What is the maximum height for a perfect vacuum (at sea level) to - ProProfs Discuss

# What is the maximum height for a perfect vacuum (at sea level) to raise water in a pipe?

A. 21
B. 26
C. 30
D. 34

This question is part of Backflow Quiz 5
Asked by Pbarton, Last updated: Feb 14, 2020

#### ron wallace

Ron wallace

The answer to this question is 34

#### M. Kennedy

M. Kennedy, Web Content Writer, Denver

The maximum hypothetical vacuum at sea level is 29.92 in-Hg, actual pump capabilities are based on and compared to this theoretical value. Depending upon pump design, the vacuum limit ranges from 28 to 29.5 in -Hg, or about 93% or 98% of the maximum abstract value. The vacuum level is determined by the pressure difference between the evacuated volume and the surrounding atmosphere.

Several units of measure can be used. The standard metric unit for a vacuum measurement is the millibar, or mbar. The higher up you are, the less volume you can attain. This is because free air is dense at higher altitudes, which has the effect of reducing the capacity and maximum vacuum levels.

Pbarton