Hi Dennis,

        I have been involved with this sort of thing before, but with an
Argon/Hydrogen atmosphere. We always stayed below 8% Hydrogen as above that you
will have an explosive mixture. I must agree with Ashoc on this one, the 5%
mixture would give you an extra margin of safety. In TI's Richardson facility
they did use some Hydrogen Conveyorized furnaces (built By BTU) with Nitrogen
Blanket Chambers on each end. They had no problems in general, but one of the
new furnaces was plumbed backward and upon startup, exploded. I was about 30-40
feet away at the time and this sure got my attention.

Lots of luck, but I'd stay away from a 15% Hydrogen mix.

Les Connally
>  From: [log in to unmask], on 8/17/98 1:39 PM:
>  From: Dennis J Fall@TFT on 08/17/98 01:39 PM
>
>
>  To:   [log in to unmask]
>  cc:
>  Subject:  Hydrogen/Nitrogen saftey issues
>
>  I am looking for some information regarding the safety of reflow ovens
>  using a 15% Hydrogen 85% Nitrogen atmosphere.  If anyone has had experience
>  using this concentration or something close to it, please let me know.
>  Maybe we can discuss any safety issues that may pertain to the process.
>
>  Thank You,
>
>  Dennis Fall                        P: 507-625-8445 x17
>
>  Process Engineer                   F: 507-625-3523
>
>  Thin Film Technology Corporation         mailto:[log in to unmask]
>
>  1980 Commerce Drive                http://www.thin-film.com
>
>  North Mankato, MN 56003-1702
>
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