There are a variety of smoke detectors for different applications from the typical round ceiling mounted smoke detector used in the typical home to the beam type that covers the entire ceiling of an office or factory.

The typical smoke detector has a 30 foot diameter detection area. According to NFPA code, this range may be modified up or down depending upon the surrounding environment and the height and slope of the ceiling. Each application has to be evaluated and the smoke detector applied as part of a "detection system". Code also specifies where smoke detectors must be located and all those locations must be covered if even one smoke detector is put on the alarm system. Gone are the days of the alarm salesman telling you that if you'll sign up today, I'll throw in a free smoke detector. One smoke detector will never meet code requirements.

The code requirements are the minimums that must be met but they in no way limit the number of smoke detectors that can be utilized. You should consider adding additional detectors if your budget will allow it
SEM Security Systems
a division of Southeast Mobility Inc
Smoke Detectors