Originally Posted by Davydd
Those are code rules for sticks and bricks houses. One reason is to eliminate false alarms when close to a gas source thus eventual ignoring. Doors and windows can dilute the gas sensing. As far as I can tell CO detectors are the same as house detectors. I don't know of one specifically made for RVs. At least none of my three Class Bs hadn't.
The dual CO/LP detectors designed to be hardwired to the 12V system are specifically intended for RV/marine use. I honestly don't know if the sensing technology is different or not. I had heard vague suggestions on other forums it might be, but I have no definite knowledge. I assume the installation clearances at least are different.
I installed a simple battery-only residential-type CO detector in my travel trailer, and I had to fudge some of the specs a bit. I agree with your assessment of the reasons for avoiding certain locations. I'll add one more: dead zones with little air movement.