Smoke Detectors - How long do they last?

This is a question that frequently comes up and contrary to popular opinion they do not last forever! As with most everything regarding fire alarms the answers can be found in the National Fire Alarm Code, better known as NFPA 72. The prevailing question is what type of building are we dealing with? In a residence the low voltage smoke detectors need to be changed every ten years at a minimum. In a commercial building they need to have sensitivity testing every other year and should be cleaned every year. As long as the sensitivity readings are within manufacturers specifications the smoke detectors can be left in place. Once their sensitivity reading falls outside of the manufacturers specifications they should be replaced. The problem with this system is that there is no way to enforce this rule within a private residence and while all commercial fire alarms are supposed to have an annual test and inspection not all fire officials ask for a fire alarm test and inspection report when conducting their annual inspections.