How much ventilation would a hydrogen compressor enclosure need in California, assuming European solutions are similar to the California regulations? The desire is to keep all electrical nonclassified while being in a class 1 div 2 container by flowing enough fresh air to keep the lower flammable limit below 25%. The project uses a 20 ft container.

The regulations for electrical classification in Europe and a US jurisdiction such as California are significantly different and should not be assumed to be the same. Consultation with Authorities Having Jurisdiction or a Third- Party expert regarding the application of the US National Electric Code is advised. Some additional important points:

The HSP has concerns with the use of ventilation to provide an option to the required electrical classification. The Panel does not advocate for unclassified equipment in the described area. It is a major challenge to achieve the response time required to sense and implement emergency ventilation from continuous ventilation required to cope with internal leakage. While the leak may be small, it might also be large and overwhelm almost any ventilation rate.

The space inside the container should be classified, and electrical equipment in the container should be Class 1, Div 2. Otherwise consider putting the electrical equipment outside the container.