Psi Vs Psig Calculator

Pressure Conversion Formula:

\[ PSIA = PSIG + 14.7 \text{ (at sea level)} \]

Absolute Pressure (PSIA):

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1. What is PSI vs PSIG?

PSI (Pounds per Square Inch) is a unit of pressure, while PSIG (Pounds per Square Inch Gauge) measures pressure relative to atmospheric pressure. PSIA (Pounds per Square Inch Absolute) measures pressure relative to a perfect vacuum.

2. How Does the Calculator Work?

The calculator uses the pressure conversion formula:

\[ PSIA = PSIG + 14.7 \text{ (at sea level)} \]

Where:

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

Explanation: This formula converts gauge pressure (relative to atmospheric pressure) to absolute pressure (relative to perfect vacuum).

3. Importance of Pressure Conversion

Details: Understanding the difference between absolute and gauge pressure is crucial in various engineering applications, including HVAC systems, pneumatic controls, hydraulic systems, and industrial processes where accurate pressure measurements are essential.

4. Using the Calculator

Tips: Enter the gauge pressure value in PSIG. The calculator will automatically compute the corresponding absolute pressure in PSIA using the standard atmospheric pressure of 14.7 psi at sea level.

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between PSI, PSIG, and PSIA?
A: PSI is the general unit, PSIG is gauge pressure (relative to atmospheric), and PSIA is absolute pressure (relative to vacuum).

Q2: Why is 14.7 psi used in the calculation?
A: This represents standard atmospheric pressure at sea level. Actual atmospheric pressure varies with altitude and weather conditions.

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

Q4: Does altitude affect the conversion?
A: Yes, atmospheric pressure decreases with altitude. At higher elevations, the conversion factor would be less than 14.7 psi.

Q5: Can this calculator be used for negative gauge pressures?
A: Yes, the calculator works for vacuum pressures (negative PSIG values) as well.