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On Tue, Oct 16, 2007 at 11:57:46AM -0600, Nate Duehr wrote:
> Alan B. Pearce wrote:
> >> An intrinsically safe system does what it does by sticking to
> >> that part of the laws of physics that make sparks impossible.
> > 
> > or encloses them in a way that will not allow the spark to reach the outside 
> > environment.
> 
> Yep, this is typically how the 2-way radio world's "intrinsically safe" 
> products work also... push-to-talk and other open contacts are 
> surrounded by rubber and sealed.

But wouldn't that only work if the radio was actually hermetically
sealed? If it wasn't, the explosive atmosphere could seep in anyway.

I thought the idea was that explosive safe products are often simply
designed so that they can *contain* an internal explosion, rather than
trying to prevent the atmosphere from getting in.

Of course, intrinsically safe, IE no spark can form in the first place,
is another matter.

- -- 
http://petertodd.org
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