It is important to distinguish between the different regulations in force since there are two types of battery technology: lead-acid and lithium ion. The Order of May 29, 2000 (Decree of May 31, 2006) relating to lead-acid batteries, which indicates that a charging room is required when the charger power exceeds 50kW of direct current power.
Now that we know when it is necessary to have a charge room, we will focus more specifically on lead-acid batteries. Indeed, the technology used in these batteries (lead plate in sulfuric acid) can generate hydrogen by chemical reaction between lead and acid. This possible hydrogen emission is mainly due to a failure of the battery casing.
It is common knowledge that lead-acid batteries release hydrogen gas that can be potentially explosive. The battery rooms must be adequately ventilated to prohibit the build-up of hydrogen gas. During normal operations, off gassing of the batteries is relatively small.
The lead battery charging premises are subject to regulations relating to the decree of 29 May 2000 for installations classified for environmental protection (ICPE). These installations are subject to declaration (heading n°2925) for a cumulative charging power equal to or greater than 10kW.
Lead-acid batteries are the most widely used energy reserve for providing direct current (DC) electricity, primarily for uninterrupted power supply (UPS) equipment and emergency power system (inverters). There are two basic cell types: Vented and Recombinant Valve Regulated Lead-acid (VRLA) Batteries.
The ventilation system must prevent the accumulation of hydrogen pockets greater than 1% concentration. Flooded lead-acid batteries must be provided with a dedicated ventilation system that exhausts outdoors and prevents circulation of air in other parts of the building.