1. What is an in Hg Vacuum to PSI Calculator?

Definition: This calculator converts vacuum measurements in inches of mercury (in Hg) to pressure in pounds per square inch (PSI).

Purpose: It helps engineers, technicians, and scientists convert between these common pressure measurement units used in various industrial and scientific applications.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( P_{psi} \) — Pressure in pounds per square inch (PSI)
• \( inHg \) — Vacuum measurement in inches of mercury
• 29.92 — Standard atmospheric pressure in in Hg
• 0.491154 — Conversion factor from in Hg to PSI

Explanation: The formula subtracts the vacuum measurement from standard atmospheric pressure, then converts the result to PSI.

3. Importance of Pressure Unit Conversion

Details: Accurate conversion between pressure units is crucial for system design, operation, and troubleshooting in fields like HVAC, aerospace, and industrial processes.

4. Using the Calculator

Tips: Enter the vacuum measurement in inches of mercury (0 to 29.92 range). The calculator will display the equivalent pressure in PSI.

5. Frequently Asked Questions (FAQ)

Q1: Why subtract from 29.92 in Hg?
A: 29.92 in Hg represents standard atmospheric pressure. The subtraction gives the pressure difference from atmospheric.

Q2: What does 0 in Hg vacuum mean?
A: 0 in Hg vacuum means no vacuum - atmospheric pressure (0 PSI gauge pressure).

Q3: What does 29.92 in Hg vacuum mean?
A: 29.92 in Hg represents a perfect vacuum (approximately -14.7 PSI gauge pressure).

Q4: When would I need this conversion?
A: When working with systems that measure vacuum in in Hg but require PSI values for calculations or specifications.

Q5: Is this absolute or gauge pressure?
A: The result is gauge pressure (relative to atmospheric). For absolute pressure, add 14.7 PSI.