There are many ways to configure a fire alarm system to activate and notify others of an emergency
Buildings have different kinds of hazards, people with varying levels of mobility, and structures that affect occupants’ ability to evacuate in the event of a fire. That’s why the National Fire Protection Association’s NFPA: 101 Life Safety Code dictates different requirements for three key components of a fire alarm system, among others: what sets it off, how it alerts people in the building, and whether and how it must be monitored for the purpose of immediate response by emergency forces.
NFPA 101 calls these three components “initiation,” “occupant notification,” and “emergency forces notification.” In this article, we explore the various ways that a fire alarm system might accomplish these tasks according to code.
Check out later installments of this series to learn NFPA’s requirements for how each different occupancy type – the essential method by which buildings are classified – must uniquely fulfill these requirements.
What will initiate the fire alarm system?
Initiation, aka how the alarm goes off in the first place, can happen one of three ways: someone sets it off manually, a smoke detector or other automatic detection system triggers it, or an extinguishing system (e.g., overhead sprinklers) sets it off. NFPA 101, 9.6.2.1 lays those options out very clearly.
However, the particulars of those methods are less straightforward and depend largely on the occupancy type in which they are used. Read through all of Section 9.6.2 to learn what the essential (and rather detailed) initiation requirements are. As for understanding the basics of NFPA-compliant fire alarm initiation, the guidelines below should get you off to a good start.
Manual initiation
Let’s begin with manual initiation, –which is generally achieved by a manual fire alarm box, also known as a pull station. Section 9.6.2.3 details exactly where these manual fire alarm boxes should be located.
From the 2018 edition of NFPA 101
9.6.2.3 A manual fire alarm box shall be provided as follows, unless modified by another section of this Code:
(1) For new alarm system installations, the manual fire alarm box shall be located within 60 in. (1525 mm) of exit doorways.
(2) For existing alarm system installations, the manual fire alarm box either shall be provided in the natural exit access path near each required exit or within 60 in. (1525 mm) of exit doorways.
Be sure to also see Sections 9.6.2.4-5 for guidelines on how far apart manual fire alarm boxes may be placed from one another and from building exits. Also keep in mind that the specific code for your occupancy type most likely has additional requirements for where manual alarm boxes must go. In any case, all manual fire alarm boxes should be easily visible and accessible in accordance with section 9.6.2.7. And even if a building has an automatic detection or extinguishing system, this section still requires there to be at least one manual fire alarm box in the building.
Automatic detection
The second type of fire alarm initiation, automatic detection, can come in many forms. For example, some systems detect smoke, while others detect elevated heat or rate of rise, a measurement of how quickly the room temperature is increasing. The code for your specific occupancy will tell you which type of automatic detection system you need (if any). The most common type is the smoke detector, which must be automatic in cases where its coverage is considered “total” or “complete.”
From the 2018 edition of NFPA 101
Where a total (complete) coverage smoke detection system is required by another section of this Code, automatic detection of smoke in accordance with NFPA 72 shall be provided in all occupiable areas in environments that are suitable for proper smoke detector operation.
What, then, is total or complete smoke detector coverage?
NFPA 72: National Fire Alarm and Signaling Code defines it as coverage that includes “all rooms, halls, storage areas, basements, attics, lofts, spaces above suspended ceilings, and other subdivisions and accessible spaces.”(17.5.3.1) In short, if you have total coverage smoke detection, it should initiate the alarm system automatically.
Note: Most occupancies with sleeping units such as hotels, apartments, residential board and care, and others generally have smoke alarms rather than smoke detectors. And smoke alarms, much like in a one- or two-family dwelling, are required to be interconnected to each other within that dwelling unit – but aren’t always connected to the fire alarm system.
Extinguishing system operation
The third type of fire alarm initiation, extinguishing system operation, is often –equipped with automatic detection. In those cases, section 9.6.2.8 dictates that the extinguishing system is configured so that its water flow initiates the alarm.
From the 2018 edition of NFPA 101
9.6.2.8 Where a sprinkler system provides automatic detection and alarm system initiation, it shall be provided with an approved alarm initiation device that operates when the flow of water is equal to or greater than that from a single automatic sprinkler.
Section 9.7 gives additional guidance for a sprinkler system’s piping, usage in lieu of heat detection devices, and supervision for cases when those elements are required by other parts of the code.
Of course, not all fires can be put out or controlled by a typical sprinkler system, so section 9.8 makes provisions for alternative extinguishment systems to be used when a building’s contents would fuel one of these types of fires. When these alternative-type systems are used, the code requires actuation of the system to be indicated at a fire alarm panel (9.8.2.1 and 9.8.2.2).
Occupant notification: NFPA’s requirements may not be what you’d expect
Occupant notification is exactly what it sounds like: letting people in the building know that they need to get out immediately. There are a few different ways you can do this – and some will work better than others depending on who the building occupants are – but the NFPA provides one basic rule:
From the 2018 edition of NFPA 101
9.6.3.5 Unless otherwise provided in 9.6.3.5.1 through 9.6.3.5.8, notification signals for occupants to evacuate shall be by audible and visible signals in accordance with NFPA 72 and ICC/ANSI A117.1, Accessible and Usable Buildings and Facilities, or other means of notification acceptable to the authority having jurisdiction.
You can look into NFPA 72 and ICC/ANSI A117.1 for more details on installation, but the key takeaways here are “audible and visible signals.” And while that sounds simple, NFPA has a few things to say about just what these signals should entail.
From the 2018 edition of NFPA 101
9.6.3.7 Audible alarm notification appliances shall be of such character and so distributed as to be effectively heard above the average ambient sound level that exists under normal conditions of occupancy.
9.6.3.8 Audible alarm notification appliances shall produce signals that are distinctive from audible signals used for other purposes in a given building.
Basically, the nature of audible alarms –should be such that you will certainly hear them – whether you are sleeping, whether there is the noise from a crowd, or whatever ambient conditions exist. As for visible alarms, look at NFPA 72, 18.5.3 for details like the required pulse duration and flash rate of strobe lights, and read NFPA 101, 9.6.3.5.1-7 for all the cases in which you don’t actually need them.
There’s one other method of occupant notification, and that’s voice announcements. According to section 9.6.3.9, these should give instructions for how to evacuate the building or relocate to a safer part of it, and they can be either recorded or announced live. See sections 9.6.3.9.1-2 for more details on how a voice announcement should sound and be carried over an existing PA system.
It would be natural to assume that NFPA wants us to notify all occupants every time a fire alarm is triggered, but that’s not actually so. NFPA 101 actually allows some fire alarm notifications to occur on a “need-to-know” basis only.
From the 2018 edition of NFPA 101
9.6.3.6.2* Where total evacuation of occupants is impractical due to building configuration, only the occupants in the affected zones shall be initially notified, and provisions shall be made to selectively notify occupants in other zones to afford orderly evacuation of the entire building, provided that such arrangement is approved by the authority having jurisdiction.
9.6.3.6.3 Where occupants are incapable of evacuating themselves because of age, physical or mental disabilities, or physical restraint, all of the following shall apply:
(1) The private operating mode, as described in NFPA 72 shall be permitted to be used.
(2) Only the attendants and other personnel required to evacuate occupants from a zone, area, floor, or building shall be required to be notified.
(3) Notification of personnel as specified in 9.6.3.6.3(2) shall include means to readily identify the zone, area, floor, or building in need of evacuation.
The implication is that sometimes you don’t want alarms to cause panic for occupants who aren’t able to get themselves to safety, whether that’s because of the building’s limitations or their own. That’s what private operating mode in section 9.6.3.6.3(1) is all about. Check the code for your specific occupancy type to see if private operating mode is permitted in your building.
From the 2019 edition of NFPA 72
3.3.193.1 Private Operating Mode. Audible or visual signaling only to those persons directly concerned with the implementation and direction of emergency action initiation and procedure in the area protected by the fire alarm system.
If you backtrack through the code a bit, you’ll see that NFPA 101, 9.6.3.2.1-4 also present many cases where detectors don’t have to set off occupant notification, like smoke detectors for elevator hoist ways, closing dampers, and automatic door releases, to name a few. Note that in these exceptional cases, you may only forgo occupant notification if the detector’s power supply is monitored by the building’s fire alarm system and its activation signals a constantly-attended location.
Some occupancies will also allow alarms to run what’s called a “positive alarm sequence” in accordance with section 9.6.3.4.
NFPA 72 defines this as “an automatic sequence which results in an alarm signal, even when manually delayed for investigation, unless the system is reset.” (3.3.205) It allows 15 seconds for someone to acknowledge the signal at the fire alarm control unit before it automatically initiates notification signals and evacuation or relocation announcements (23.8.1.2.1.1(2)). If someone acknowledges the signal within that time, they then have 180 seconds to investigate the premises and either reset the system or confirm the alarm (23.8.1.2.1.1(3)).
Essentially, the alarm can be delayed from notifying occupants for a period of time while someone investigates the cause of its triggering – an especially handy feature in buildings where occupants may be tempted to set off an alarm when there isn’t really a fire.
If you need fire alarm monitoring, you have a few options
Fire alarm monitoring ensures that even if no one is in the building when a fire occurs, emergency forces will still be contacted. Typically, –monitored alarm systems will have a fire alarm control panel (FACP) installed which transmits any alarm signals to a supervising station. Not all occupancies require monitoring for their fire alarm systems, but those that do are held to section 9.4.6 of NFPA 101, which gives a few options for how to monitor alarms and notify emergency forces.
From the 2018 edition of NFPA 101
9.4.6.2 Where emergency forces notification is required by another section of this Code, the fire alarm system shall be arranged to transmit the alarm automatically via any of the following means acceptable to the authority having jurisdiction and shall be in accordance with NFPA 72:
(1) Auxiliary fire alarm system
(2) Central station fire alarm system
(3) Proprietary supervising station fire alarm system
(4) Remote supervising station fire alarm system
The most common of these methods, central station monitoring, connects the fire alarm system to a monitoring station via phone line, mobile line, Internet (IP), or another communication medium. Trained staff members then alert emergency services to the facility’s alarm signal. Auxiliary fire alarm monitoring works in the same way, except that instead of signaling a monitoring station, the alarm transmits directly to the municipal emergency force’s communication center.
Proprietary supervising stations are located within one of the several properties they monitor. This method is for owners of many different properties who want to take care of alarm monitoring themselves. Conversely, facilities with remote supervising station monitoring have alarms transmitted to any location that receives signals from properties under multiple different ownership. These types of monitoring stations aren’t subject to the recording and reporting requirements that govern how central station monitoring services must receive alarm signals. Section 26.3.9 of NFPA 72 details those requirements in full.
However the monitoring is to take place, visible and audible alarms should activate in that station when the system is triggered. If none of the monitoring options above are feasible, the facility may use a different, approved plan for notifying emergency forces. Refer to NFPA 72 for guidance on creating a compliant plan.
A fire alarm control panel.
Another determining factor in how to configure an alarm system is whether your state or city has adopted an edition of the International Building Code (IBC), and which year they have approved. IBC requires all sprinkler systems (except for those in commercial kitchens and one- and two-family dwellings) to be monitored by a supervising station.
From the 2018 edition of IBC
901.6 Supervisory service.
Where required, fire protection systems shall be monitored by an approved supervising station in accordance with NFPA 72.
901.6.1 Automatic sprinkler systems.
Automatic sprinkler systems shall be monitored by an approved supervising station.
Exceptions:
- A supervising station is not required for automatic sprinkler systems protecting one-and two-family dwellings.
- Limited area systems in accordance with Section 903.3.8.
Of course, whether or not your region has adopted the 2018 edition of IBC is far from the only thing that might require you to have your fire alarms monitored. Your occupancy type is the most important consideration in knowing exactly what’s required in terms of monitoring, and it determines a good deal of your initiation and occupant notification requirements as well.
What are the next steps in keeping your building’s fire alarm compliant?
Now that you’re up to speed on exactly what these components of a fire alarm system are, keep an eye out for the next two installments in this series. We’ll discuss exactly what each occupancy type needs for an NFPA-compliant fire alarm system and how building owners execute these model codes.
