Code Question – I am designing a fire alarm system. Do I use the IBC or NFPA 72 for initiating device requirements?
The IBC (International Building Code), determines the fire alarm requirements for a building. Based on the building classification (Use Group), Section 907 tells us what type of fire alarm is required (manual fire alarm (pull stations) or automatic fire alarm (smoke detectors). The specific fire alarm requirements for a building are located in Section 907.2, organized by Use Group.
907.2 of the IBC states that fire alarm systems shall be installed per the requirements of the IBC and NFPA 72, with specifics for each building in sections 907.2.1 through 907.2.23, and notification requirements in 907.5, unless modified by another section of the code.
Section 907.4 details specific requirements for initiating devices on a fire alarm system required by the IBC. 907.4 parallels some of the requirements of NFPA 72 for initiating devices. Both codes require a smoke detector at the fire alarm panel, notification appliance circuit power extender, and supervising station equipment in locations that are not continuously occupied, and permit the use of a heat detector if the environment is not suitable for a smoke detector (IBC-907.4.1, 72-10.4.4).
Both require pull stations within 5 feet of the door, no more than 200 feet of travel to a pull station, a mounting height of 42” – 48”, and that they be red (IBC-907.4.2, 72-17.14). Both the IBC and NFPA 72 require at least one pull station on systems utilizing automatic detection or waterflow detection (IBC-907.2, 70-126.96.36.199.2). However, some IBC requirements go beyond the requirements of NFPA 72.
For example, the IBC requires that unmonitored fire alarm systems require signage at all pull stations stating WHEN ALARM SOUNDS CALL FIRE DEPARTMENT. The IBC also requires that pull station covers with sounders have AHJ approval. NFPA 72 does not address either of these requirements.
Where the IBC requires automatic detection, smoke detection is required. However, Section 907.4.3 states that if the environment is not suitable for smoke detectors heat detectors may be used. This section also permits the use of a sprinkler system that initiates the fire alarm system as an alternative to smoke detectors under the same condition.
Use Groups in Section 907.2 of the IBC that require smoke detectors may state specific coverage requirements, requiring smoke detectors in specific areas, or may simply require automatic smoke detection. The IBC may also require smoke alarms in specific locations but does permit the use smoke detectors as along as they function in a similar fashion to smoke alarms (only provide alarm notification in the unit).
NFPA 72 further defines detector coverage as total (all accessible spaces in the building, including above suspending ceilings), partial or selective (coverage as required by another code), and nonrequired (optional coverage provided for specific fire safety objectives, not required by other codes).
The most common type of coverage is partial or selective, with the coverage requirements being defined by the IBC. The IBC will require automatic detection in specific areas of the building.