A life safety alarm, for example a smoke alarm, that is battery powered, has an extended life, and is less prone to user mistakes. The batteries are sealed inside the alarm portion so that the batteries cannot be accessed by the user. As a result, the batteries are not replaceable. Rather, the alarm portion is replaced at the end of the alarm life, for example after expiration of a predetermined time period, such as ten years. The alarm is designed to be automatically activated upon initial attachment of the alarm portion to the bracket. The alarm can be manually deactivated, but once deactivated, the alarm cannot be reactivated and the alarm portion cannot be reattached to the bracket.