Regulating Hydrogen in the Battery Room

The most dangerous thing in your battery room isn’t sulfuric acid. It isn’t even forklift batteries themselves, despite their crushing weight. The truly hazardous byproduct of charging batteries is invisible, tasteless, and odorless. It is lighter than air. And even a relatively small volume of it can cause a serious explosion.hydrogen gas detector alarm

We’re talking, of courses, about hydrogen. Battery charging areas must include vigorous ventilation systems to keep hydrogen from accumulating. That’s the message we hear from the full alphabet soup of industrial regulatory agencies, from OSHA to the NFPA.

Forklift Battery Gassing: Estimating the Risks

Governmental safety regulators have a good reason to require ventilation for charging areas. Hydrogen reaches its “lower explosion level,” or LEL, at a concentration of only four percent. It doesn’t take much hydrogen to start a fire, and when you add oxygen, which speeds up the reaction, you’ve got a potentially disastrous mix.

To make matters worse, hydrogen is lighter than almost any other element. It obeys the old maxim that “everything that rises must converge” and tends to accumulate at a room’s highest point. The hydrogen from a room full of charging batteries can form explosive pockets pretty quickly.

Ventilation is the solution. But what sort of ventilation?

Ventilation systems are rated in terms of how long they take to completely exchange the air in a given room. In order to figure out how much air your battery room vents should move, check out this Ventilation Calculator. Keep in mind that the industry standard for safe hydrogen levels is only one percent.

Eliminating the Hydrogen Threat From Industrial Battery Rooms

battery room hydrogen gas deteectorBefore you can vent hydrogen, you have to know that it’s there — easier said than done with this invisible hazard. Hydrogen Gas Detectors (HGD) from BHS warn staff when hydrogen starts to build up, well before it reaches potentially dangerous levels.

Hydrogen Exhaust / Ventilation FanRobust ventilation systems also include fans to force old air out and bring new air in. In order to save energy and air-conditioning costs, though, you wouldn’t want to run your fans continuously. That’s why the BHS Hydrogen Exhaust Fan (HEF) can communicate with an HGD to flush the room’s air only until hydrogen levels drop down to below safe limits.

For the highest level of protection from hydrogen, consider the comprehensive Battery Room Ventilation System (BRVS), which combines these innovations with extensive ductwork and gas-collecting Ventilation Stands to pipe explosive gasses straight out of your facility.

Ventilation for Battery Rooms is the Only Solution

Industrial batteries can’t help but emit hydrogen and oxygen during a charge. There’s no escaping physics.

Battery electrolyte is a mixture of sulfuric acid and water. Water, of course, is made of hydrogen and oxygen. Excess current breaks down water molecules, releasing these two gasses. Unfortunately, charging forklift batteries always leads to some amount of gassing toward the end of the charge.

That’s why OSHA regulations include prohibitions against anything that could introduce a spark into a column of hydrogen, including lit cigarettes, metallic tools around uncovered batteries, and electric arcs.

Along with the National Fire Protection Agency, OSHA insists that every battery charging area be provided with “adequate ventilation.” And they’re absolutely right.


Ducharme, Gerald N. “Ventilation for battery charging: a guide to designing a room ventilation system for commercial and industrial battery-charging operations.” Heating, Piping, Air Conditioning Feb. 1991: 43+. Business Insights: Essentials. Web. 26 Feb. 2016.

NFPA 70: National Electrical Code.NFPA. National Fire Protection Association, 2015. Web. 26 Feb. 2016.

Powered Industrial Trucks – 1910.178.OSHA. Occupational Safety & Health Administration, United States Department of Labor, n.d. Web. 24 Feb. 2016.