1. What Is PSIG?

PSIG (Pounds per Square Inch Gauge) is the pressure measured relative to atmospheric pressure. It represents the pressure above or below the ambient atmospheric pressure and is commonly used in industrial, automotive, and HVAC applications.

2. How Does The Calculator Work?

The calculator uses the PSIG calculation formula:

Where:

• \( PSIA \) — Absolute pressure in pounds per square inch
• \( Atmospheric\ Pressure \) — Standard atmospheric pressure (typically 14.7 psi at sea level)

Explanation: Gauge pressure represents the difference between absolute pressure and atmospheric pressure. Positive PSIG indicates pressure above atmospheric, while negative PSIG indicates vacuum or pressure below atmospheric.

3. Importance Of PSIG Calculation

Details: Accurate PSIG calculation is essential for pressure measurement in various systems including pneumatic controls, hydraulic systems, tire pressure monitoring, and industrial process control where gauge pressure readings are standard.

4. Using The Calculator

Tips: Enter absolute pressure (PSIA) and atmospheric pressure (default is 14.7 psi for sea level). All values must be positive numbers. Atmospheric pressure may vary with altitude and weather conditions.

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between PSIG and PSIA?
A: PSIG is gauge pressure relative to atmospheric pressure, while PSIA is absolute pressure relative to perfect vacuum. PSIA = PSIG + Atmospheric Pressure.

Q2: Why is atmospheric pressure typically 14.7 psi?
A: 14.7 psi represents standard atmospheric pressure at sea level. Actual atmospheric pressure varies with altitude, temperature, and weather conditions.

Q3: When should I use PSIG vs PSIA?
A: Use PSIG for most industrial and mechanical applications (tire pressure, hydraulic systems). Use PSIA for scientific calculations, vacuum systems, and when absolute pressure reference is required.

Q4: How does altitude affect PSIG readings?
A: At higher altitudes, atmospheric pressure decreases, so the same absolute pressure will show a higher PSIG reading compared to sea level.

Q5: Can PSIG be negative?
A: Yes, negative PSIG indicates vacuum or pressure below atmospheric pressure, commonly referred to as inches of mercury (inHg) or other vacuum units.