Re: Helmets, S vs M <getting kinda long>

[Jefrem Iwaniw <jiwaniw@xxxxxxxxxxxx>]

On Fri, 18 Dec 1998, Michael, Don wrote:
=09<snip - stuff that I agree with>
> =A0
> I don't know for sure, but I suspect an M-type helmet has a much less
> stringent quality spec and is considered suitable to get by motorcycle
> helmet laws in some states. M-type is not suitable for much else. They're
> one small step (maybe) above a bicycle helmet.=20

Don, sorry, that's just not very true.  M-rated helmets don't have nomex,
and don't have to pass the "bounce-against-the-rollcage-like-a-seed-in-
a-maraca" test.  There are some other differences -- here's the result of
an analysis done by the PCA's Paul J. Amico of the additional
characteristecs of the SA-95 spec vs. the M-95 spec:

<begin things that SA-95 has...>
- ------------------------------------------

5=3D29 Flame Resistance - whether the helmet will withstand exposure to
direct flame

- ---------------------------------------

It is also important to remember that the visual field requirements
are based on the needs of people participating in well regulated and
controlled even ts.  For this reason, the requirements are
considerably less than those the Fo undation requires for street use
headgear such as for motorcycle helmets.  Be absolutely certain that
the helmet and face shield permit you adequate vision for every
intended use.  Specifically, if your automotive racing helmet is on ly
sufficient for controlled track events, don't use it for street
motorcycling.

- -------------------------------

This 1995 Standard establishes performance characteristics
particularly suited to the conditions of automotive racing which may
include complete harne ss and restraint systems, elaborate roll bar
cages, and reduced visual fie ld requirements.

- --------------------------------

A fourth anvil is used to test impact protection for repeated strikes
a gainst a roll cage assembly.

- -------------------------------

Since race drivers are frequently unable to escape quickly from
acciden t involved vehicles, their helmets must also provide some
measure of pr otection against fire.  Exposed helmetcomponents,
whether internal or extern al must be flame resistant.  They must not
be combustible and when exposed to hi gh temperatures, must self
extinguish when the heat load is removed.

Helmet components are tested separately for flame resistance by ex
posing them to a direct propane flame of a specified temperature for
specified periods time.  When the flame is withdrawn, each of these
components must s elf extinguish within a specified time limit.
Furthermore, when the he lmet shell is tested, the temperature of the
lining material within the helmet that would presumably touch the
wearer's head must not exceed 70F8C.
    =20
The chin strap must also be flame resistant.  The chin strap wil l be
tested similarly to other helmet components.  It must not melt and
must self extinguish within the allowed time.20

This face shield must also withstand a flammability test.  As fo r
other components, the face shield must be self extinguishing within an
allo tted time.20 Furthermore, the face shield must not melt down
allowing the flame to reach the interior of the helmet.

Finally, this face shield must have a positive "hold down".  Since
inadvertent displacement of the face shield during racing could have
di sastrous consequences, the only way to remove or raise the face
shield from it s normal operating position must involve the deliberate
disengagement of some ca tch mechanism.  Friction mechanisms will not
satisfy this requirement.


- -------------------------------------

Ventilation and frequently, forced air ventilation, are important c
onsiderations for automotive racing.  This Standard does not limit the
diameter of ventilation holes in the helmet shell but makes specific
mention of the kinds of po rts and fittings appropriate for forced air
ventilation.

- -------------------------------------

Ventilation
     Ventilation inlets and outlets may be used provided they are made
of flexible materials such as rubber or vinyl plastic.  Ports and
fittin gs for forced air ventilation must comply with all the general
requirements on helmet features.  When connected to the forced air
sources, these ports an d fittings must not limit the range of motion
of the head and must not interfere with a quick escape from the
vehicle.

- ------------------------------------

=09<snip -- more stuff that's good>

- ------------------------------------
- -Jefrem Iwaniw, jiwaniw@domain.elided, '72 2002, '94 525i
 Keller, TX

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