Re: A/C on fire

Date:         20 Nov 98 02:30:39 
From:         k_ish <kenish@ix.netcom.com>
Organization: ICGNetcom
References:   1 2
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Ron Parsons wrote:
> For what it's worth, aircraft are constructed of two main ingredients,
> aluminum and PVC (polyvinylchloride). When PVC burns, it gives off
> chlorine gas, which was one of the gases banned for further warfare use
> after WWI.
>
> Flight crews are provided with smoke hoods these days and they are even
> available commercially for individuals, but so far not required equipment
> for passengers.
>
> The smell you are familiar with as electrical smoke, is overheated PVC
> used as insulation on the wiring. Virtually the entire cabin interior is
> constructed from PVC materials.

Correct, decades ago.  Turbine transports have requirements for
flammability, as well as smoke and toxicity.  This affects all
non-metallic materials aboard the aircraft.  The latest generation of
airliners (747-400, A340, 767, 757, MD-11, 777 etc). do not have any
PVC.  Wiring is materials such as Teflon and Tefzel; cabin walls,
luggage bins, etc. are made of carbon fiber and other composites.
Carpeting, upholstery, wallpaper, etc. are also low-flammability.  The
only items that can be made of PVC are very small grommets, latches, and
hardware- categorized under "small exempt".  FAR 25.853 addresses all of
this; the airframe manufacturers have standards that exceed the FARs.

Older aircraft such as the 707, DC-8, 727, etc. originally had PVC
wiring.  Generally speaking, any items replaced (which would be most of
it on a plane that old) would be with better materials.

Ken Ishiguro