To limit the probability of carbon monoxide gas entering living space undetected, which could lead to the acute poisoning or asphyxiation of persons.
[Clause (a)] To limit the probability that the carbon monoxide alarming devices will not be loud enough to wake sleeping occupants, which could lead to carbon monoxide gas entering living space undetected, which could lead to the acute poisoning or asphyxiation of persons.
[Clause (b)] To limit the probability that carbon monoxide gas will not be detected at or near its source, which could lead to carbon monoxide gas entering living space undetected or with less than the maximum possible warning time for occupants, which could lead to the acute poisoning or asphyxiation of persons.