Paul

Am not a toxicologist, but I understand that the organobromides are loosely crosslinked
into the epoxy and that they function by releasing hydrogen bromide and some other
nasties on heating beyond about 350°C. This HBr is the actual extinguishing agent. HBr
is decidedly very toxic and corrosive. Most organobromides are more or less toxic and
environmentally unfriendly. Some of the other released compounds may also be
ozone-depleting. However the quantities are relatively small.

FR-4 without the organobromides is called G-10 and supports continuous combustion in
air. It also produces toxic vapours, although less so and, of course, no
organobromides.

Brian

Paul Klasek wrote:

> Could you fellows enlighten me on toxicity of this additives please ,
> and what goes into "standard" FR4 ?
>
> Debate circulates about what harm can charring board do in a ventilator :
> With or without retardant :
> How far is the standard glass laminate prone to ignition/combustion/char and
>
> what would be the effects of toxins generated ?
>
> Thanks a lot
>
> Paul Klasek
> http://www.resmed.com
>
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