Residential Smoke Detection

By Thomas P. Hammerberg | Oct 15, 2012
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Now that the 2013 NFPA 72, National Fire Alarm and Signaling Code, is ready to hit the market, let’s look at the changes and review the installation requirements.

As we know, there has been a great deal of discussion regarding nuisance alarms in the last few years. Much of the discussion applies to commercial, residential and nuisance alarms in general.

For the residential market, some jurisdictions no longer allow ionization smoke alarms, due to concerns about nuisance alarms and that they will not respond to certain types of fires. NFPA 72 contains language in Chapter 29 that forbids installing smoke alarms within 10 feet of cooking appliances unless they are specifically listed for that location. Between 10 and 20 feet from the cooking appliance, either a photoelectric smoke alarm or a smoke alarm equipped with an alarm-silencing means is permitted.

There are a couple of exceptions to this requirement. Smoke alarms or detectors can be installed at a radial distance greater than 6 feet provided the kitchen or cooking area and adjacent spaces have no clear interior partitions or headers and the 10-foot area of exclusion would prohibit the placement of a smoke alarm or detector required by other sections of NFPA 72.

With all the debate about photoelectric versus ionization technology, both of which have been around since the 1970s with little or no development, a proposal was submitted—and eventually accepted—to require that, effective Jan. 1, 2016, all smoke alarms and smoke detectors used in a household occupancy be listed for resistance to common nuisance sources, including cooking. This requirement should allow manufacturers to start using some of the multi-criteria technology used today in commercial addressable-type smoke detectors. It is time to upgrade the technology of our household smoke alarms to make them even more effective in saving lives. If smoke alarms do not alarm from nuisance sources, it will be less likely that occupants will disable them.

Most nuisance alarms in homes can be avoided using today’s smoke alarm technologies if they are installed properly in accordance with the requirements in Chapter 29. Let’s review.

First, smoke alarms and detectors cannot be installed within 36 inches horizontally from a door to a bathroom containing a shower or tub. Steam can cause nuisance alarms. Smoke alarms and detectors also cannot be installed within 36 inches horizontally from the supply air registers of a forced air heating or cooling system and must be installed outside of the direct airflow from those registers. They also cannot be installed within 36 inches horizontally from the tips of ceiling fan blades. These requirements not only reduce dust buildup in the detectors but ensure the detectors’ ability to detect smoke isn’t hindered as a result of airflow. Additionally, the alarms and detectors cannot be installed in unfinished attics or garages where the temperature can fall below 40°F (4°C) or exceed 100°F (38°C) or where ambient conditions (including humidity and temperature) are outside the listed limits of the devices. In all cases, if smoke alarms or detectors are listed for the location, obviously they may be installed there.

Other installation limitations include not installing the alarms or detectors on a mounting surface that could be considerably warmer or cooler than the room, such as on an exterior wall or ceiling with poor insulation. Alarms and detectors should be installed on inside walls. For tray-shaped ceilings, smoke alarms and detectors must be installed on the highest portion of the ceiling or on the sloped portion of the ceiling within 12 inches of the highest point. If the home has more than one level, the alarms or detectors must be located so that smoke rising in a stairwell will not be prevented from reaching the smoke alarm or detector by an intervening door or obstruction. If the home has a beamed or joisted ceiling, detector spacing must be reduced to comply with Section

Also keep in mind that each smoke and heat alarm must be powered by a commercial light and power source and have a battery backup. They cannot be connected to switched power, and the operation of a ground-fault circuit interrupter receptacle can’t cause the loss of the primary power.

Be aware of the new carbon monoxide requirements in the codes today as well, and consider using combination smoke alarm/-carbon monoxide alarms where fossil fuel burning appliances are installed in the home.

HAMMERBERG is the president/executive director of the Automatic Fire Alarm Association Inc. headquartered in Jasper, Ga. He serves on a number of NFPA committees, including the NFPA 72 Technical Correlating Committee and the Protected Premises Technical Committee. He can be reached at [email protected].

About The Author

HAMMERBERG, SET, CFPS, is an independent fire alarm presenter and consultant in The Villages, Fla. He can be reached at [email protected]

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