Ministry of Municipal Affairs
PROPOSED CHANGE TO THE 2012 BUILDING CODE
O. REG. 332/12 AS AMENDED
CHANGE NUMBER:
B-03-02-11
SOURCE:
Ontario-NBC
CODE REFERENCE:
Division B / 3.2.4.23.
DESCRIPTION OF THE PROPOSED AMENDMENT
This proposed change changes the intelligibility level of voice communication systems from a mandatory target to
a voluntary target level with guidance.
EXISTING 2012 BUILDING CODE PROVISION(S)
3.2.4.23. Voice Communication Systems
(1) A voice communication system required by Sentences (7) to (10), Subsection 3.2.6. or Clause 3.3.2.4.(14)(f) shall
consist of,
(a) a two-way means of communication with,
(i) the central alarm and control facility, and
(ii) the mechanical control centre from each floor area, and
(b) except as provided by Sentence (8), loudspeakers that are,
(i) operated from the central alarm and control facility, and
(ii) designed and located so that transmitted messages are audible and intelligible as required by Sentence (2) in
all parts of the building, except in elevator cars.
(See Appendix A.)
(2) The voice communication system referred to in Clause (1)(b) shall be capable of broadcasting pre-recorded,
synthesized or live messages with voice intelligibility meeting or exceeding the equivalent of a common intelligibility
scale score of 0.70. (See Appendix A.)
(3) The voice communication system referred to in Sentence (1) shall include a means to silence the alarm signal in a
single stage fire alarm system while voice messages are being transmitted, but only after the alarm signal has initially
sounded for not less than 30 s.
(4) The voice communication system referred to in Sentence (1) shall include a means to silence the alert signal and the
alarm signal in a two stage fire alarm system while voice messages are being transmitted, but only after the alert signal
has initially sounded for not less than,
(a) 10 s in hospitals that have supervisory personnel on duty for twenty-four hours each day, or
(b) 30 s for all other occupancies.
(5) The voice communication system referred to in Clause (1)(b) shall be designed so that the alarm signal can be
selectively transmitted to any zone or zones while maintaining an alert signal or selectively transmitting voice
messages to any other zone or zones in the building.
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(6) The voice communication system referred to in Clause (1)(a) shall be installed so that emergency communication
devices are located in each floor area near exit stair shafts.
(7) Except for Group B, Division 1 and Group F, Division 1 major occupancies, a voice communication system shall be
installed in a building where,
(a) a fire alarm system is required under Subsection 3.2.4.,
(b) a two stage fire alarm system is installed, and
(c) the occupant load of the building exceeds 1 000.
(8) A voice communication system required by Sentence (7) shall consist of loudspeakers that are,
(a) operated from the central alarm and control facility or, in the absence of a central alarm and control facility, from a
designated area, and
(b) designed and located so that transmitted messages are audible and intelligble in all parts of the building, except in
elevator cars.
(9) Unless staff trained to provide instructions over the voice communication system referred to in Sentence (8) are
present at all times, a pre-recorded message shall be provided.
(10) The voice communication system required by Sentence (7) shall meet the silencing and transmission requirements of
Sentences (3) to (5).
A-3.2.4.23.(1)(b) Voice Messages.
The concept of intelligibility expressed in Clause 3.2.4.23.(1)(b) is intended to mean that a person with average hearing and
cognitive abilities is able to understand the messages that are transmitted into the space occupied by the person. The
intelligibility of the message depends on the speech level, the background level, and the reverberation time of the space.
ISO 7731, “Ergonomics - Danger Signals for Public and Work Areas - Auditory Danger Signals”, addresses audibility. The
standard suggests that an A-weighted sound level at least 15 dB above the ambient is required for audibility, but allows for
more precise calculations using octave or ⅓ octave band frequencies to tailor the alarm signal for particular ambient noise
conditions. Design of the alarm system is limited to ensuring that all areas receive an adequately loud alarm signal. If a
public address system is to be used to convey instructions during an emergency, then the requirements of the system are less
straightforward.
A-3.2.4.23.(2) Voice Intelligibility.
Common intelligibility scale measuring requirements and guidance on the proper design of intelligible voice and alarm
systems can be found in Annex A7.4.1.4 of NFPA 72, “National Fire Alarm and Signaling Code”.
PROPOSED CODE CHANGE
3.2.4.23. Voice Communication Systems
(1) A voice communication system required by Sentences (6) to (9), Subsection 3.2.6. or Clause 3.3.2.4.(14)(f) shall
consist of,
(a) consist of a two-way means of communication with,
(i) the central alarm and control facility, and
(ii) the mechanical control centre from each floor area, and
(b) except as provided by Sentence (7), be capable of broadcasting prerecorded, synthesized, or live messages
loudspeakers that are,
(i) operated from the central alarm and control facility, and
(ii) designed and located so that transmitted messages are audible and intelligible as required by Sentence (2) in
all parts of the building, except in elevator cars.
(See Appendix A.)
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(2) The voice communication system referred to in Clause (1)(b) shall be capable of broadcasting pre-recorded,
synthesized or live messages with voice intelligibility meeting or exceeding the equivalent of a common intelligibility
scale score of 0.70. (See Appendix A.)
(32) The voice communication system referred to in Sentence (1) shall include a means to silence the alarm signal in a
single stage fire alarm system while voice messages are being transmitted, but only after the alarm signal has initially
sounded for not less than 30 s.
(43) The voice communication system referred to in Sentence (1) shall include a means to silence the alert signal and the
alarm signal in a two stage fire alarm system while voice messages are being transmitted, but only after the alert signal
has initially sounded for not less than,
(a) 10 s in hospitals that have supervisory personnel on duty for twenty-four hours each day, or
(b) 30 s for all other occupancies.
(54) The voice communication system referred to in Clause (1)(b) shall be designed so that the alarm signal in a 2-stage
fire alarm system can be selectively transmitted to any zone or zones while maintaining an alert signal or selectively
transmitting voice message instructions to any other zone or zones in the building.
(65) The voice communication system referred to in Clause (1)(a) shall be installed so that emergency communication
devices are located in each floor area near exit stair shafts.
(76) Except for Group B, Division 1 and Group F, Division 1 major occupancies, a voice communication system shall be
installed in a building where,
(a) a fire alarm system is required under Subsection 3.2.4.,
(b) a two stage fire alarm system is installed, and
(c) the occupant load of the building exceeds 1 000.
(87) A voice communication system required by Sentence (6) shall consist of loudspeakers that are,
(a) operated from the central alarm and control facility or, in the absence of a central alarm and control facility, from a
designated area, and
(b) designed and located so that transmitted messages are audible and intelligible in all parts of the building, except in
elevator cars.
(98) Where the facility is not equipped with staff trained to provide instructions over the loudspeakers, Unless staff
trained to provide instructions over the voice communication system referred to in Sentence (7) are present at all times, a
pre-recorded message shall be provided.
(109)
The voice communication system required by Sentence (6) shall meet the silencing and transmission
requirements of Sentences (6) to (4).
A-3.2.4.23.(1)(b) Voice Messages.
The concept of intelligibility expressed in Clause 3.2.4.23.(1)(b) is intended to mean that a person with average hearing and
cognitive abilities is able to understand the messages that are transmitted into the space occupied by the person. The
intelligibility of the message depends on the speech level, the background level, and the reverberation time of the space.
ISO 7731, “Ergonomics - Danger Signals for Public and Work Areas - Auditory Danger Signals”, addresses audibility. The
standard suggests that an A-weighted sound level at least 15 dB above the ambient is required for audibility, but allows for
more precise calculations using octave or ⅓ octave band frequencies to tailor the alarm signal for particular ambient noise
conditions. Design of the alarm system is limited to ensuring that all areas receive an adequately loud alarm signal. If a
public address system is to be used to convey instructions during an emergency, then the requirements of the system are less
straightforward.
Building and Development Branch
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Additional guidance on how to design and evaluate the intelligibility of a communication system can be found in the
following documents
• IEC 60268-16, Sound system equipment — Part 16: Objective rating of speech intelligibility by speech
transmission index, International Electrotechnical Commission, Geneva, Switz., 22 May 2003.
• ISO 7240-19, Fire Detection and Alarm Systems — Part 19: Design, Installation, Commissioning and Service
of Sound Systems for Emergency Purposes, International Organization for Standardization, Geneva, Switz., 1st
edition, 15 Aug 2007.
• NEMA Standards Publication SB 50-2008, Emergency Communications Audio Intelligibility Applications
Guide, National Electrical Manufacturers Association, Rosslyn VA, 2008.
• Annex A.7.4.1.4 of NFPA 72, "National Fire Alarm and Signaling Code".
A-3.2.4.23.(2) Voice Intelligibility.
Common intelligibility scale measuring requirements and guidance on the proper design of intelligible voice and alarm
systems can be found in Annex A7.4.1.4 of NFPA 72, “National Fire Alarm and Signaling Code”.
RATIONALE FOR CHANGE
Problem/General Background
The current growing body of knowledge and experience is showing that CIS level of 0.70 is an incorrect and
unachievable target to be placed in the Code.
Justification/Explanation
This proposed change would harmonize requirements with the model National Building Code of Canada.
The previous intent that the CIS level of 0.70 be attained by the Voice Communication System is proving to be an
incorrect and unachievable target to be placed in the Code. The current growing body of knowledge and
experience is showing that the level may only be able to be met, in certain areas, using various criteria, but
certainly not throughout a building as stipulated. In the current edition of the NFPA 72 Standard, the 0.70 target
has thus been changed from being a mandatory level to that of a voluntary target level with guidance information.
Cost/Benefit Implications
None.
Enforcement Implications
This will simplify the application of the Code requirements.
Who is Affected
Designers, building officials.
Building and Development Branch
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Objective Based Analysis
Provision
Objective/Functional Statement
Division B 3.2.4.23.
(1)
[F12,F11-OS3.7]
(2)
[F11-OS1.5]
(2) 3
[F11-OS1.5]
(3) 4
[F11-OS1.5][F13-OS1.4,OS1.5]
(4) 5
[F11-OS1.5]
(5) 6
[F12-OS3.7]
(6) 7
[F11-OS1.5]
(7) 8
[F11-OS1.5]
(8) 9
[F11-OS1.5]
(9) 10
OTHER SUPPORTING MATERIALS
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