1. What is PSIA to PSIG Conversion?

Definition: This calculator converts absolute pressure (PSIA) to gauge pressure (PSIG) by subtracting atmospheric pressure.

Purpose: It helps engineers, technicians, and students work with pressure measurements in different systems.

2. How Does the Conversion Work?

The calculator uses the formula:

Where:

• \( PSIG \) — Gauge pressure (psig)
• \( PSIA \) — Absolute pressure (psia)
• \( 14.7 \) — Standard atmospheric pressure at sea level (psi)

Explanation: Gauge pressure measures pressure relative to atmospheric pressure, while absolute pressure includes atmospheric pressure.

3. Importance of Pressure Conversion

Details: Proper conversion ensures accurate pressure measurements in systems like HVAC, pneumatic controls, and industrial processes.

4. Using the Calculator

Tips: Enter the absolute pressure in PSIA. The calculator will subtract standard atmospheric pressure (14.7 psi) to give PSIG.

5. Frequently Asked Questions (FAQ)

Q1: Why 14.7 psi specifically?
A: This is standard atmospheric pressure at sea level. Actual atmospheric pressure varies with altitude and weather.

Q2: Can PSIG be negative?
A: Yes, when PSIA is less than 14.7, indicating a vacuum or pressure below atmospheric.

Q3: When would I use PSIA vs PSIG?
A: PSIA is used in scientific calculations, while PSIG is common in industrial gauges and controls.

Q4: Does temperature affect the conversion?
A: The 14.7 psi standard is for 59°F (15°C). For precise work at different temperatures, adjustments may be needed.

Q5: How does altitude affect this conversion?
A: At higher altitudes, atmospheric pressure is lower than 14.7 psi, so the conversion factor should be adjusted.