Check the battery Material Data Safety Sheet or technical specification sheet to be certain of acid content. If this data is not readily available, use the Internet to find the battery manufacturer - most have very informative web sites. We have been able to obtain this type of information within hours of starting a search, with the manufacturer most willing to FAX the information to us. Large amounts of sulfuric acid must be reported under Federal law, more on this later.
While the flooded cell is forgiving in terms of charge and discharge they do present some well known hazards. In addition to the risk of sulfuric acid spills, the process of charging batteries can generate explosive amounts of hydrogen gas. The larger cells typically have vented caps to allow the gas to escape while blocking flames from reaching the internal portion of the cell. The Uniform Building Code and the National Electrical Code are national standards that address structural requirements for battery rooms. Both are excellent resources for general information. However, be sure to check your local code to ensure compliance.
An underrated and misunderstood hazard posed by large cell strings is the potential for a battery fire. Poor maintenance or installation may cause the inter-cell connections to overheat or cause the battery post(s) to melt down. Both of these conditions can lead to a short - resulting in a runaway condition which may soon result in a fire. Additionally, poor installation of seismic battery racks can result in extensive damage to the facility and sizeable chemical spills. Unfortunately, many view battery strings as a reliable, old technology which require little routine maintenance - nothing could be further from the truth.
We often hear -"Oh we don't need to worry about those batteries - they are maintenance free and leak-proof too!" The person in question here may be referring to a VRLA or Valve-Regulated Lead Acid battery. They could also be referring to a "gell-cell" or gelled electrolyte battery; possibly an Absorbed Glass Mat (AGM) battery or absorbed electrolyte battery. These common and erroneous, assumptions about maintenance requirements and leakage could lead to a disaster.
All of these battery types feature a sealed case; however, the physics of how each battery functions is significantly different. Valve-Regulated batteries are a type of sealed battery that, as the name implies, regulate the expulsion of excess hydrogen gas through a one-way valve or vent. VRLA batteries are often called captured electrolyte or capture mat batteries, they are sometimes called recombination type batteries. These names are indicative of the internal physics of the battery while the terms "vented" and "valve regulated" refer specifically to the mechanical device allowing the battery to expel excess gas.
VRLA batteries can contain significant amounts of sulfuric acid and they do vent explosive hydrogen gas. Worse still, they are very sensitive to temperature and charge rate. If overcharged, VRLA batteries can go into internal thermal runaway and explode. Additionally, some case swelling is considered "normal" though excessive case swelling may indicate trouble. All this information can be confusing - suspect battery plants should be surveyed by a professional battery technician.
Gell-cell batteries are a sealed case type of battery which recombine the hydrogen formed in the recharging process with free oxygen to form water which, in turn, keeps the cell "wet" or hydrated. The term "maintenance free" was coined by battery manufacturers in order to market recombination type batteries. Don't be fooled!
Batteries touted as maintenance free are, in fact, "reduced maintenance batteries." It is not necessary to routinely monitor the hydration of these batteries as with the traditional flooded-cells. However, these types of batteries do require routine maintenance. They should be inspected regularly for signs of stress. Two of the most reliable indicators of battery health are regular intercell resistance measurements and cell temperature measurements. All types of sealed batteries require careful charging and pose an explosion hazard.
The DR professional will have obtained copies of the material safety data sheet (MSDS) on any type of battery found in their area of responsibility. These sheets should be part of your overall HAZCOM or Hazardous Communications program mandated by Federal law.
What if you don't own the building housing your operations or are a tenet in a large complex? What does the law have to say about the use of batteries in occupied buildings?
Battery installations in occupied buildings are regulated by different standards, codes and laws. These rules may vary between States and local jurisdictions. Federal law, however, is in effect across the Nation and is often adapted directly for local code use - many times with more restrictive language than found in Federal regulations.
If you are responsible to do planning for a company which owns, operates, uses or has a lease in a building which contains large battery systems, read on to gain a greater understanding of possible exposure to personal or corporate liability under Federal and State law.
The primary law you must be aware of when planning is the Federal Emergency Planning and Community Right to Know Act, also known as EPCRA. EPCRA requires an owner or users of hazardous materials to notify the Local Emergency Planning Committee (LEPC), the State Emergency Planning Commission (SEPC), and the Local Fire Department or other agencies within that authority about hazardous chemicals.
Battery plants use significant amounts of sulfuric acid - found as the prime component of electrolyte fluid. Sulfuric acid is classified by the US Environmental Protection Agency (EPA) and Occupational Safety and Health Administration (OSHA) as an "Extremely Hazardous Substance". Because of this, large battery plants are usually registered with the local fire department. Registration is not voluntary, failure to register can result in large fines to a company. The planner looking for data on local hazards can check with the agencies listed above to discover if battery plants are in or near their area of operations.
This short article has covered the basics - where can you go for more information? Here are some Internet URLs which can give you a better understanding of this complex technology:
- www.epa.gov/region5 EPA information, Region 10 would be /region10 and so on
Source document for the HAZCOM program, mandatory for most businesses.
- www.epa.gov/swercepp/tech.html SARA title III "List of Lists" used to define trigger levels for reporting hazardous materials
NOTE: Inclusion of a URL does not constitute an endorsement by General Communication Inc.
Donald Koehler is the Business Continuity Manager for General Communication, Inc. He has over 25 years experience in radio, telephone and computer electronics maintenance.
Wendi K. Givigliano is the lead technical writer and maintenance program analyst for GCI. She has over ten years of experience in industrial facility operation and maintenance.
General Communication Inc. provides local, long distance, cable and entertainment, Internet and private line data communication services throughout Alaska. The company has several hundred earth stations in rural Alaska to support equal access and Internet service for even very small communities. GCI also owns and operates an undersea fiber optic system between Anchorage and Seattle Wa. Learn more at www.gci.com