CCN1 Gas Emergency Procedures

Question 1

What is the national gas emergency telephone number in Great Britain?

Accepted Answer

0800 111 999

Answer

999

Answer

0345 850 3025

Answer

0800 023 1110

Question 2

What is the correct immediate action if a gas smell is detected in a property?

Accepted Answer

Do not operate any switches, open windows and doors, turn off the gas at the meter if safe, get everyone out, and call 0800 111 999

Answer

Open windows only and call the landlord

Answer

Turn on extraction fans to clear the gas

Answer

Turn off appliances at their own controls and wait 30 minutes

Question 3

Why must electrical switches NOT be operated when a gas escape is suspected?

Accepted Answer

Electrical switches create sparks that can ignite the gas-air mixture, causing an explosion or fire

Answer

Switches are gas-operated and will increase the flow

Answer

Switches can interfere with the gas meter's safety shut-off

Answer

Switches emit RF signals that affect gas sensors

Question 4

At what concentration in air does natural gas become explosive?

Accepted Answer

Between 5% and 15% gas in air (the Lower Explosive Limit and Upper Explosive Limit)

Answer

At any detectable concentration

Answer

Only above 50% concentration

Answer

Only below 2% concentration

Question 5

What is an 'Emergency Control Valve' (ECV) in a domestic gas installation?

Accepted Answer

The isolation valve at or near the gas meter that can shut off the entire gas supply to the property in an emergency

Answer

The valve on an individual gas appliance

Answer

A valve operated remotely by the gas transporter

Answer

The valve between the meter and the service pipe

Question 6

After a gas escape has been confirmed and the supply turned off, when may the gas supply be restored?

Accepted Answer

Only after the source of the escape has been identified and repaired by a Gas Safe Registered engineer, and a tightness test confirms the installation is gas-tight

Answer

After 30 minutes to allow gas to disperse

Answer

Immediately if the smell has cleared

Answer

As soon as the occupant requests it