1. What is Velocity Pressure?

Velocity Pressure (VP) is the pressure required to accelerate air from zero velocity to some velocity (V) and is proportional to the kinetic energy of the air stream. It's a fundamental concept in HVAC and fluid dynamics.

2. How Does the Calculator Work?

The calculator uses the Velocity Pressure formula:

Where:

• \( Velocity \) — Air velocity in feet per minute (fpm)
• \( 4005 \) — Constant for standard air conditions

Explanation: The formula calculates the velocity pressure based on the air velocity, with the constant 4005 derived from standard air density conditions.

3. Importance of Velocity Pressure Calculation

Details: Velocity pressure is essential for determining airflow rates in duct systems, calculating fan performance, and designing efficient ventilation systems in HVAC applications.

4. Using the Calculator

Tips: Enter velocity in feet per minute (fpm). The value must be valid (velocity > 0).

5. Frequently Asked Questions (FAQ)

Q1: What units are used for velocity pressure?
A: Velocity pressure is typically measured in inches of water gauge (in. w.g.) in imperial systems.

Q2: Why is the constant 4005 used?
A: The constant 4005 is derived from standard air density conditions (0.075 lb/ft³) and unit conversion factors.

Q3: How is velocity pressure related to total pressure?
A: Total pressure equals static pressure plus velocity pressure in a ventilation system.

Q4: Can this formula be used for any fluid?
A: This specific formula with constant 4005 is designed for standard air. Different constants would be needed for other fluids or conditions.

Q5: How accurate is this calculation?
A: The calculation is accurate for standard air conditions. For non-standard conditions, adjustments for air density may be necessary.