Understanding Pressure Measurements

The video tutorial discusses the concept of pressure, focusing on PSI, PSIA, and PSIG. It explains how pressure is measured in HVACR systems, using infographics to illustrate the relationship between different pressure units. The tutorial covers atmospheric pressure, its measurement using barometers, and how tire gauges are calibrated to read zero at atmospheric pressure. It also explains the concept of vacuum and the difference between absolute and gauge pressure, emphasizing the importance of using absolute pressures in calculating compression ratios in HVACR applications.

What does PSI stand for in the context of pressure measurement?

• Pressure per square meter

• Pounds per square inch

• Pounds per square meter

• Pressure per square inch

Which device is typically used to measure atmospheric pressure?

• Barometer

• Tire gauge

• Thermometer

• Hygrometer

What do tire gauges read when exposed to atmospheric pressure?

• 50 PSI

• 0 PSI

• 100 PSI

• 14.7 PSI

What is considered a vacuum in terms of pressure?

• Pressure below 14.7 PSI

• Pressure at 14.7 PSI

• Pressure above 14.7 PSI

• Pressure at 0 PSI

How is pressure below atmospheric pressure usually measured?

• Inches of mercury vacuum

• Inches of water

• PSIA

• PSIG

What is the reference point for gauge pressure?

• Vacuum

• Atmospheric pressure

• Sea level

• Absolute zero

What is the gauge pressure if the absolute pressure is 114.7 PSIA?

• 0 PSIG

• 114.7 PSIG

• 100 PSIG

• 14.7 PSIG

In HVACR, when calculating compression ratios, which type of pressure is used?

• Static pressure

• Absolute pressure

• Gauge pressure

• Differential pressure

What is the atmospheric pressure at sea level in PSIA?

• 0 PSIA

• 50 PSIA

• 14.7 PSIA

• 100 PSIA

Why does atmospheric pressure decrease as you go higher in the atmosphere?

• Because the air is denser

• Because there is less air above to provide weight

• Because the temperature increases

• Because the air is more humid