I can give you general technical information, like the detectors will only detect the Carbon Monoxide gas in the location of the detector. If the detector is located in an apartment building's furnace room, it will detect the gas only in the furnace room. If the detector is located inside an apartment, it will only detect the gas in that apartment, not any other apartment.
Another issue with carbon monoxide detectors is they have an "Expiration Date". It's not the date that is etched in the law, it's the date that it just won't work anymore. Usually, when the carbon monoxide detector has reached the time it won't work anymore, it will somehow indicate trouble.
The detectors have a "Shelf Life"; the shelf life is based on the date of manufacture, not on the date of installation. If the detector is sealed in the factory container and it sits on a shelf, ready to install when another detector fails, the sealed detector's Expiration Date will still be the exactly same date as any other detector manufactured at the same time.
For a stand-alone carbon-monoxide alarm in a private residence or an apartment, the "Expiration-Date-Has-Been-Exceeded" indicator is usually a regular "Beep". The beeping sound is similar to the "Battery-Needs-Replacement" beep. Because most people don't keep the manufacturer's installation instructions for years, most people try replacing the batteries and wonder why the battery replacement doesn't fix the detector.
If the detector is using utility power, the detector will beep when the "Expiration Date" has been reached.
Similar "beeping" can come from smoke alarms
, furnace alarms, and other sources. Because the "Beeping" is hard to locate
, sometimes apartment of condominium residents even think that the sound is coming from the fire alarm sounder on the wall.
If the Carbon Monoxide detector is located in a commercial kitchen, a building's mechanical or furnace room, or other non-residential area, the detector commonly has a power supply. The detector also commonly sends any alarms to an outside monitoring company so help can be dispatched if carbon monoxide gas is detected.
Rules and Regulations Governing the Installation of Carbon Monoxide Detectors
I don't personally have copies of all the rules and regulations regarding the installation of Carbon Monoxide(CO) detection and warning equipment. The actual codes are scattered around in local, state, and federal government regulations. Some of the regulations are based on the International Building Code (IBC), various places in the National Fire Protection Association (NFPA) Code Books, and the International Fire Code (IFC), just to name a few of the places that regulate Carbon Monoxide detectors.
A lot of information, though, is available from the NFPA at:
Carbon Monoxide Alarms