New carbon monoxide detector
law goes into effect


Legislative sponsors had touted the low cost of CO detectors to achieve passage of the new law, another argument that SPOA put forth that surely affected the final decision.

The deadline for installing detectors is March 31, 2006, or if you promise to go hardwired, January 1, 2007. If you have not yet installed detectors, NOW is the time to do it.

Difficult rule-making

The short time between the final regulations and the deadline to install these detectors – less than two months – reflects the difficult challenge that fire officials had faced in deciding what detectors to require, where to place them, and how to make sure that fire departments are not “rolling out the engines” for CO alarm calls, which indicate a “potential danger,” versus smoke alarm calls, which indicate an “immediate danger.” On this latter issue, which SPOA cautioned about, time will tell if the new law and regulations work effectively.

An awful confusion

Already there are hints of trouble with the new law.

“It’s an awful confusion,” said a SPOA member about the new carbon monoxide (CO) detector requirements. He owns nine units in Boston and 17 units in another major Massachusetts city, where he has had two visits from the fire captain and two phone calls with him to clarify what is required under the new law that goes into effect on March 31.

First the fire captain insisted that there had to be one CO detector in each unit and one in each common hallway. The captain called him back and said he was wrong. Unlike smoke detectors, which must be located in common hallways, no hallway CO detectors are required.

Then the same fire captain insisted that all CO detectors must “voice-announce” that the alarm is for carbon monoxide, not smoke. The captain later confirmed with the owner that he was wrong again. Only combination smoke AND carbon monoxide detectors must have the “voice-announce” feature telling which of the two alarms is sounding. (A smoke alarm signals an “immediate danger” while a CO alarm indicates a “potential danger.”)

These errors might be bad enough by themselves, but this fire captain had just returned from a meeting explaining the new requirements. “If this guy is any indication,” said the owner, “they are messed up, and they are the enforcers.”

Local fire chiefs are given the authority to enforce the new requirements. This owner predicts that “each locality and town will administer this law differently.”


Specific requirements

Here are as many rules as we could find from all sources. Bear in mind that enforcement may be strict, especially in an eviction battle, or lenient while the new law ramps up.


CO detectors must be installed by this coming March 31, 2006, unless an owner promises to do the special alternative option by January 1, 2007. The alternative option is usually applicable only to larger apartment buildings with rooms that contain centralized fossil-fuel burning equipment.

According to the new regulations, hardwired detectors also have a March 31, 2006, deadline, even though the new law itself and other information from the State Fire Marshal’s office say that hardwired detectors can be installed by January 1, 2007, if owners make a written promise by March 31 to the local fire chief to do so.

After March 31, 2006, all homes being sold or transferred to another owner must be inspected for CO detectors.


CO detectors are required in every dwelling unit in the state, regardless of the size of the unit, IF the unit contains any fossil-fuel burning equipment. That includes any equipment or appliance that burns oil, gas, wood, charcoal, kerosene, etc.

CO detectors are also required in every dwelling unit that contains enclosed parking, that is, an attached or enclosed garage, whether for one car or 100 cars.


A CO detector must be placed on every habitable level of every dwelling unit, including habitable spaces in basements and attics. A detector is not required in an uninhabited basement or attic, nor in crawlspaces. A detector is not required in common area hallways.

On levels that have sleeping areas, CO detectors must be located not more than 10 feet from any bedroom door. This rule may require more than one detector on the same level.

It appears allowable to place CO detectors in bedrooms, but it is preferable to place CO detectors outside of bedrooms, as they will act as an early warning before carbon monoxide builds up in the bedroom. The sound volume of CO detectors (85 decibels) is calculated to be loud enough to wake a normal sleeping person through a closed bedroom door.

CO detectors do not go in garages, but in adjacent living areas.

Owners with any tenant or resident with a hearing impairment must follow the rules of the Architectural Access Board. Rules must be obtained from the Board.

CO detectors can be placed at any height. Carbon monoxide spreads evenly up and down, but it will be in much higher concentrations and be more dangerous the closer one gets to the source of excess carbon monoxide.

Types of detector

All CO detectors must be UL listed or AIS/CAS listed.

The allowable types of CO detectors are:

1) battery-powered detectors with battery monitoring (a bleep signals a weak battery);

2) plug-in (AC powered) detectors with battery back-up;

3) hardwired (AC primary power) with battery back-up;

4) low-voltage or wireless detectors;

5) qualified combination smoke AND carbon monoxide detectors.

           Plug-in detectors without battery back-up are not allowed.

A “qualified” combination smoke AND carbon monoxide detector is one that has a simulated voice announcing clearly which alarm is going off as well as different tones for the different alarms.

Placement of combination smoke/CO detectors is problematic if the smoke detector functions by ionization (as opposed to photoelectric smoke detectors). The State Building Code prohibits ionization detectors within 20 feet of kitchens and bathrooms (too many false alarms). Unfortunately, combination units using photoelectric technology are not available yet.

Landlord duties

Landlords must inspect, test, maintain, repair or replace all CO detectors in rental units at least once a year or at the beginning of any rental period (such as lease renewal).

All batteries must be replaced annually. Owners should be aware that, unlike smoke detectors, the detecting function in battery-operated CO detectors uses up much more battery power. Annual battery replacement is therefore essential where batteries are the primary power source. (Back-up batteries probably last as long as smoke detector batteries, but the rules say all batteries must be replaced annually.)

Alternative option

The alternative compliance option can be used when the fossil-fuel burning equipment is centralized in specialized rooms (boiler room, centralized laundry room, centralized hot water room, etc.) or where there is a centralized garage. Owners considering this option should obtain detailed rules from their local fire department or the State Fire Marshal’s Office.