PSIG Formula:
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Definition: This calculator converts absolute pressure (PSI) to gauge pressure (PSIG) by subtracting atmospheric pressure.
Purpose: It helps engineers, technicians, and mechanics work with pressure measurements in various systems.
The calculator uses the formula:
Where:
Explanation: Gauge pressure represents pressure relative to atmospheric pressure, while absolute pressure includes atmospheric pressure.
Details: Proper pressure measurement is critical for system safety, performance monitoring, and equipment specifications.
Tips: Enter the absolute pressure in PSI. The calculator will subtract standard atmospheric pressure (14.7 psi) to give you gauge pressure.
Q1: What's the difference between PSI and PSIG?
A: PSI (absolute) measures pressure relative to a perfect vacuum, while PSIG measures pressure relative to atmospheric pressure.
Q2: Why subtract 14.7 psi?
A: This accounts for standard atmospheric pressure at sea level (1 atmosphere).
Q3: When would PSIG be negative?
A: When absolute pressure is less than atmospheric pressure (vacuum conditions).
Q4: Does altitude affect this calculation?
A: Yes, atmospheric pressure decreases with altitude. For precise measurements at high altitudes, adjust the 14.7 value accordingly.
Q5: What instruments typically show PSIG?
A: Most pressure gauges (tire gauges, boiler gauges, etc.) display PSIG as they measure pressure relative to ambient.