An oldie-but-goodie, via Meryl:

Couple years ago, some people I worked with finally completed a long-delayed project to build a very large vacuum chamber for testing plasma thrusters and other advanced spacecraft propulsion systems.  Not the biggest in the business, but maybe top ten nationwide.  Big enough to walk around inside, at any rate, which is the important point.

Important, because in order to go operational it needed the approval of the local Safety Nazis.  You know the type.  They have a checklist, nay, a whole handbook of checklists, one of which involves Confined Spaces.  Big enough to walk around in?  Check.  Airtight?  Check. Can be filled with asphyxiant gas?  Well, the MSDS for “Vacuum” apparently lists it as an “asphyxiant”, so check.  It’s a Confined Space, and so the Confined Space checklist must be implemented.

Issue the first:  How do they make certain nobody can accidentally walk in while the chamber is full of that deadly asphyxiant, “vacuum”?  No, the fifty *tons* of force holding the door closed, is not an acceptable answer.

Issue the second:  When the chamber is vented back to full atmospheric pressure, where does the vacuum go?  If the chamber were accidentally vented by opening the door (see above, and note exact Safety Nazi quote, “OK, say if you were Superman and you opened the door”), where would the vacuum go?

Issue the third:  What assurance is there, that when the chamber is vented back to full atmosphere, there is an adequate percentage of oxygen in the chamber?  Hint: It is a big, big, big mistake here to acknowledge here that the laws of statistical gas dynamics allow for one chance in 10^10^17 (no typo) that the chamber will spontaneously refill with a sufficiently oxygen-poor atmosphere to preclude respiration.

Issue the forth, and so help me God I am not making this up, again an exact Safety Nazi quote, “How can you be sure there won’t be vacuum pockets left in the chamber, that someone could accidentally stick their head into?”

And, coupled with issue #2, there could be deadly vacuum pockets floating around the lab!  Aieeee!!!!  Run for your lives!

It only took three weeks to find someone with the common sense and the real authority to overrule the Safety Nazis on this one, and the SNs still take offense if anyone brings it up in their presence.

Vacuum pockets. - John Schilling

Posted by: Old Grouch in In Passing at 23:41:39 GMT | No Comments | Add Comment
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