International Municipal Signal Association

Frequently Asked Questions

Question: How can I become a member?

Answer: Please print out this brochure and mail it in to the International. You may also complete the online version from the International' website.

Question: What is the history of IMSA?

Answer:  History

Question: I would like to know if a municipal fire alarm box installation falls under any ADA guidelines and if so, please reference which ones.

Answer: Provided by Lois Thibault (, Coordinator of Research. United States Access Board, 1331 F Street, NW, Suite 1000, Washington, DC 20004-1111

Call boxes, sidewalk telephones, and other pedestrian features are covered by title II of the ADA (State and Local Governments). There are three basic 'requirements':  

1: Newly-installed boxes must meet accessibility provisions for access to them, operating force, reach range, and clear ground space at controls; they cannot be protruding objects;

2: Altered boxes need to meet newly-installed requirements to the maximum extent feasible; and

3: Existing inaccessible boxes need to be prioritized for improvement under your transition plan. 

Here is a link to the current standard:; see 4.2-4.5 and 4.27 for specific provisions. (about 1/4 of the way through the document.)

 Also, here’s more information from the ADA website: 

Excerpt from the Accessible Rights-of-Way: A Design Guide: 

3.6.7 Miscellaneous Items

Other items commonly found on sidewalks—fire pull-stations, mailboxes (including curbside receptacles for overnight delivery services), information and sales kiosks, and fixed vending machines—should meet basic accessibility requirements for approach, reach range, and operating force and control. Sidewalk passage should not be narrowed by the placement or installation of such items, particularly at turns and ramps and in places that require additional maneuvering space to operate an element or feature. 

Other than having the manufacturers come into compliance with ADA requirements, fire boxes can be mounted parallel to sidewalks (but watch out for reach restrictions). Also, an empty box or some other item (flower pot) can be strapped to the base section within 0” – 27” for a person with a cane to detect the obstacle, again, not protruding further than the fire box itself.

Question: What is a Public Emergency Alarm Reporting System?
Answer: Public emergency alarm reporting systems shall consist of alarm boxes and alarm processing equipment that communicate on a wired or wireless network(s), one-way or two-way, meeting the requirements of this chapter. This shall include systems that use a communications infrastructure that is publicly owned, operated, and controlled. The requirements of this chapter shall apply to systems and equipment for the transmission and reception of alarm and other emergency signals, including those from auxiliary alarm systems, connected to the public emergency alarm reporting system. (NFPA 72 - 2010).

Question: Fire Alarm Wiring is Supposed to be Supervised, Right?
Answer: Supervision of a fire alarm notification appliance circuit (NAC) means that if an open or a short circuit exists on a circuit, the fire alarm control unit will indicate a trouble condition until the malfunction is corrected. Right? Well, that depends. 

If a NAC consists of DC operated appliances (horns, strobes and their combination's) then the above statement is true. Before or after the circuit has become activated, if a short circuit occurs on a DC NAC, the fire alarm control unit will isolate that circuit and shut it down preserving the integrity of the rest of the control unit. However, if the NAC is a voice alarm circuit, it’s a different story. UL 864, listing the manufacture of fire alarm control units, requires that a voice NAC which has a short circuit will be identified by the control unit and in turn will prevent the NAC from operating.

However, UL does not address a voice circuit that develops a short circuit after it has been activated. Therefore, a short circuit will prevent voice evacuation/relocation messages from being received by the people in or adjacent to the area of the fire. Furthermore, a short circuit in one area of the system’s NAC wiring could even compromise the entire voice evacuation of a building. 

Consider the following. A flaming fire starts in an electrical room or closet in which the NAC wiring has been installed for the appliances on a floor of a high-rise. It’s a fast evolving fire. The alarm sounds, and the fire floor, the floor above the fire floor and the floor below are evacuated automatically as programmed by the fire command center. The fire service arrives and after investigation they find that occupants on additional floors need to be relocated to other areas. However, the fire has advanced in the fire’s area of origin and has destroyed the NAC wiring, and as a result the conductors of the NAC on that floor have been shorted together. The circuit and the amplifier to which the circuit is connected has been put out of service due to the short. If the amplifier happens to be of the bulk variety where one amplifier provides the audio for the entire building, the audio evacuation portion of the system for the entire building has now been compromised if not rendered inoperative. Unlikely? Although this scenario may not occur within the first few minutes of the alarm, at some point during the evacuation/relocation process, it is quite possible. 

UL should include supervision after activation in the UL864 standard. However, on a performance based design, the interim fix to this problem is to install all NAC wiring, not just risers, in a 2-hour rated enclosure, or all NACs should be wired using circuit integrity (CI) cable. In addition, two NACs should be provided per floor or area of a building, each on a different audio power amplifier, with the two circuits wired to alternating speakers throughout the space so that only every other speaker would fail if a circuit failed. 

Whatever phase of this business you’re in…design, code enforcement, approval, installation, maintenance….we all know that the failure of even one NAC can be catastrophic. On your next project then, maybe you should think about protecting all NACs with CI cable until our national testing laboratories and our codes and standards people recognize this as a problem that needs their attention. 

This answer written by: Robert Hill - IMSA Fire Alarm Committee