Law Requires 2 Types of Smoke Detector Technology
The two most common methods of fire/smoke detection technology currently used is either ionization or photoelectric based.
Ionization sensors feature a constant current flowing between two electrodes. When smoke strikes the device, it impedes the current between the electrodes and causes the alarm to set off. Ionization sensors are usually quicker to go off than photoelectric detectors. The problem with ionization detectors is that they are not able to distinguish between smoke and steam. This makes them prone to false alarms when steam from a shower or other source interrupts the current. This is particularly true when the ionization detector is located near a kitchen or bathroom.
Photoelectric sensors send a beam of light between two sensors. This beam passes in front of the sensors in a direct line. When smoke cuts across the path of the light beam, some light is dispersed by the smoke particles causing it to activate the alarm. Photoelectric detectors are less sensitive to false alarms from steam or cooking exhaust fumes but may take longer than ionization detectors to operate. Another major concern is that ionization detectors do not offer the best protection in fires that smolder. Fires that smolder are some of the deadliest fires nationally. Photoelectric smoke alarms are more sensitive to smoldering, smoke producing fires. Most of the residential dwellings in the country have ionization detectors which are more sensitive to flames.
Tests of both types of alarms show that in smoke producing fires photoelectric detectors sound first and it takes nearly 17 minutes longer before an ionization alarm sounds.
New Fire Detector Regulations
Since there are strengths and weaknesses between photoelectric and ionization smoke detectors, the Board of Fire Prevention Regulation has passed a new regulation (527 CMR 32.00). According to the new regulation, owners of certain residential buildings will be required to install and maintain both the ionization and photoelectric smoke detectors. While the new regulation does not change the locations where smoke detectors are required, it does call for the installation of both technologies in certain locations.
Under the new regulation, an ionization detector can not be placed within 20 feet of a kitchen or a bathroom containing a shower or a tub. In these locations only a photoelectric detector is allowed. In order to comply with the law you can either install two separate detectors that have both technologies or by installing one that utilizes both.
What Properties Are Affected By The New Regulation?
In order to determine if a property is affected by this change you may consider checking with the local fire department. According to the new amendment the following types of properties are impacted by the new regulation:
- Residential buildings under 70 feet tall and containing less than six dwelling units.
- Residential buildings not substantially altered since January 1, 1975, and containing less than 6 residential units.
- All residential buildings sold or transferred after April 5, 2010, which are less then 70 feet tall, have less than six units, or have not been substantially altered since January 1, 1975.
For all properties in these categories, compliance is mandated by April 5, 2010. It should be noted that the law does not apply to these larger buildings or those which were substantially altered since January, 1975, as these properties already were required to upgrade their fire safety systems under other existing laws.
One other important note regarding smoke detectors: Many towns require hard wired smoke detectors and NOT battery operated. You should make certain you know what the requirement is for the town where the property is located in. As a general rule according to the State fire Marshall’s office, the law is as follows:
- Homes built after 1975 are required upon sale or transfer to comply with the State Building Code in effect at the time of construction.
- Homes built before 1975 are required upon sale or transfer to comply with the requirements of MGL c. 148, §26E(A); and
- Homes built between 1975 and 1998 are required to have hard wired interconnected smoke detectors outside the bedrooms and one detector on each floor at the top of the stairs. The smoke detector at the top of the stairs can be the same detector that is required outside the bedroom.
- Homes built after 1998, smoke detectors are required to be interconnected and have a battery backup. Smoke detectors are required in each bedroom, outside the bedroom and at the top of each flight of stairs. A single detector can satisfy multiple location requirements, if sited properly. There must also be one smoke detector on each level and one smoke detector for each 1,200 square feet of living space.
- The requirements for newer construction also apply to additions and/or renovations where a bedroom is either added or substantially altered. If an addition or renovation involves adding or substantially changing a bedroom, the entire house, including existing bedrooms must be brought up to the present standard according to the Massachusetts State Building Code (780 CMR), regardless of when the original home was built.Carbon Monoxide detectors are required in any residence that has fossil-fuel burning equipment including, but not limited to, a furnace, boiler, water heater, fireplace or any other apparatus, appliance or device; or has enclosed parking within its structure.
According to the carbon monoxide regulations, you need to have a detector on each finished level of the home. Further there must be a detector placed within ten feet of all the bedroom doors. The detectors do not need to be hard wired. A plug-in or battery operated detector meets the requirements and usually the most viable choice. Here are all the types are carbon monoxide detectors that are allowed:
- Battery powered with battery monitoring;
- Plug-in (AC powered) units with battery backup;
- Hardwired AC primary power with battery backup;
- Low-voltage or wireless alarms with secondary power; and
- Certain combination smoke detectors and CO alarms