Lift Truck Tips: Minimizing the risk of explosion in the battery room
The mere possibility of a hydrogen ignition can lead to big costs for an operation, but a solid monitoring plan can put workers, inspectors and insurance companies at ease.
Battery rooms are not known for being very pleasant places. Batteries, mounting racks, cabinets and floors must be routinely checked for leaking electrolyte, corrosion and sulfuric acid. Then, invisible health and safety risks remain, like the buildup of hydrogen gas generated during charging that could potentially become explosive. A proactive mix of proper battery room design, monitoring practices and ventilation can significantly reduce the likelihood of an incident or grievance, while keeping insurance costs down, according to Bill Rubenzer, vice president of Storage Battery Systems.
“Most electric lift truck users are aware there is a risk of explosion if there is a high enough hydrogen concentration and an ignition source,” Rubenzer says. “However, very few individuals really know how close they are to that explosive threshold in their facility.”
To avoid reaching a 4% concentration threshold, considered dangerous, many evaluate the risk of hydrogen buildup at the time of initial battery room installation, whether in a new facility or during a conversion from internal combustion lift trucks to electric. “After that, it either comes up after an ignition or when a worker or union expresses a concern,” Rubenzer says.
Ideally, a charging area would include wide open spaces with high ceilings that are far away from ignition sources like maintenance or welding operations. Associates should be instructed to always turn the charger off before disconnecting the battery, unless the charger is equipped with an arc-less disconnect feature. It is important to keep cable insulation and connectors in good condition by performing regular preventive maintenance.
A battery starts producing hydrogen gas during the “gassing phase,” which occurs during the last three hours of a standard recharge, says Rubenzer. This is when a hydrogen detection system can prove useful in alerting workers to a potential risk. A good charging area design will typically limit the hydrogen concentration in the room to under 1%, when a yellow warning light will appear. This can also be connected by relay to automatically activate a supplementary fan. At the 2% level, an audible alarm sounds with a red warning light. The system can be integrated into building alarm systems or other devices that can either shutdown the charging or alert personnel.
“To bring in an outside environmental company to review the risk of hydrogen buildup is expensive, and a fire inspector can only offer his interpretation of the codes,” Rubenzer says. “Having data on hand from hydrogen detectors will provide assurance that the risk is under control.”
An online hydrogen gas calculator is available to calculate hydrogen explosion risk based on battery room dimensions and the type of battery used.
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