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National Fire Alarm Code Defined By NFPA 72
National Fire Alarm Code Defined By NFPA 72

Smoke And Fire Alarms

NFPA 72 is the National Fire Alarm Code. The importance of installing smoke and fire alarms in homes is supported by results from exhaustive investigations of home fires indicating that measurable quantities of smoke come before detectable quantities of heat.

In other words, smoke generally comes before fire. Because this is true, smoke alarms are considered the primary means of protection against fire in homes.

Following are some interesting facts about home fires.

Fires in homes were the third leading cause of deaths in homes – more deaths from asphyxiation than from burns. Half of fires in homes occurred between 10 pm and 8 am. That’s sleep time.

Chapter 29 of the National Fire Alarm Code specifically covers Single- and Multiple-Station Alarms and Household Fire Alarm Systems. It contains the minimum requirements for the proper selection, installation, operation, and maintenance of fire warning equipment that will provide reasonable fire safety.

Chapter 29 also covers small residential board and care occupancies, which are defined as A building or portion thereof that is used for lodging and boarding of four or more residents, not related by blood or marriage to the owners or operators, for the purpose of providing personal care services.

In NFPA 72, Section 29.1.2, we find that the primary purpose of fire warning equipment is to provide a reliable means to notify the occupants of the presence of a threatening fire and the need to escape to a place of safety before such escape might be impeded by untenable conditions in the normal path egress. NFPA 72 is not intended to provide protection to property, 29.1.5.

This chapter deals with the types of smoke and heat alarms typically installed in one- and two-family dwellings.

These smoke and heat alarms are not classified as fire alarm systems. This chapter does not involve the more complex household fire alarm systems, but rather the devices and a fire alarm control unit(s) that receive, monitor, and process signals from detection devices.

These types of fire alarm systems communicate via telephone or wireless with a central station that in turn calls the fire department. Fire alarm systems are required to meet stricter rules regarding the sound level and time of audible signals. There are also tougher rules regarding sleeping area requirements.

Fire alarm systems require rechargeable batteries from the AC power source supplying the control unit(s). Typical home-type smoke and heat alarms are permitted to have replaceable batteries.

Chapter 29 of the National Fire Alarm Code tells us where to install smoke and heat detectors and alarms in homes.

Heat detector
Heat detector (photo by bilic-eric.hr)

Article 760 in the National Electrical Code (NEC) tells us how to install the wiring for fire alarm systems. Section 29.3.2 of the National Fire Alarm Code states that fire warning equipment shall be installed according to the listing and manufacturer’s instructions.

Carbon Monoxide Detectors

There is nothing in the NEC that deals with carbon monoxide. To learn about carbon monoxide detectors and alarms in homes, we refer to NFPA 720, the Standard for the Installation of Carbon Monoxide (CO) Detection and Warning Equipment. Because carbon monoxide is said to be the number one killer, many communities have passed legislation adopting all or parts of NFPA 720.

NFPA 720 requires carbon monoxide detectors and alarms for all dwellings. Homeowners and landlords had better pay close attention to this! How often have you heard on the news or read in the newspaper that the carbon monoxide detectors did not work! The batteries were either dead or had been removed.

Equally important is that there is nothing in the National Fire Alarm Code that will prevent injury or death if proper escape routes have not been planned, 29.4.2.

Fire warning devices commonly used in a residence are heat detectors, Figure 26-1, and combination smoke alarms/detectors, Figure 2.

The more elaborate systems connect to a central monitoring customer service center through a telephone line. These systems offer:

  1. Instant contact with police or fire departments,
  2. A panic button for emergency medical problems,
  3. Low-temperature detection,
  4. Flood (high-water) detection,
  5. Perimeter protection,
  6. Interior motion detection,
  7. and other features.
Combination smoke alarm/detector
Figure 2 - Combination smoke alarm/detector (photo by gira.de)

All detections are transmitted first to the company’s customer service center, where personnel on duty monitor the system 24 hours a day, 7 days a week. They will verify that the signal is valid. After verification, they will contact the police department, the fire department, and individuals whose names appear on a previously agreed-on list that the homeowner prepared and submitted to the company’s customer service center.

NFPA Standards are not law until adopted by a city, state, or other governmental body. Some NFPA Standards are adopted totally, while only portions of others are adopted. Installers must be aware of all requirements in the locality in which they are doing work.

Most communities require a special permit for the installation of fire warning equipment and security systems in homes, and require registration of the system with the police and/or fire departments.

In most instances, fire protection requirements are found in the building codes of a community and are not necessarily spelled out in the electrical code.

Are Smoke and Heat Alarms Required?

Pay particular attention to the words found in NFPA 72 29.1.2, which states, Smoke and heat alarms shall be installed in all occupancies where required by governing laws, codes, or standards.

Similar wording is found in 29.5.1.1. This puts the responsibility on the local building department. It might seem confusing to have so many codes. Without question, you must become familiar with your local applicable laws, codes, or standards.

Most communities adopt building codes published by the International Code Council (ICC). These codes contain requirements for the installation of smoke alarms. Your local building department officials can explain what is required for new work and remodel work (alterations, repairs, and additions) where a permit is required.

Whereas new work requires interconnected, hard-wired, battery backup smoke alarms, it might be acceptable on remodel jobs to install battery-powered-only smoke alarms for existing areas where interior walls or ceiling finishes are not removed to expose structural framing members. To install, interconnect, and hard-wire smoke alarms in these existing areas could result in damage to walls and ceilings, requiring patching, repainting, or other repairs-an uncalled for and tremendous expense.

If there is access from an attic, crawl space, or basement, the inspector might require interconnected, hard-wired, battery backup smoke alarms if you can do the job without having to remove interior finishes.

Check this out with your local inspector!

Reference: Electrical Wiring – Residential 17th ed. – R. Mullin (Get it from Amazon)

About Author //

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Edvard Csanyi

Edvard - Electrical engineer, programmer and founder of EEP. Highly specialized for design of LV high power busbar trunking (<6300A) in power substations, buildings and industry fascilities. Designing of LV/MV switchgears.Professional in AutoCAD programming and web-design.Present on

2 Comments


  1. Ali basiri
    May 04, 2015

    Thank you for the information.

    How we can do earting system for building.

    Appreciate for your comment and advise.

    Regards,


  2. JOEBO COMIA
    Mar 04, 2015

    Thank you for the information.

    Currently I am handling the Fire Detection Alarm System inspections. I would like to ask/inquire, can smoke and heat detectors device installed without ceiling, like it was suspended from slab to device at 1ft.

    Appreciate for your comment and advise.

    Regards,

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