Doc 211/24 – Hydrogen Vent Systems for Customer Applications

(Revision of Doc 211/17)

The purpose of this publication is to provide recommendations and a methodology for the safe design of venting systems for hydrogen installations and equipment located at a customer site.

The design of a hydrogen vent system aims at preventing Deflagration to Detonation Transition (DDT) and mitigating the hazards from fires, deflagration and DDT if it occures. The following scenarios are reflected:

• deflagration due to the delayed ignition of the explosive hydrogen/air mixture coming out of the vent stack;
• thermal radiation generated by the jet fire (the flame coming out of the vent stack); and
• DDT inside the vent system due to the acceleration of the combustion of the air/hydrogen mixture that can be present inside the venting system (in the presence of an ignition source). This hazard is relevant if air can enter the venting system.