Development of Hydrogen Area Classification Data for Use in Village Trials

The natural gas industry proposes carrying out trials on limited parts of the gas network using hydrogen as an alternative to natural gas as a fuel. Ahead of these trials, it is important to establish whether the zones of negligible extent that are typically applied to natural gas systems could still be considered zones of negligible extent for hydrogen. The standard IGEM/UP/16 is commonly used by the natural gas industry to carry out area classification for low pressure gas systems, for example as found in boiler houses. However, IGEM/UP/16 is not applicable to hydrogen. Therefore, IGEM commissioned HSE’s Science Division to develop some data that could be used to feed into an area classification assessment for the village trials.
This report identifies two main elements of IGEM/UP/16 which may not apply to hydrogen and suggests values for hydrogen-specific alternatives. These are the ventilation rate requirements to allow a zone to be deemed of negligible extent and the definition of a confined space.