Gas & FuelQuestion 75 of 110
An elevated industrial gas line operates at 5 psi and is regulated down for appliances rated in inches of water column. Using 1 psi = 27.7 in water column, what is 5 psi expressed in inches of water column?
a.27.7 in w.c.
b.55.4 in w.c.
c.138.5 in w.c.
d.500 in w.c.
Explanation
Inches of water column = psi x 27.7 = 5 x 27.7 = 138.5 in w.c. Appliance regulators are commonly set near 7 in w.c. for natural gas, so an elevated 138.5 in w.c. supply must be stepped down by a line-pressure regulator with overpressure protection. Mixing up psi and inches of water column is a common and dangerous error.
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