Inches_of_Mercury
Inch of mercury
Measurement unit for pressure
Inch of mercury (inHg and ″Hg) is a non-SI unit of measurement for pressure. It is used for barometric pressure in weather reports, refrigeration and aviation in the United States.
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It is the pressure exerted by a column of mercury 1 inch (25.4 mm) in height at the standard acceleration of gravity. Conversion to metric units depends on the density of mercury, and hence its temperature; typical conversion factors are:[1]
In older literature, an "inch of mercury" is based on the height of a column of mercury at 60 °F (15.6 °C).[1]
- 1 inHg60 °F = 3,376.85 pascals (33.7685 hPa)
In Imperial units: 1 inHg60 °F = 0.489 771 psi, or 2.041 771 inHg60 °F = 1 psi.