What actions should be taken upon detecting a hydrogen leak in a confined space even when the concentration is below the Lower Explosive Limit (LEL)?

Upon detecting a hydrogen leak in a confined space, even when the concentration is below the Lower Explosive Limit (LEL), the following actions should be taken: First, immediately evacuate all personnel from the confined space to a safe area. Next, activate the ventilation system to increase air circulation and dilute the hydrogen concentration. Then, identify and isolate the source of the leak if it is safe to do so. This may involve closing valves, shutting down equipment, or other measures to stop or reduce the leak rate. Continuously monitor the hydrogen concentration using a calibrated gas detector to ensure that the concentration remains below the LEL and is decreasing. If the leak cannot be stopped or the concentration continues to rise despite ventilation, activate the emergency shutdown system (ESD) to isolate the hydrogen source and shut down the affected equipment. Finally, investigate the cause of the leak and implement corrective actions to prevent future leaks before re-entering the confined space. All actions should follow established safety procedures and be performed by trained personnel. Even if the concentration is below the LEL, a leak indicates a potential hazard that needs to be addressed promptly to prevent the situation from escalating.