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PSIA to PSIG Conversion Formula:
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The PSIA to PSIG conversion calculates gauge pressure from absolute pressure by subtracting standard atmospheric pressure (14.7 psi). PSIA represents absolute pressure relative to perfect vacuum, while PSIG represents pressure relative to atmospheric pressure.
The calculator uses the conversion formula:
Where:
Explanation: This conversion accounts for the fact that gauge pressure measurements are referenced to atmospheric pressure, while absolute pressure includes atmospheric pressure.
Details: Accurate pressure conversion is crucial for engineering applications, industrial processes, HVAC systems, and pneumatic controls where pressure measurements must be properly interpreted for system design and operation.
Tips: Enter absolute pressure (PSIA) in pounds per square inch. The value must be greater than 0. The calculator will automatically subtract standard atmospheric pressure to provide the gauge pressure reading.
Q1: What is the difference between PSIA and PSIG?
A: PSIA measures pressure relative to absolute vacuum, while PSIG measures pressure relative to atmospheric pressure. PSIG = PSIA - atmospheric pressure.
Q2: Why is 14.7 psi used for atmospheric pressure?
A: 14.7 psi represents standard atmospheric pressure at sea level. Actual atmospheric pressure varies with altitude and weather conditions.
Q3: Can PSIG be negative?
A: Yes, PSIG can be negative when the absolute pressure is less than atmospheric pressure, indicating vacuum conditions.
Q4: When should I use PSIA vs PSIG?
A: Use PSIA for scientific calculations and absolute pressure systems. Use PSIG for most industrial and mechanical applications where pressure relative to atmosphere is relevant.
Q5: How does altitude affect this conversion?
A: At higher altitudes, atmospheric pressure decreases, so the conversion factor would be less than 14.7 psi. This calculator uses standard sea-level atmospheric pressure.