Gas Supply & Pipework

What is the purpose of a gas meter?

• ADecoration only
• BTo measure gas consumption and allow billing✓
• CTo reduce gas pressure
• DNo specific purpose

Answer: Gas meters measure consumption in cubic meters for billing purposes.

What are the main components of a gas supply system?

• AJust pipes
• BMeter, regulator, pipework, safety devices, and appliances✓
• COnly the boiler
• DNo specific components

Answer: Gas supply systems include the meter, pressure regulator, pipework, and safety devices.

What is the function of a gas regulator?

• ATo increase gas pressure
• BTo maintain constant gas pressure at the correct level for appliances✓
• CTo reduce gas volume
• DTo measure gas usage

Answer: Regulators maintain stable, safe gas pressure for appliance operation.

What is the typical pressure in a domestic gas supply?

• A100 kPa
• BApproximately 21 mbar (2.1 kPa)✓
• C500 kPa
• DVariable

Answer: Domestic gas supply pressure is typically around 20-22 mbar.

What materials can be used for gas pipework in homes?

• AAny metal pipe
• BCopper, steel, or MDPE plastic (external only)✓
• CPlastic always
• DNo restrictions

Answer: Domestic gas pipes use copper, steel (often with protective coating), or MDPE plastic outside.

Why is copper preferred for gas pipework?

• ACost only
• BCorrosion resistance, durability, and ease of jointing✓
• CFor aesthetics
• DNo advantage

Answer: Copper resists corrosion, is durable, and allows reliable soldered joints.

What is the purpose of a gas isolation valve?

• ATo increase pressure
• BTo allow safe isolation of the supply for maintenance or emergency✓
• CTo measure gas flow
• DFor decoration

Answer: Isolation valves allow safe disconnection of gas for repairs or emergencies.

Where should an isolation valve be located?

• AAnywhere on the pipe
• BAt the meter for the whole supply, and before each appliance✓
• COnly outdoors
• DOnly at the boiler

Answer: Isolation valves should be at the meter and upstream of each appliance for safety.

What is pipe sizing based on?

• AJust the length
• BGas pressure, flow rate, and allowable pressure drop✓
• CCost only
• DAppearance

Answer: Pipe sizes are calculated based on pressure, flow demand, and acceptable pressure loss.

What is the purpose of a gas pressure test?

• AJust an inspection
• BTo verify pipework integrity and ensure no leakage✓
• CTo increase pressure
• DNot important

Answer: Pressure testing verifies the integrity of the entire gas system.

What is a typical gas pressure test procedure?

• AVisual inspection only
• BApplying air or inert gas at specific pressure and monitoring for pressure loss✓
• CUsing water
• DNot standardized

Answer: Pressure tests apply air (or inert gas) and measure any pressure loss over time.

What is a tightness test for gas systems?

• AChecking if connections are tight
• BA smoke test to detect gas leaks at joints and connections✓
• CPressure testing
• DNot performed

Answer: Tightness testing uses a smoke tracer to find gas leaks at connections.