Backflow Prevention Assembly Tester — Practice Exam
Hydraulics: practice questions
Our Backflow Tester bank has 18 questions on this topic. Here are 4 of them with answers; the full mock exam draws from every topic, like the real one.
Question 1
How much pressure does a 1-foot column of water exert?
- About 0.433 psi
- About 14.7 psi
- About 1.5 psi per foot
- About 2.31 psi
Show the answer
A. About 0.433 psi — 1 psi lifts water about 2.31 feet.
Question 2
What is atmospheric pressure at sea level, approximately?
- 14.7 psi
- 100 psi
- About 1.0 psi
- 1 psi
Show the answer
A. 14.7 psi — A perfect vacuum is 0 psia.
Question 3
What is gauge pressure?
- Pressure measured from a perfect vacuum, so it always reads 14.7 psi higher than a gauge
- Pressure only when water is flowing
- Pressure measured relative to atmospheric pressure (psig)
- Pressure measured relative to a perfect vacuum
Show the answer
C. Pressure measured relative to atmospheric pressure (psig) — Absolute pressure = gauge + atmospheric.
Question 4
A building's top floor is 46 feet above the meter. About how much pressure is lost to elevation?
- About 20 psi
- About 46 psi
- About 106 psi
- About 10 psi
Show the answer
A. About 20 psi — 46 × 0.433 ≈ 19.9 psi.