Gas Pipe Sizing Calculator UK

BS 6891 Standard Formula:

\[ \text{Pipe Size (mm)} = \sqrt{\frac{\text{Flow (m³/h)} \times \text{Length (m)} \times \text{SG}}{\Delta P}} \]

Flow:

m³/h

Length:

Specific Gravity (SG):

Pressure Drop (ΔP):

mbar

Pipe Size:

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1. What Is Gas Pipe Sizing?

Gas pipe sizing involves calculating the appropriate diameter of gas pipes to ensure adequate gas flow to appliances while maintaining safe pressure levels. The BS 6891 standard provides guidelines for gas installation in the UK.

2. How Does The Calculator Work?

The calculator uses the BS 6891 standard formula:

\[ \text{Pipe Size (mm)} = \sqrt{\frac{\text{Flow (m³/h)} \times \text{Length (m)} \times \text{SG}}{\Delta P}} \]

Where:

\( \text{Flow} \) — Gas flow rate in cubic meters per hour
\( \text{Length} \) — Pipe length in meters
\( \text{SG} \) — Specific gravity of the gas
\( \Delta P \) — Pressure drop in millibars

Explanation: This formula calculates the minimum pipe diameter required to deliver the specified gas flow while maintaining the allowable pressure drop.

3. Importance Of Proper Pipe Sizing

Details: Correct pipe sizing ensures efficient gas delivery, prevents pressure drops that could affect appliance performance, and maintains safety standards. Undersized pipes can cause insufficient gas supply, while oversized pipes are unnecessarily expensive.

4. Using The Calculator

Tips: Enter gas flow in m³/h, pipe length in meters, specific gravity of the gas, and allowable pressure drop in mbar. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What Is BS 6891 Standard?
A: BS 6891 is the British Standard for installation of low pressure gas pipework in domestic premises, covering design, installation, and commissioning requirements.

Q2: What Is Typical Specific Gravity For Natural Gas?
A: Natural gas typically has a specific gravity of 0.55-0.65, but always check with your gas supplier for exact values.

Q3: What Is An Acceptable Pressure Drop?
A: Typically 1 mbar pressure drop is acceptable for most domestic installations, but consult relevant standards for specific applications.

Q4: Can This Calculator Be Used For Commercial Installations?
A: While based on BS 6891 principles, commercial installations may require more complex calculations and professional engineering assessment.

Q5: Are There Other Factors To Consider In Pipe Sizing?
A: Yes, factors include number of bends, fittings, altitude, gas temperature, and future expansion requirements. Always consult a qualified gas engineer.