How is absolute pressure calculated?

• A. Atmospheric pressure minus gauge pressure
• B. Gauge pressure plus atmospheric pressure
• C. Gauge pressure only
• D. Atmospheric pressure only

Answer: (B)

Absolute pressure is calculated by adding gauge pressure to atmospheric pressure. This is important in various applications, including HVAC and refrigeration, where understanding the total pressure exerted by a gas is crucial for accurate measurements and system efficiency.

Gauge pressure measures the pressure relative to atmospheric pressure, meaning it does not take into account the atmospheric pressure itself. When this gauge pressure is combined with atmospheric pressure, it provides the absolute pressure, which is the actual pressure experienced in a system.

For instance, if the gauge pressure in a system reads 30 psi and atmospheric pressure is 14.7 psi, the absolute pressure would be 30 psi + 14.7 psi = 44.7 psi. This clarity in measurement is vital for ensuring proper system operation and compliance with safety standards in refrigeration and air conditioning systems.