Keele University and Cadent are responsible for managing gas leaks on their networks. Within homes, qualified gas fitters are trained to ensure that pipework is installed properly and without leaks. There are also a number of important safety measures in place to detect leaks.
Natural gas is given a distinctive smell. This means that members of the public and gas operatives are able to detect gas even at very low levels and report it so that a leak can be repaired. Adding some hydrogen to natural gas will dilute the smell, but will not change its effectiveness. If required, additional odorant will be added to compensate for this. Tests will be carried out on the Keele network to ensure the required levels are maintained through the trial so leaks can be detected in the same way they are with just natural gas.
On the network, routine leak detection using specialist equipment which is very sensitive to natural gas. When a landlord undertakes a gas safety check in a home, this includes a leak test. For HyDeploy, all the equipment and procedures used for leak detection on the network will be thoroughly tested to make sure they work as effectively with the blend as they do with just natural gas. During the gas safety checks all the pipework in the buildings will also be leak tested.
Specific risks around gas leakage and behaviour are being assessed and carefully managed as part of HyDeploy. These include:-
- The majority of leaks occur at joints and connections, and such a leak would occur for natural gas or a blend. Although the flow rate from a leak for a blend is likely to be slightly higher than natural gas, the lower energy density means that amount of energy released is similar. In the open, the lower density and higher diffusion is also likely to aid dispersion in the event of a leak. As part of HyDeploy, analytical modelling of these phenomena is being undertaken.
- Very low levels of permeation of gases occurs through materials such as plastic pipes. Even though hydrogen will permeate more than natural gas, the rates are still lower than the regulated safety levels for leak tightness testing in buildings.
During the HyDeploy gas safety checks all the pipework in the buildings will be leak tested on natural gas and then on the blend. This will allow us to carry out any necessary repairs; and means that the installations may well be even safer than today.
Only if the HSE is satisfied that all of these issues are safely managed, will permission be granted to proceed to a live trial.