Learning the NFPA Code for Replacing Smoke Alarms

In my January column, I mentioned the National Fire Alarm Code, NFPA 72, had no reference to the replacement of spot-type smoke detectors every 10 years. Although this statement is technically correct, clarification is needed. Code does indeed stipulate the replacement of spot-type smoke alarms every 10 years, but not smoke detectors. Confusing? Please read on.

This code reference came from Robert Schmidt of Sidney, Ohio’s Ohio Valley Integration Services Inc.: “Unless otherwise recommended by the manufacturer, single- and multiple-station smoke alarms installed in accordance with Chapters 18, 19, or 21 of NFPA 101, Life Safety Code, shall be replaced when they fail to respond to tests conducted in accordance with 8-3.4 but shall not remain in service longer than 10 years from the date of installation.” (Section 8-3.5, NFPA 72, 2002 Edition)

The 2002 handbook goes further in its instructions. Section 10.4.6 states, “Unless otherwise recommended by the manufacturer, single- and multiple-station smoke alarms installed in one- and two-family dwellings shall be replaced when they fail to respond to operability tests, but shall not remain in service longer than 10 years from the date of manufacture.”
The reason for this, according to the handbook, is that smoke alarms are not usually maintained to the extent that system-type smoke detectors are. “Therefore, replacement is required at intervals not exceeding 10 years,” it states.

Defining Smoke Alarms, Detectors

To better understand the issue at hand, it is important to know the definitions set forth in NFPA 72 – specifically those of smoke alarms, smoke detectors, single-station alarms and multiple-station alarms.

A smoke alarm is “a single or multiple station alarm responsive to smoke” and a smoke detector is “a device that detects visible or invisible particles of combustion.”

A single station alarm is “a detector comprising an assembly that incorporates a sensor, control components, and an alarm notification appliance in one unit operated from a power source either located in the unit or obtained at the point of installation.”

A multiple station alarm is “a single station alarm capable of being interconnected to one or more additional alarms so that the actuation of one causes all integral or separate audible alarms to operate; or one single station alarm device having connections to other detectors or to a manual fire alarm box.”

It’s important to know which type of sensor fits the definitions set forth in Section 10.4.6. For example, a single station alarm is the common, battery-operated detector found in most homes. This also includes the 120VAC detector that often comes with a 9V backup battery. The latter is usually the detector of choice for code enforcement officials.

The other type of smoke device fire technicians commonly work with is the smoke detector, which connects to a fire alarm system. It derives its operating power from an approved and listed power supply and is usually part of a compliant fire alarm control panel. Thus, a smoke detector is able to report alarms and potential trouble locally or to a central monitoring station.

The reason smoke alarms must be replaced every 10 years primarily relates to the durability of the detector itself.
According to NFPA, aging smoke alarms don’t operate as efficiently and often are the source of nuisance alarms. Older smoke alarms are estimated to have a 30-percent probability of failure within the first 10 years. Newer smoke alarms do better, but should be replaced after 10 years.

Technicians, especially security dealers who work in single- and multiple-family dwellings, often see smoke alarms as exclusively related to electricians – not an alarm company – because they usually install them in new homes.
When carefully looking at code issues surrounding these devices, it should be clear that there is an after-market opportunity for sales-minded technicians. Why not offer to replace these detectors in the homes you work in? For security dealers who work in homes, this represents a new sales opportunity. For those who have system-type smoke detectors in these environments, it still offers an opportunity to earn extra dollars.

“The new code requirements represent a great opportunity for all contractors, both security and electrical, to replace millions of outdated smoke detectors throughout the country,” says Schmidt.

Homeowners will not voluntarily ask fire technicians and security dealers to replace their old smoke alarms. Many need convincing that it’s a necessity. To do that, Schmidt says the industry needs to educate the end user and others in code enforcement.

“It is up to us to educate our customers and the local AHJs [authorities having jurisdiction] and to make them aware of the new code,” he says. “What a great opportunity to have the code mandate something that we all sell. Hopefully, this will create a huge demand for all the alarm dealer’s services.”

One objection fire technicians and security dealers are sure to hear from the homeowner is “why bother?” Perhaps the right answer in this case is “why not double your protection by assuring that the regular smoke alarms are working properly too?”

In any case, show them the code references and reason for concern, and allow them to make up their own minds.

Place Sensors in Sight of Smoke

A fundamental aspect of home spot-type smoke alarm/detector installation is knowing where to and where not to install them. All too often, these most critical fire sensors are installed too close to sidewalls and corners in hallways and rooms.
According to section 2-, NFPA 72, 1999 Edition, “spot-type smoke detectors shall be located on the ceiling not less than 4 inches from a sidewall to the near edge or, if on a sidewall, between 4 inches and 12 inches down from the ceiling to the top of the detector.”

If you stand back and look at the physical aspects of a room or hallway, it’s easy to see how smoke would flow from a fire. Smoke plume and ceiling jet must be considered when placing spot-type smoke sensors because they determine detection in a real fire situation.

When smoke detectors and alarms are installed without smoke flow in mind, detection may not occur in a timely manner, if at all. Smoldering, low-energy fires are a good example of where smoke detectors having to depend on the slow build-up and quantity of smoke to detect fire and sound the alarm.

Perhaps the easiest way to look at placement is in terms of how smoke commonly pushes clean air to the corners of a room or hallway. When a spot-type smoke alarm or smoke detector is installed too close to a room or hallway’s corners, detection will be delayed because smoke cannot reach the detector quickly enough.

Where a ceiling contains beams that could compartmentalize the overall surface, smoke detectors/alarms must be installed in such a manner where smoke will likely reach them. Where the beams are 12 inches or less in height and where they are less than 8 feet on center, smoke detectors/alarms can be mounted on the bottom of the beam surfaces as needed. And where beams extend downward 12 inches or more, each cavity between beams could be construed as a separate smoke cavity requiring its own spot-type smoke detector.

In future columns, we will further explore the mechanics behind spot-type smoke detectors, heat detectors, as well as line-type, photoelectric beam smoke detectors.

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