Purge Time Calculator

| Added in Physics

What is Purge Time and Why Should You Care?

Purge Time is the duration required to purge a gas piping system. Knowing the precise purge time ensures you maintain safety standards, optimize efficiency, and effectively plan maintenance schedules. Without this information, you risk an incomplete purge, which is a safety hazard.

How to Calculate Purge Time

Imperial Units Formula

[PT = \frac{\pi \times \text{pipe diameter (in)} \times \text{length (ft)}}{12 \times \text{purge rate (cfh)}} \times 60]

Where:

  • PT is the Purge Time (minutes)
  • Pipe diameter is in inches
  • Pipe length is in feet
  • Purge rate is in cubic feet per hour (cfh)

Metric Units Formula

[PT = \frac{\pi \times \text{pipe diameter (cm)} \times \text{length (m)}}{\text{purge rate (m}^3\text{/hr)}} \times 60]

Where:

  • PT is the Purge Time (minutes)
  • Pipe diameter is in centimeters
  • Pipe length is in meters
  • Purge rate is in cubic meters per hour

Calculation Example

Given:

  • Pipe diameter: 6 inches
  • Pipe length: 200 feet
  • Purge rate: 5 cfh

Calculation:

[PT = \frac{\pi \times 6 \times 200}{12 \times 5} \times 60]

Step by step:

  1. [\pi \times 6 = 18.85]
  2. [18.85 \times 200 = 3770]
  3. [\frac{3770}{60} = 62.83]
  4. [62.83 \times 60 = 3770 \text{ minutes}]

The Purge Time is approximately 3770 minutes. Safety first, efficiency second!

Frequently Asked Questions

Purge time is the duration required to completely replace the gas in a piping system with a purge gas, typically for safety or maintenance purposes.

Accurate purge time calculation ensures safety standards are met, optimizes efficiency, and helps effectively plan maintenance schedules. An incomplete purge can be a safety hazard.

Purge time depends on pipe diameter, pipe length, and purge rate. Larger diameter or longer pipes require more time; higher purge rates reduce the time needed.

For imperial units: PT = (Pi x Diameter (in) x Length (ft)) / (12 x Purge Rate (cfh)) x 60. The result is in minutes.