Grill The Fire Expert

The Answer is Simple
I turned in drawings and specification sheets for a sprinkler monitoring system. My AHJ is telling me I have to install horns and strobes throughout the building, but not manual pull boxes. This is a light-manufacturing building. Where does it say any of this in the codes? Do the HVAC duct detectors need to be tied in my sprinkler monitoring panel to annunciate shut-down? We use the IBC, 2000 edition.

A: This question is asked often. The answer is really simple. Since the 1993 edition, NFPA 72 defines “fire alarm system” as a system or portion of a combination system that consists of components and circuits arranged to monitor and annunciate the status of fire alarm or supervisory signal-initiating devices and to initiate the appropriate response to those signals.

The words, “to initiate the appropriate response to those signals,” tells you that these systems could be for either evacuation, relocation, and/or notification of the fire department. However, your AHJ’s confusion is coming from this definition alone. Since the AHJ is hired to enforce the adopted building code(s), lets look there for some other clues.

  • The International Building Code. If the building isn’t required to have a fire alarm system per the fire alarm section of the code (IBC 907), then a fire alarm isn’t required. Section 907.2 of the IBC is called “Where required.” Here it states that a fire alarm system “shall be provided in accordance with 907.2.1 through Section 907.2.23.” Very specific and very simple.

To see where it is required, you must find the Use Group designation letter for your building within the next 23 paragraphs in Section 907.2. (Back up and make sure you have the correct Use Group.)

Your AHJ’s confusion is from the exception to the Group F requirements that reads “Exception: Manual fire alarm boxes are not required if the building is equipped throughout with an automatic sprinkler system and the notification appliances will activate upon sprinkler water flow.” Here it talks of omitting pull boxes and mentions the need for notification appliances, but this isn’t applicable if 907.2.4 doesn’t fit, and 907.2 tells you so.

As explained above, 907 only applies to buildings required to have a fire alarm system. Knowing this, take a look at the duct detector requirements in the International Building Code.

907.11 Duct smoke detectors. Duct smoke detectors shall be connected to the building’s fire alarm control panel when a fire alarm system is provided. Activation of a duct smoke detector shall initiate a visible and audible supervisory signal at a constantly attended location. Duct smoke detectors shall not be used as a substitute for required open-area detection.


  1. The supervisory signal at a constantly attended location is not required where duct smoke detectors activate the building’s alarm notification appliances.
  2. In occupancies not required to be equipped with a fire alarm system, actuation of a smoke detector shall activate a visible and audible signal in an approved location. Smoke detector trouble conditions shall activate a visible or audible signal in an approved location and shall be identified as air duct detector trouble.”

There it is, in Exception #2.

Greg Kessinger, SET, CFPS, president of an alarm installing company since 1981, teaches NICET training classes to fire alarm system designers and installers and continuing education seminars for Ohio’s fire alarm inspectors. You can reach Greg Kessinger at 888-910-2272; e-mail:; or visit his website at