1. What is PSI to PSIG Conversion?

PSIG (pounds per square inch gauge) is the pressure measured relative to atmospheric pressure, while PSI (pounds per square inch absolute) is the pressure measured relative to a perfect vacuum. The conversion between them accounts for standard atmospheric pressure (14.7 psi at sea level).

2. How Does the Calculator Work?

The calculator uses the simple equation:

Where:

• \( PSI \) — Absolute pressure in pounds per square inch
• \( 14.7 \) — Standard atmospheric pressure at sea level (psi)

Explanation: This conversion subtracts atmospheric pressure to give gauge pressure, which is what most pressure gauges display.

3. Importance of PSIG Calculation

Details: Understanding the difference between absolute and gauge pressure is crucial in engineering, HVAC systems, pneumatic tools, and many industrial applications where pressure measurements are critical.

4. Using the Calculator

Tips: Enter the absolute pressure in PSI. The calculator will automatically subtract atmospheric pressure (14.7 psi) to give you the gauge pressure (PSIG).

5. Frequently Asked Questions (FAQ)

Q1: Why subtract 14.7 psi?
A: This accounts for standard atmospheric pressure at sea level. Gauge pressure measures pressure above atmospheric.

Q2: Does this value change with altitude?
A: Yes, atmospheric pressure decreases with altitude. At higher elevations, the subtraction factor would be less than 14.7 psi.

Q3: What's the difference between PSI and PSIG?
A: PSI is absolute pressure (including atmospheric), while PSIG is gauge pressure (excluding atmospheric).

Q4: When would I need to make this conversion?
A: When working with systems that use absolute pressure measurements but need gauge pressure values, or when comparing measurements from different types of pressure sensors.

Q5: Can PSIG be negative?
A: Yes, negative PSIG indicates a vacuum (pressure below atmospheric).