Battery Safety:
General Battery Safety
A lead-acid battery by its very nature exposes personnel to several potentially dangerous elements: sulfuric acid, explosive gases, electricity, and heavy weight.
1. A solution of sulfuric acid and water is used as the electrolyte in lead-acid batteries, and has a concentration of sulfuric acid by weight of 37% to 43% in a fully charged condition. This
corresponds to a concentration by volume of 25% to 30%. Even in a diluted state, sulfuric acid
is a strong oxidizing agent and can burn skin and eyes and produce holes in clothing made of
materials such as cotton and rayon.
2. An explosive mixture of hydrogen and oxygen is produced in the battery during the charging process. These gases can cause the battery cells to explode if a spark or flames are present. Due to the lightness of hydrogen, it should readily diffuse into the atmosphere before it can collect into an explosive mixture. However, if not properly dispersed, it can explode if a means of ignition is present.
3. Electricity is produced by the battery, and while most persons cannot “feel” voltages below 35 to 40 volts, all batteries should be regarded as potentially dangerous. A lead-acid battery is capable of discharging at extremely high rates, and under a direct short of even a few cells, can cause much damage and serious injury.
4. The weight of industrial batteries can crush hands and feet if care is not taken during handling. The average motive power battery weighs in excess of 2,000 pounds. Adequate and proper handling equipment should always be provided.
Handling & Changing Safety
Wearing Jewelry
Personnel who work around batteries should not wear jewelry made of conductive material. Metal
items can short-circuit a battery and in the process become hot enough to cause a severe burn.
Removing Batteries
If a battery is to be removed from a truck, (1) bring the fork to ground level, (2) open the electrical
circuit of the truck (turn key or switch off), (3) set the brakes or chock the wheels, and (4) unplug the battery. The same procedure applies if the battery is to be charged in the truck. Never try to move a battery by pulling its cables. Batteries should be changed or charged only by personnel who are trained and authorized to perform these jobs.
Protected Chain Hoists
In cases where commercial battery handling equipment is not available, batteries may be handled
with protected chain hoists. Chain hoists should be equipped with a chain container or bucket to prevent a dangling chain from shorting the battery. If a container or bucket is not available, the battery may be covered with a nonconductive material such as plywood or plastic. An insulated battery lifting beam can be used with almost any type of overhead hoist.
Protective Eyeglasses and Headgear
The use of safety glasses and safety hats made of a nonconductive material is suggested when
batteries are being handled or serviced.
Lifting Batteries
Steel-trayed batteries have holes or eyes for lifting. Using the eyes in conjunction with a insulated battery lifting beam with safety latch and an overhead hoist is the recommended way to lift a battery. If a battery is lifted with two chains attached to a hoist at a single, central point forming a triangle, the procedure is unsafe and can damage the steel tray.
Battery as a Counterbalance
In most industrial trucks, a battery is used as a counterbalance for a carried load. Before installing a new or different battery, check with the manufacturer of the truck for the recommended range of battery weight. The battery service weight is usually stamped into the steel tray near one of the lifting holes. A
battery with the wrong weight can change the center of gravity of the truck and cause it to upset.
Battery Charging Safety
Charging Rooms
Plants that change batteries at the end of each shift should have one or more centralized areas designated for battery changing. These battery charging areas should be equipped with overhead hoists, conveyors, and cranes or their equivalents for handling batteries safely and conveniently.
Battery charging areas should be adequately ventilated, either through natural or forced ventilation. “Adequate ventilation” is difficult to define as it is dependent upon a variety of factors such as number and size of batteries being charged at one time, room size, ceiling height, air tightness of the building, etc.
No Smoking, No Open Flame
Because an explosive mixture of gas can exist in and around charging batteries, anything that
could ignite the gas, such as open flame, arc, spark, or smoking materials should be prohibited in battery charging areas. It is recommended that “No Smoking” signs be posted prominently in charging areas.
Insulated Battery Charging Racks
When batteries are charged in racks, the racks should be insulated to prevent the possibility of
sparking. The supports on which a battery rests should be made of nonconductive materials or be suitably insulated.
Charger Connections
Before connecting a battery to, or disconnecting it from a charger, the charger should be turned
off. Live leads can cause sparking and arcing as well as undesirable pitting of the contact surfaces of plugs or connectors.
Fire-Fighting Equipment
In addition to automatic sprinkler equipment that might be present, charging areas should be
equipped with a suitable hand-operated fire extinguisher. Consult local fire authorities or your insurance carrier for the class and size needed and for recommended mounting locations.
Ventilation
The ventilation system in a charging room should conform to local codes and ordinances. If the
average hydrogen concentration throughout the charging room does not exceed 1% by volume, the
ventilation is considered to be satisfactory. (Concentrations between 4% and 74% are explosive.) A variety of instruments such as combustible gas indicators and flammable vapor indicators are
commercially available for continuous and automatic analysis of hydrogen concentrations in the air.
Contact HAWKER if more information on these indicators is desired. When charging an enclosed or covered battery, whether it remains in the truck or is placed on the rack, always keep the battery tray cover and the truck compartment cover open throughout the entire charging period. Opening the covers helps to cool the battery and disperse the gases.
Battery Gassing
The gases given off by a lead-acid storage battery on charge are due to the electrolytic breakdown
(electrolysis) of water in the electrolyte to produce hydrogen and oxygen. Gaseous hydrogen is
produced at the negative plate, while oxygen is produced at the positive. Hydrogen is the gas
which is potentially problematic. It will burn explosively when ignited if the air contains between
4% and 74% hydrogen (less than 4% or more than 74% hydrogen will not explode). Hydrogen,
which is the lightest known gas, is 14 times lighter than air and rises and disperses very rapidly.
Normally, insignificant quantities of gases are released by a battery during the first part of the
charge, as most of the charging current is used in charging the battery. Only during the last stages
of the charge does the process become inefficient, so that an increasing portion of the current is
used up by the creation of heat and gases. If, instead of being used to charge the battery, an ampere-hour of charge is used completely to produce gas, it will create 0.01474 cubic feet, or 0.418 liters, of hydrogen per cell at standard temperature and pressure. Stated another way, 68 AH of charge, used completely to produce gas, will create approximately one cubic foot of hydrogen per cell.
To determine exactly how much hydrogen is released by a battery at any moment of the charge is
rather difficult, as each case will be different. However, the total amount released may be
approximated by the following method. It is based on the concept that a completely discharged
100 AH battery requires 100 AH of charge to bring it to full charge, plus overcharge needed to
make up for inefficiencies of charging such as heating and gassing.
Eyewash and Emergency Shower Facilities
The kinds of equipment available for eyewash and acid neutralization vary widely as to capability
and cost. Regardless of the equipment selected, it should be located in the immediate work area.
The three most popular types of equipment are described below.
• Chemical Burn Station. This is the lowest cost type of safety equipment. It consists of a plastic squeeze bottle containing a buffering solution for the relief of acid burns on skin, clothing, or in the eyes. The bottle usually holds about a quart of solution. It is held in a brightly colored, molded receptacle about 11⁄2 feet square that can be mounted on the walls of the battery charging areas or battery repair shops. Its use is practical in smaller battery charging areas and at battery repair shops where acid with a specific gravity of 1.400 or higher is not handled. Before installing chemical burn station equipment, check to see if it is acceptable to your company’s Safety and Medical Departments.
• Eyewash Fountain. A water fountain–type of device with two openings that facilitate washing both eyes at once. This type of safety equipment is useful when 1.400 specific gravity acid is regularly used for gravity adjustment, etc.
• Deluge Shower. This is a shower-type device with a handle or foot treadle for turning it on full force. When high specific gravity sulfuric acid (above 1.400) is handled regularly, it is recommended that
a deluge shower and an eyewash station be installed.
Vent Caps Stay In
Keep the vent caps in the cells at all times, except when removal is necessary to service or repair the cells. This precaution reduces the probability of electrolyte splash and prevents foreign matter from entering and damaging the cells.
Acid Handling Safety
Acid Splash in the Eyes
Acid splashing into the eyes is the most dangerous condition possible while handling higher specific gravity acid or electrolyte. If splashing occurs, the eyes should be immediately flooded gently with running water for at least 15 minutes. Medical attention should be obtained as quickly as possible. Special care should be taken to check for persons wearing contact lenses. If acid splashes into the eyes, the lenses should be removed and the eyes thoroughly rinsed. WARNING: Do not place a buffering or neutralizing agent in the eyes without the approval of your Safety Department.
Acid Splash on Skin
Acid or electrolyte spilled or splashed on the skin should be washed off with running water. If a
burn develops, report the incident to a supervisor and seek medical treatment.
Acid Splash on Clothing
When acid splashes on clothing, use a weak solution of bicarbonate of soda to neutralize the acid. When clothes are soaked with acid or acid is splashed over large areas of clothing, remove the
clothing, neutralize the acid with bicarbonate of soda, and/or rinse with running water. The sooner the clothing is rinsed, the less likely it is that the clothing will be damaged.
Protective Clothing
Normal work clothing can be worn in battery charging and battery repair areas for routine battery
work. Acid-resistant clothing is not as susceptible to acid damage as garments made of cotton, rayon, or similar materials. Appropriate personal protective equipment such as that listed below should be worn when servicing batteries:
• Acid-resistant gloves
• Acid-resistant arm gauntlets
• Acid-resistant apron
• Acid-resistant boots
• Acid-resistant cover goggle or cup goggle plus face shield
Pouring Acid
A carboy tilter or safety siphon should be used when acid is removed from a carboy container. A venting device in a carboy will provide uninterrupted flow and prevent splashing. Never move a carboy of acid without its protective box. Store acid carboys in a cool place and keep them out of the direct sunlight.
Storing Acid and Electrolyte
Battery electrolyte and sulfuric acid solutions should be stored only in covered containers made of
chemically inert material such as lead, glass, or acid-resistant plastics. Avoid using nylon containers as nylon has poor acid-resistant characteristics.
Protecting Floors in Battery and Charger Rooms
The floors in battery and charger rooms should be sloped toward a sump. Acid spillage should be
neutralized before discharging into a sewer. Even though the floor is protected with an acid resistant
coating, it should nonetheless be washed down with water after an acid spillage. Check all local and EPA ordinances to make certain you are in full compliance with all regulations governing the use, maintenance, and disposal of lead-acid batteries.
Neutralizing Acids and Electrolyte
Sulfuric acid can be neutralized with several different chemicals. All should be handled with great
care. We recommend using a commercially produced neutralizing agent.
Note: The information presented is of a general nature and should NOT BE CONSTRUED AS A LEGAL OPINION.
