1. What is PSIA to PSIG Conversion?

The PSIA to PSIG conversion calculates gauge pressure from absolute pressure by subtracting atmospheric pressure at sea level (14.7 psi). PSIA represents absolute pressure relative to perfect vacuum, while PSIG represents pressure relative to atmospheric pressure.

2. How Does the Calculator Work?

The calculator uses the simple formula:

Where:

• \( PSIA \) — Absolute pressure in pounds per square inch absolute
• \( PSIG \) — Gauge pressure in pounds per square inch gauge
• \( 14.7 \) — Standard atmospheric pressure at sea level in psi

Explanation: This conversion accounts for the fact that gauge pressure measurements are zero-referenced against ambient atmospheric pressure, while absolute pressure includes atmospheric pressure.

3. Importance of Pressure Conversion

Details: Accurate pressure conversion is essential for engineering applications, industrial processes, HVAC systems, and any scenario where pressure measurements must be standardized between absolute and gauge references.

4. Using the Calculator

Tips: Enter absolute pressure (PSIA) value. The value must be greater than 0. The calculator will automatically compute the corresponding gauge pressure (PSIG).

5. Frequently Asked Questions (FAQ)

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 conversion?
A: 14.7 psi represents standard atmospheric pressure at sea level. This value may vary slightly 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 measurements. Use PSIG for most industrial and engineering applications where pressure relative to atmosphere is relevant.

Q5: Does altitude affect the conversion?
A: Yes, atmospheric pressure decreases with altitude. For precise calculations at high altitudes, use the local atmospheric pressure instead of 14.7 psi.