Smoke detector and CO detector installed next to each other?
 

Is there any code that specifies a minimum required distance between a
ceiling-mounted smoke detector and a ceiling-mounted CO (carbon
monoxide) detector? My initial thought is that since there are
commercially available combo smoke/CO detectors, installing them next
to each other wouldn't be an issue. However, I wasn't sure if there
was any code or other requirement that applied to the installation of
two discrete units.

Smoke detector and CO detector installed next to each other?
 

no

Smoke detector and CO detector installed next to each other?