Article 3.2.4.4. describes how single and 2-stage fire alarm systems shall notify occupants.
The definition of alarm signal is ‘an audible signal transmitted throughout a zone or zones or throughout a building to advise occupants that a fire emergency exists’
Sentence 3.2.4.4.(1) for single stage systems specifically state that the alarm signal shall sound on all audible devices in system.
Sentence 3.2.4.4.(2) for 2-stage systems does not have the word ‘all’ when stating the alarm signal must sound if the alert is not acknowledged within 5 min. Based on that the definition of alarm signal refers to zones, it seems as though the designer chooses where that alarm signal sounds.
My questions are:
- Who designs the sequence of operations in a zone coded 2-stage alarm system and is there guidance provided in any of the fire alarm standards?
- What do AHJs typically require for documentation of the sequence of operations and what is it reviewed against?
- It seems as though an Alternative Solution for zoned notification is required for a single stage system as it is not prescriptively permitted…but for a 2-stage zoned notification has no guidance but meets prescriptively. Does this make sense?
One Response
The fire alarm DESIGNER is responsible for providing a number of important documents and drawings, not the least of which is the fire alarm systems “Sequence of Operation.” Section 4.7 of CAN/ULC-S524-14 (Including Amendment 1) – Standard for Installation of Fire Alarm Systems – is entitled “Plans and Specifications” and outlines what MUST be provided in every fire alarm system design. The very first sentence of this section (4.7.1) states:
“The plans and specifications for the fire alarm system shall include a complete and detailed description of the following:
A Sequence of operation;
B Installation instructions;
C Description of each type of field device;
D Details of input to programmed output functions for programmed systems; and
E Connection to a fire signal receiving centre, if required by the National Building Code of Canada.”
Sentence 4.7.2 states that “The plans of the building shall show the fire alarm zoning, device address and location of each field device of the fire alarm system, including fault isolators, ancillary devices, and annunciators or display and control centres.
Section 4.7 has a number of additional requirements as well. Unfortunately most of the plans and specifications I’ve reviewed fall far short of the requirements, and it frequently falls to the individual performing the Verification to ensure compliance with the Building Code, local bylaws, and the Standards.
As to your third question, CAN/ULC-S524 is fairly clear in Sentence 9.1.5.
“Audible signal devices and visible signal devices shall be installed in sufficient numbers to meet the audibility and visibility requirements of the National Building Code of Canada.”
On the audible side this is a minimum of 65 dBA with at least 10 dBA above ambient in common areas, and 75 dBA within sleeping rooms. I don’t quite agree that putting a 177 Candela strobe in a sleeping room is a good idea (as our southern neighbours have suggested). That first flash will definitely wake you up in a darkened room. The second will likely blind you temporarily. 🙂