Why Does a Smoke Alarm Last Only 10 Years?

Power

• The life span of 9-volt batteries powering most smoke alarms is often variable so makers recommend replacing them annually. For longevity, 10-year life span lithium batteries sealed in some alarms eliminate replacement. Another power option is hard-wiring a detector into a home's domestic supply with a backup battery too in case of power failure. According to the National Fire Protection Association, 3 percent of smoke alarms fail per year. Despite adequate power, the likelihood of smoke detector breakdown increases with age.

Component Wear

• The push button used to test the battery power strength is often the only moving part in a smoke alarm that is liable to suffer wear through friction. Every individual component has a finite life expectancy and component failure will cause the unit to stop working. Repairing alarms or replacing faulty components is not customary and replacing a unit after a given time period ensures continued cover before failure can occur.

Contamination

• Steam and damp air from close proximity to a bathroom or laundry room may have a detrimental effect on a smoke alarm. Everyday airborne impurities, such as household dust, tiny insects and grease from cooking, will eventually infiltrate and contaminate the delicate parts inside an alarm. Regular cleaning can reduce the buildup of deposits but eventually they will cause the unit to function less effectively and finally fail altogether.

Safety Standard

• Even with the best care and maintenance, a smoke alarm will age and function less effectively. Due to the relatively low cost of these units, it is cheaper to replace them rather than to attempt repair. The independent safety advisory body, Underwriters Laboratories, has developed the safety standard that advocates a maximum 10-year life span for smoke alarms. They also advise consumers look for the UL mark when buying an alarm as a symbol of safety standards.