VRLA Battery Safety

VRLA Battery Maintenance and SafetyUTC Region 3 MeetingOctober 4, 20121Battery LifespanThe IEEE defines end of useful life for a UPS battery as being the point when it can no longer supply 80 percent of its rated capacity in ampere-hours. When the battery reaches 80 percent of its rated capacity, the aging process accelerates and the battery should be replaced.Expected life can vary greatly due to environmental conditions, number and depth of discharge cycles, and adequate maintenance.The risks of improperly maintained batteries are loss of capacity, fire, property damage, and personal injury.Factors that determine a batterys life span areAmbient TemperatureBattery Chemistry Positive Plate Design and ThicknessCyclingPreventive Maintenance2Why do batteries fail?Batteries can fail for a multitude of reasons, but common reasons are:High or uneven temperaturesInaccurate float charge voltageLoose inter-cell links or connectionsLoss of electrolyte due to drying out or damaged caseLack of maintenance, aging3How do batteries fail?Plate separation - Repeated cycling (charging and discharging), damage during handling and shipping and overchargingGrid corrosion - Normal aging, operating in an acidic environment and high temperaturesInternal short circuit - Heat (plates expand causing shorts), separator failure, handling and shipping, and grid corrosionExternal short circuit - Human error (shorting terminals) and leaksSulfation of plates - Sitting discharged for an extended period, not on charge or being underchargedExcessive gassing - Often due to high temperatures or overchargingDrying out - Excessive gassing, high temperatures or overcharging4What is thermal runaway?Thermal runaway occurs when the heat generated in a lead-acid cell exceeds its ability to dissipate that heat, which can lead to an explosion, especially in sealed cells. The heat generated in the cell may occur without any warning signs and may be caused by: Overcharging Excessive charging Internal physical damageInternal short circuit Hot environment.Battery temperature should be measured during PM checks.5Handling BatteriesA physical inspection of batteries should be made before handling:SwellingLeakingVisible DamageMetal watches or jewelry should not be worn while handling batteries. Wear safety goggles or other eye protection.Use of rubber gloves and apron is recommended.All tools should be adequately insulated to minimize the possibility of shorting.Keep sparks, flames, and smoking materials away from the battery area and explosive gases.In the event of contact with electrolyte, flush immediately and thoroughly with water.MSDS Sheets

Storing BatteriesDue to the self-discharge characteristics of lead-acid batteries, it is imperative that they be charged periodically during storage. To prolong shelf life without charging, store batteries at 10C (50F) or less.Store batteries in cool, dry, well-ventilated areas with impervious surfaces and adequate containment in the event of spills.Keep away from fire, sparks and heat.Avoid stacking too highAvoid excessive shock, impact, or dropping batteries

8Spills or LeaksMaterial safety data sheets (MSDS) should be available on site for reference if needed.You should always refer to the MSDS for specific precautionary measures.Stop the flow of materials, contain/absorb small spills with dry sand, earth, or vermiculite. Do not use combustible materials.If possible, carefully neutralize spilled electrolyte with soda ash, sodium bicarbonate or lime. Wear acid-resistant clothing, boots, gloves, and face shield. Do not allow discharge of un-neutralized acid to sewer.Spill containment systems may or may not be required for VRLA batteries. (Review local requirements that may apply)Transporting BatteriesVRLA batteries marked as non-spillable are safe and approved for all transportation methods by DOT for transportation by truck, rail, ocean and air transportation because they meet the requirements of 49 CFR 173.159 (d).Per 49 CFR 173.159(e) When transported by highway or rail, electric storage batteries containing electrolyte or corrosive battery fluid are not subject to any other requirements of this subchapter, if all of the following are met:(1) No other hazardous materials may be transported in the same vehicle;(2) The batteries must be loaded or braced so as to prevent damage and short circuits in transit;(3) Any other material loaded in the same vehicle must be blocked, braced, or otherwise secured to prevent contact with or damage to the batteries; and(4) The transport vehicle may not carry material shipped by any person other than the shipper of the batteries.

Disposal of BatteriesBatteries that are replaced can still contain a significant amount of hazardous waste, including the electrolyte and lead. You must comply with EPA guidelines for the disposal of all batteries.Many states require lead-acid batteries be recycledLarge generators have more stringent requirements for battery disposal guidelines and documentation.Only approved recyclers should be used to avoid problems with environmental concerns.

ConclusionsBenefits of preventive maintenance are:Increased lifespanGreater reliabilityReduced possibility of failureHandling of batteries require reasonable precautionTransportation of batteries is safe if properly prepared. Proper recycling or disposal of batteries is required.