PRECAUTIONS DURING BATTERY MAINTENANCE

BATTERY EXPLOSIONS CAUSE INJURY TO SHIP'S OFFICER

 

Narrative

A set of lead acid batteries, which supplied emergency power to a vessel's radio installation, was being serviced by a ship's officer. This work consisted of removing terminal connections, cleaning and greasing terminal posts and remaking the connections. The batteries were situated in a well ventilated box on the wheelhouse top. With the battery box cover removed the batteries were exposed to atmosphere.

The officer had completed the work on four of the eight terminals; there were four batteries in total. He was slackening the fifth terminal when two cells on this third battery exploded spraying him with acid and causing flying parts of the battery casing to strike him. A new battery was then obtained as a replacement. While this battery was being connected to the original three, one of those exploded, again throwing acid and parts of the casing over the officer. The vent caps had previously been removed from all three original batteries before installation of the new battery was attempted.

Fortunately the officer received only minor cuts and bruising.

Observations

The damaged batteries were discarded immediately after the incident so preventing any close examination or tests from being performed.

However, the battery manufacturers made several observations and recommendations:

Even batteries not under charge may discharge gases which have been trapped in their cells if the battery is moved or otherwise disturbed.

Charging or discharging current should be switched off before attempting to remove terminal connections.

Static discharges may be sufficient to cause the ignition of escaping gas.

Always keep cell vent plugs in place, even when charging the battery.

Full protective gear should be worn by persons working on lead acid batteries.

Comment

Some of the above points, together with further advice on working with lead acid batteries, is contained in Chapter 24 of The Code of Safe Working Practices for Merchant Seamen.

Handling of Batteries and Battery Rooms

1. Battery rooms are adequately ventilated to avoid accumulation. of explosive gases.

2. Light fittings and any electrical equipment in the battery room are of a type certified as being suitable for a hydrogen atmosphere.

3. Particular hazards when charging batteries are hydrogen explosion and short circuits. During charging, a battery gives off hydrogen and oxygen and the subsequent mixture can be easily ignited. Short circuits may cause arcing, which could lead to an explosion or bum seafarers.

4. Only authorized persons enter battery rooms and, when doing so, they ensure that they do not introduce any source of ignition. Smoking is prohibited in battery rooms.

5. Care is taken when using metal tools or implements to avoid making contact with the metal battery case or terminals.

6.      Battery rooms are kept clear of any equipment, including any other electrical equipment, likely to act as a source of ignition, and are not used as storerooms.

7. Lead‑acid batteries and alkaline batteries are not stored in the same room because of the possible interaction of the electrolytes.

8. Adequate lighting provides safe and effective means of inspecting and servicing the batteries and access to each cell

9.     Seafarers engaged in topping up the batteries wear personal protective clothing, gloves and goggles.

Warning: Open flames and naked lights should not be used to inspect battery cells.