Safety Precautions when handling Lead Acid Cells

Acid Mixing

An operator must wear protective goggles, clothing, shoes and gloves. Lead-lined wooden boxes or earthen ware vessels should be used for mixing water and concentrated acid. Glass or plastic containers must not be used due to the considerable heat generated during the process.

When mixing acid, pour the water in the mixing vessel first, then add the strong acid slowly and cautiously, stirring slowly.

NEVER ADD WATER TO ACID AS IT WILL “BOIL�? AND SPASH DANGEROUSLY

Acid Spillage

If acid is spilt on the floor, neutralise it as quickly as possible using an alkali eg soda or dilute ammonia (equal volumes of concentrated ammonia and water)

If acid is spilt on clothing, wash it as soon as possible with water and soap.

If acid comes into contact with the skin, wash it off with copious amounts of clean water.

In the case of acid in the eye, an eyewash bottle, using a saline solution, can be used. Alternatively, the patient should lie on his back while clean water is poured into the inner corner of the eye against the bridge of the nose, allowing to flow off at the outer corner. After first aid treatment, medical advice should be obtained immediately.

Explosion Risk

Metallic vessels should never be used for storing acid or topping up cells. Apart from the danger of acid contamination, a metallic vessel could short across the pillars of a cell, increasing the possibility of an explosion.

As synthetic materials such as nylon can hold static electrical charges under certain circumstances, clothing made from natural fibre is recommended, even though static electricity is unlikely to cause an explosion.

Smoking or naked lights are prohibited in a battery room. The only exception should be when work on a battery requires a flame. In such cases the battery should be disconnected from the charger and the fuses withdrawn. Before commencing such work, hydrogen gas should then be blown out from under the cell lids by removing the vent plugs and blowing into the cell through a rubber tube.

Under no circumstances should a flame be used near a battery on charge.

Avoid any action which may cause an electric arc when the battery is on charge. Ensure that all connections are kept tight to avoid any risk of such arcing.

Battery rooms must have sufficient ventilation to disperse the gases produced when a battery is on charge. If the room is enclosed, a ventilation system should be installed to ensure the air is changed regularly.

Cubicles in which the batteries are installed should have louvers in the upper and lower sections to provide a flow of air past the cells to dispense hydrogen being evolved. Such cubicles should provide sufficient clearance between the cubicle walls and the cell connections to prevent short circuit, which could result in a fire or an explosion.

Similarly, there should be adequate clearance between the rows of cells to prevent short circuits between them.

Electrolyte levels should not be permitted to fall below the tops of the plates, as flake of conductive material could bridge across two plates, causing an arc, which could ignite hydrogen gas.

The orifices of vent plugs should be kept clear of foreign matter, to permit gas to escape.

Handling of cells

All cells should be handled carefully as plastics containers can be damaged if they are dropped.

Cells should, where possible, be lifted by the shoulders of the container. If they are large or heavy, some means should be provided to enable two or more operators to lift the cell, such as lifting frames or jigs which fit under the shoulders of the cell, or webbing which can pass under the base of the container. Webbing may be used with cells which have flat sides and no shoulders.

Standby Power cells should never be lifted with lifting hooks passed through the bolt holes as there is always the danger that the pillars will slide up through the compound seal or rubber grommets, so that the weight of the container and electrolyte would be taken by the lid seal. Breakage could then occur.

Room Conditions

Illumination should be adequate to enable the cells to be easily inspected.

Gangways between rows of cells should be wide enough to prevent cells being dislodged by an operator working in a battery room. A platform ladder or movable trestle may be necessary to enable an operator to reach the upper row of cells for maintenance purposes. This should be made of wood.

Tools

Tools used for working on a battery must be insulated to prevent the danger of a short circuit from a tool dropped across battery terminals.