Gas pressure

[cme]

I have gas fired equipment operating at 7-11" wg and I sized the pipe for 1/2 psig pressure drop. My question is what is one pound of gas equal to in inches wg? There is a regulator on the downstream pipe of the gas meter.

 

[pablo02]

inches wg refers to inches water gauge -- and I am assuming that you mean psi (pounds per sq in) when refering to a pound of gas: use the standard formula 1" H20 = 0.5781 psi (when estimating I usually use a rule of thumb that 1" H20 is roughly equivalent to ½ psi -- recognizing that it is only a very rough estimate)

to answer your question: 1 psig = 1.7298 "H2O

 

[Accystan]

With all due respect I think that pablo02 is mistaken.
1" psig does not equal 1.7298" H2O. 1 foot (12 inches) very approximately) is equal to 1 psig

1 psig is equal to 27.7" of water.

put another way

1" of water equals 0.0361 psig.

You can make these conversions very easily by remembering 4 numbers. Taking standard atmospheric pressure as the datum:

1 atmoshpere = 14.7 psig
1 atmosphere = 407" H2O
1 atmosphere = 30" of mercury
1 atmosphere = 101,325 Pascals or bars

therefore 1psig = 407/14.7 = 27.69" H2O

 

[pablo02]

I agree in concept -- I should have left off the "g", my error (or added 'wg' to my answer) -- however, the question dealt with inches water gauge which is also a measurement above atmopheric pressure therefor the value is still valid if you disregard my error in units...

 

[pablo02]

With all due respect,Accystan is correct -- I have used the wrong conversion factor (ounces/sq.in.)

My error -- glad that Accystan was watching -- as he points out the correct factor is 1" H2O = 0.0361 psi

(and my rule of thumb deals with inches Hg, not inches H2O)

My apoplogies...

 

[Accystan]

No problem pablo02. Pretty good for an electrical guy.

Now. How many electrons are there in a cubic ohm.......?

Cheers

 

[imok2]

Now. How many electrons are there in a cubic ohm.......?

There are 2 in a cu ohm ...but if you let them out they become 8 because they are cubic ohms....I think!

 

[Combustor1]

1 psig = 27.72 inches WC

 

[wilg]

0.5 inches water gage = 0.5 / 27.72 or
0.0180375 psi

 

[wilg]

1/2 psig = 27.72 / 2 = 13.86 inches water gage

 

[lilliput1]

I remember 1 cubic feet of water as weighing 62.34 lb

Therefore pressure excerted by a ft ht of water per sq in = 62.34/144 = 0.4329 psi

height of water column corresponding to 1 psi therefore = 1/.4329 = 2.31 ft = 27.72"