PER NFPA – SINGLE STATION SMOKE DETECTORS SHOULD BE TESTED MONTHLY AND BATTERIES REPLACED ANNUALLY
Single Station Smoke Detector
A single station smoke detector is a stand alone smoke detector that gives off an audible (and some times visual) signal that alerts the inhabitants of an area to the presence of smoke. It is manufactured in both Ion and Photo Electric models. However, Ion is the only type that I have found readily available.
The single station smoke detector is commonly used in single family residences, individual hotel rooms and apartments. It can be purchased at almost any hardware store with prices ranging from $5 to $25 dollars.
The single station can be purchased for use with 9 Volt DC (VDC), 110 Volt AC (VAC) or and 110 Volt AC with 9 Volt DC battery backup power. The most familiar is the 9 Volt DC detector which is found in older residences. It can be installed with common household tools.
A problem with the 9VDC unit is that once the battery goes dead they rendered useless and the premises unprotected. Far to often the batteries are never replaced. All smoke detectors should be checked monthly and batteries replaced annually.
The 110VAC unit is a more dependable model. It of course solved the problems associated with the battery type of detector. However, the 110VAC type would not work during power outages. Hence, the combination 110VAC and 9VDC detectors. I highly recommend the combination detector.
Warning: 110 Volt AC is very dangerous and can be deadly. Electrical devices and wiring should be installed by a licensed electrician only.