barg vs mbara & psia
by png on 08/07/03 at 08:11:09

Anyone know the conversion from bar gauge (barg) to millibar absolute (mbara)?  Is it the same a going from psig to psia?  I am actually trying to convert from psig to millibar absolute and was told there was something funny about the conversion factor.

Thanks.

Re: barg vs mbara & psia
by Robert Fogt on 08/07/03 at 11:34:51

The term gauge means the measurement is read from a guage which is actually measureing the difference between atmospheric pressure and the pressure of the gas.

The term absolute means you are measuring the pressure of the gas, Plus the atmospheric pressure.

At sea level, the air pressure is 0 bar gauge, or 1.01325 bar absolute.

Basically, to convert from absolute to gauge, just subtract the atmospheric pressure. To convert from gauge to absolute, add atmospheric pressure.

1 atmosphere = 14.50378 PSI = 1.01325 bar

Re: barg vs mbara & psia
by png on 08/07/03 at 13:06:58

Thank you for the confirmation.  I thought the same convention would apply, just like psig and psia.  After all, absolute pressure is absolute pressure.  Since mbar is more of a European standard, I wasn't sure whether there was anything subtle on the conversion.  Also, I guess mbar is typically reported in absolute anyway.  However, I have seen difference convention where people have put an a at the end for absolute.

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