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Opinions & Applications for the Fire Code (1997 edition) (revoked November 21, 2007)

9.8.4.1. INTERCONNECTED SMOKE ALARMS

9.8.4.1.

  "(1) Interconnected smoke alarms required in Sentences 9.8.2.2.(2) and 9.8.3.3.(2) and Clause 9.8.3.4.(1)(b) shall be installed on or near the ceiling in each
    (a) storey within a dwelling unit, including every basement, and
    (b) shared means of escape.
(2) Smoke alarms referred to in Sentence (1) shall be
    (a) electrically interconnected so that the activation of any smoke alarm will sound a similar signal in each of the interconnected devices,
    (b) installed in accordance with the manufacturers' instructions, and on floor levels containing bedrooms or sleeping areas, the required smoke alarms shall be installed between such bedrooms and the remainder of the dwelling unit, such as in a hallway or corridor serving such rooms or areas,
    (c) connected to an electrical circuit with no disconnect switch between the overcurrent device and the smoke alarms,
    (d) listed for use in an interconnected installation, and
    (e) audible in bedrooms when the intervening doors are closed."

Intent:

   The intent of this Article is to provide an economical system to provide early warning of a fire to compensate for deficiencies in fire separations or exits.

Other Resources:

   CAN/ULC-S531-M87, "Standard for Smoke Alarms, CAN/ULC-S553-M86, "Standard for the Installation of Smoke Alarms".

Application:

  
Q1:   Some two unit residential buildings have been provided with an electrical panelboard for each dwelling unit to control the circuits for that unit. Are interconnected smoke alarms on a 120 volt circuit an accepted practice under these circumstances?
A1:   The problem with this type of installation is that it is possible to turn off the power at the panel board in one dwelling unit and still have power to the smoke alarm circuit because it is connected to the panelboard in the other dwelling unit. This is an electrical safety issue which Ontario Hydro has addressed in their Bulletin 32-1-0 dated August 1996. Item 6 of this bulletin states that where separate dwelling units are supplied from separate panelboards in accordance with Rule 26-440, interconnection of the smoke alarms is only acceptable if it is accomplished by means of extra low voltage circuits (i.e. not exceeding 30 volts). The smoke alarms must be listed for low voltage use. At least one manufacturer continues to provide listed smoke alarms for low voltage circuits.