1. What is PSIG to PSIA Conversion?

PSIG (pounds per square inch gauge) measures pressure relative to atmospheric pressure, while PSIA (pounds per square inch absolute) measures pressure relative to a perfect vacuum. The conversion accounts for standard atmospheric pressure (14.7 psi at sea level).

2. How Does the Calculator Work?

The calculator uses the simple conversion formula:

Where:

• \( PSIG \) — Gauge pressure (relative to atmospheric)
• \( 14.7 \) — Standard atmospheric pressure at sea level (psi)

Explanation: Absolute pressure equals gauge pressure plus atmospheric pressure.

3. Importance of Pressure Conversion

Details: Accurate pressure conversion is crucial for engineering calculations, fluid dynamics, and systems where absolute pressure matters (like HVAC, aerospace, and thermodynamics).

4. Using the Calculator

Tips: Enter PSIG value (can be positive or negative for vacuum). The calculator adds 14.7 psi to convert to absolute pressure.

5. Frequently Asked Questions (FAQ)

Q1: Why is atmospheric pressure 14.7 psi?
A: This is the average atmospheric pressure at sea level on Earth, though it varies slightly with weather and altitude.

Q2: Does this conversion work at high altitudes?
A: No, at higher altitudes you should use the local atmospheric pressure instead of 14.7 psi.

Q3: What's the difference between PSI and PSIG?
A: Often used interchangeably, but technically PSI refers to absolute pressure while PSIG specifically means gauge pressure.

Q4: How do you convert negative PSIG values?
A: Negative PSIG (vacuum) values still add 14.7, resulting in PSIA values between 0 and 14.7.

Q5: When is absolute pressure important?
A: In gas laws (PV=nRT), thermodynamics, and any system where the absolute pressure affects the process.