Gauge Pressure
Objectives Describe gauge pressure. Correctly calculate the gauge pressure for a given depth of either fresh or salt water. Apply the concept of gauge pressure to scuba.
Main Points Gauge pressure Calculating gauge pressure Application to scuba
Description Uses atmospheric pressure as zero.
Example 1 Calculate gauge pressure at 57' of fresh water. Answer: (.432psi/ft) x 57' = 24.6 psig Convert the answer above to absolute pressure. Answer: 24.6psi psi = 39.3psia
Example 2 Calculate gauge pressure at 57' of salt water. Answer: (.445psi/ft) x 57' = psig Convert the answer above to absolute pressure. Answer: psi psi = psia
Application to Scuba The concept of gauge pressure explains why an analog depth gauge will not give an accurate reading of depth when diving at altitude. Care to explain? –An analog depth gauge uses 14.7 psi as 0 ft – at altitude you must dive to some depth before you reach a pressure of 14.7 psi
Main Points Gauge pressure Calculating gauge pressure Application to scuba
Objectives Describe gauge pressure. Correctly calculate the gauge pressure for a given depth of either fresh or salt water. Apply the concept of gauge pressure to scuba.