A compound gauge reading of 10 inches of mercury (Hg) is equivalent to how many pounds absolute?

To determine the equivalent in pounds absolute for a compound gauge reading of 10 inches of mercury (Hg), it is important to understand the relationship between inches of mercury and pressure in psi (pounds per square inch). The conversion factor typically used is that 1 inch of mercury is approximately equal to 0.491 psi.

Multiplying the reading of 10 inches of mercury by the conversion factor (0.491 psi per inch of Hg) gives us:

10 inches of Hg × 0.491 PSI/inch of Hg = 4.91 PSIA.

Since PSIA refers to pounds per square inch absolute, it’s common to round this figure when calculating. Rounding 4.91 to the nearest whole number gives us approximately 5 PSIA.

Thus, the reading of 10 inches of mercury is equivalent to about 5 PSIA, making this the correct answer. Understanding this conversion is crucial for operators, as it helps maintain accurate pressure measurements essential for a variety of engineering applications.