On 02/27/2016 12:48 AM, OFWW wrote:
On Fri, 26 Feb 2016 19:59:32 -0500, wrote:
....

I questioned it because you said it and it was repeated. I didn't
know if you were talking about in.Hg, or what. Yes, PSI is half in.Hg
(though I hadn't thought of it that way) by the simple fact that
1ATM = ~14PSI = ~30"Hg.

1ATM = 14 PSI = 0" Hg

You've mixed reference -- 1 atm is ~760 mm Hg (29.9"), 0" Hg _gauge_
pressure relative to atmospheric. Negative is then vacuum, positive is
pressure like 28 psi for tires is 28 psig(auge) or 28 psi _above_
atmospheric.

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