Shark HNG • 9.801-195.0 • Rev. 4/14
OPERA
TOR’S MANU
AL
PRESSURE
W
ASHER
16
BASIC FACTS
PRESSURE EQUIVALENTS
Simply stated, pressure is the force exerted by a gas or liquid attempting to escape from a container. It is useful
to know how strong this “attempt to escape” is. Pressure can be measured with a manometer or with a pressure
gauge. At the lower levels, it is expressed in “water column inches” i.e. 11 w.c.i. Higher pressures are expressed
in terms of the force exerted against a square inch of area, for example, 125 lbs. per square inch (125 psi).
1 water column inch
=
50 oz./sq. in. 11 water column inches =
6.35 oz./sq. in.
11 water column inches
=
4 lb./sq. in. 1 lb./sq. in.
=
27.71 water column inches
1 lb./sq. in.
=
2.04” Mercury 1” Mercury
=
.39 lb./sq. in
1 Std. Atmosphere
=
14.73 lbs./sq. in. Capacity in cf/h
=
Btu/H (Nameplate)
Btu/cu ft (Gas Utility)
Based on 60°
Propane
Butane
1 Cu. Ft. NG Approx 1,000 Cu. Ft.
Formula
C3H8
C4H10
Vaporization Point (°F)
-43.7
31.1
Specific Gravity (Vapor)
1.522
2.006
Specific Gravity (Liquid)
0.508
0.584
Lbs. per Gal. (Liquid)
4.23
4.87
BTU per Cu. Ft. (Vapor)
2.563
3.39
BTU per Gal. (Liquid)
91.547
102.032
BTU per Lb. (Liquid)
21.591
21.221
Cu. Ft. per Lb. (Liquid)
8.607
6.53
Cu. Ft. per Gal. (Liquid)
36.45
31.8
Octane Number
125
91
Molecular Weight
44.09
58.12
To Calculate Running Cost:
1,000 BTU = 1 Cu. Ft.
100 Cu Ft. = 1 Therm
1 Therm = 1 Hour
Cost of Gas per Therm = Cost to Run
Example Using Natural Gas
at 50¢ Therm:
400,000 BTU Machine
400 Cu. Ft.
(400,000 / 1,000)
4 x 50¢ = $2.00 / Hour to Run
((400 / 100) x cost of gas)
