn. This result is derived from a complex mathematical formula that
related the heat transferred through the garment material to the amount of
energy that would be required to cause a second degree burn. TPP results may
also be reported as a rating. This rating is the time-to-second degree burn
multiplied to the heat exposure level that the material is exposed to
(usually 2.0 calories per square centimeter per minute b equivalent to a
fireball). The higher the garment TPP rating, the more time that is required
before a second degree burn will occur. Below are the SFI ratings based on
TPP results (shown to the right of the slash mark on the driver suit patch)
with the corresponding times to a second degree burn:
SFI Rating TPP Rating Time to 2nd Degree Burn
3.2A/1 6 3 Seconds
3.2A/3 14 7 Seconds
3.2A/5 20 10 Seconds
3.2A/10 38 19 Seconds
3.2A/15 60 30 Seconds
3.2A/20 80 40 Seconds
Tom Butters
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