What is the Canadian Shield?
A CO detector is different than a smoke alarm. If one alarm has a week battery back up then they all will be effected. So find the bad one and replace it. If you do not have battery back up. Change them to that type.
Put this in the Search for questions box up above, then click the search button. There is all kinds of information there safe bedding for children
Call your local fire department non-emergency number and ask them. I would think that minimum, you must have smoke detectors in the hall and in each apartment.
