3102 Predictions of minimum spark ignition energy and quenching distances for CH4/H2 and C3H8/H2 mixtures with air

Overview:

This report was commissioned to determine the point when gas streams containing hydrogen as a component should be treated as hydrogen for the purposes of specifying electrical equipment.

It has long been recognised that the particular properties of hydrogen require very specialised electrical equipment to be used to prevent ignitions. Many industrial gas streams contain hydrogen mixed with hydrocarbon gases. Engineers have to decide whether equipment designed for hydrogen duty is needed (i.e. gas group IIC) or whether equipment designed to the less stringent standards for hydrocarbon gas groups IIA or IIB is suitable.

This report provides the justification for the cut-off value of hydrogen concentration used when specifying hydrogen certified equipment (gas group IIC) for gas mixtures, referenced in the EI Model Code of Safe Practice Part 15: Area classification code for installations handling flammable fluids.