Construction articles, spatial separation and fire alarm systems (Building Services)

Last updated October 22, 2026

Values this chapter turns on

total occupant load that triggers a fire alarm: 300 persons; total occupant load that triggers a fire alarm
unacknowledged alert becomes an alarm, 2-stage: 5 min; unacknowledged alert becomes an alarm, 2-stage
min alarm level in a residential sleeping room: 75 dBA; min alarm level in a residential sleeping room
max annunciator zone, unsprinklered building: 2,000 m²; max annunciator zone, unsprinklered building

This section is the heart of the services side of Part 3. The construction articles tell you whether a building must be sprinklered, and Subsection 3.2.4. tells you when a fire alarm system is needed, what kind, and what it must do. A services examiner expects you to move quickly between the two: find the right construction article, note whether it says "sprinklered", then go to 3.2.4.1. to see whether an alarm follows.

How the construction articles are organized

Articles 3.2.2.20. to 3.2.2.92. run in a fixed order: by major occupancy (Group A Division 1 first, Group F Division 3 last), and inside each group from the least restrictive "any height, any area, sprinklered" article down to the smallest buildings. Every heading follows the same pattern, so read the heading first:

Heading part	What it tells you	Example
Group and division	Which major occupancy the article covers	"Group D"
Height limit	Maximum building height in storeys	"up to 6 Storeys"
Area limit	"Any Area", "Increased Area", or a table of areas	"Table 3.2.2.54."
"Sprinklered"	The building must be sprinklered throughout to use it	"Sprinklered"
Construction words	Noncombustible, encapsulated mass timber, or a free choice	"Noncombustible Construction"

The first article of each group is the fallback: for Group A Division 1 it is Article 3.2.2.20., which demands noncombustible construction, sprinklers throughout, and 2 h floor fire separations OBC Div. B 3.2.2.20.. The later articles relax this for smaller buildings.

Areas come in two forms. Some articles state the areas in the text, such as the sprinklered Group D article, where the maximum building area drops as storeys are added (for example 4,500 m² at 4 storeys) and the height is also capped at 18 m to the uppermost floor OBC Div. B 3.2.2.60.. Others point to a table that gives areas for buildings facing 1, 2 or 3 streets, such as Article 3.2.2.50. for noncombustible Group C buildings up to 4 storeys OBC Div. B 3.2.2.50. or Article 3.2.2.80. for small Group F Division 2 buildings OBC Div. B 3.2.2.80..

A few articles have their own service twists. Group A Division 4 (outdoor seating) needs sprinklers in occupied spaces under tiers of seats OBC Div. B 3.2.2.35.. An open-air storage garage up to 22 m high may have unrated assemblies if it is noncombustible, not more than 10,000 m², and every part of each floor is within 60 m of an exterior wall opening OBC Div. B 3.2.2.92..

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Limiting distance and unprotected openings

Limiting distance is measured at right angles from the exposing building face to the property line, the centre line of a street, lane or public thoroughfare, or an imaginary line between two buildings on one property definition. Article 3.2.3.1. sets the permitted area of unprotected openings by table: one pair of tables for faces that are not sprinklered and another for sprinklered fire compartments in a building sprinklered under Section 3.2 OBC Div. B 3.2.3.1.. The percentage is the total opening area divided by the area of the exposing building face.

Two service-related rules matter here. First, in an unsprinklered building with a limiting distance of 2 m or less, individual openings are capped in size, and at 1.2 m or more you may use the formula Area = 0.24((2 × LD) − 1.2)². Second, if any storey is unsprinklered and the fire department cannot reach the building within 10 min of the alarm, the required limiting distance is doubled.

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Fire alarm systems: where required and types

Article 3.2.4.1. has two triggers OBC Div. B 3.2.4.1.:

Sprinklers. A building with an automatic sprinkler system needs a fire alarm system, except an NFPA 13D building or one with fewer than 9 sprinklers fed from the domestic water system.
Unsprinklered buildings over a threshold. Our summary of the main occupant load triggers:

Unsprinklered building contains	Alarm needed when
Total occupant load	more than 300
Occupant load above or below the first storey	more than 150
School, college or child care facility	occupant load more than 40
Low or medium hazard industrial, above or below first storey	occupant load more than 75
High hazard industrial	occupant load more than 25
Residential sleeping accommodation	more than 10 persons
Storeys (counting those below the first storey)	more than 3

Exceptions follow: small residential buildings where not more than 4 suites share a means of egress or each suite exits directly outside, low hotels with exterior exit facilities, and unsprinklered open-air storage garages under Article 3.2.2.92.

Once required anywhere, the alarm goes throughout the building, and one system serves all major occupancies OBC Div. B 3.2.4.2.. The exception is a portion not more than 3 storeys high cut off by a 1 h vertical fire separation with no openings other than for piping, tubing, wiring and enclosed noncombustible raceways.

Type of system OBC Div. B 3.2.4.3.: single-stage for Group F Division 1 and for elementary and secondary schools (other than a special needs facility); 2-stage for Group B (with a choice for low Group B Division 3 buildings); either type elsewhere. In a 2-stage system the alert must turn into an alarm automatically if not acknowledged within 5 min, except in Group B Division 2 OBC Div. B 3.2.4.4.. Alarm signals cannot silence automatically before 5 min (no annunciator required) or 20 min (all other buildings) OBC Div. B 3.2.4.6.. Installation follows CAN/ULC-S524 and verification follows CAN/ULC-S537 OBC Div. B 3.2.4.5.; the exam asks which standard, not what is in it.

An annunciator goes near the entrance used by firefighters, with zones not more than 2,000 m² in an unsprinklered building and not more than one storey OBC Div. B 3.2.4.8.. It is waived in an unsprinklered building of not more than 3 storeys and not more than 2,000 m² aggregate area.

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Detectors, smoke alarms, signals and voice communication

In an unsprinklered building with a required alarm, fire detectors go in storage rooms, service rooms, janitors' rooms, hazardous substance rooms, elevator hoistways, residential laundry rooms and hazardous school classrooms OBC Div. B 3.2.4.10.. Sprinklered floor areas are exempt. Wherever a fire alarm system is installed, sprinklered or not, smoke detectors are needed in places such as Group B sleeping rooms, exit stair shafts, elevator machine rooms and public corridors in Group C OBC Div. B 3.2.4.11..

Audibility numbers OBC Div. B 3.2.4.18.: at least 75 dBA in a residential sleeping room with doors closed, at least 65 dBA and 10 dBA above ambient elsewhere, and not more than 110 dBA at 3 m. Alarm signals use the temporal pattern of ISO 8201.

Smoke alarms OBC Div. B 3.2.4.20. go in every dwelling unit (one per storey, in each sleeping room and between bedrooms and the rest of the storey), are hard-wired with battery backup good for 7 days plus 4 minutes of alarm, are interconnected within the unit, and have a 10 min silencing device. Visual components in sleeping rooms need at least 175 cd.

Voice communication: a two-way system (when required by 3.2.6. and elsewhere) allows silencing of signals only after 30 s (10 s for staffed hospitals) OBC Div. B 3.2.4.22.. A one-way system is needed where a 2-stage system serves an occupant load over 1,000, except Group B Division 1 and Group F Division 1 OBC Div. B 3.2.4.23..

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Common traps

Forgetting that "sprinklered" in an article heading automatically pulls in a fire alarm system through 3.2.4.1.(1).
Counting storeys for the alarm trigger without storeys below the first storey. The code counts them.
Mixing the silencing times: 5 min alert-to-alarm in a 2-stage system, versus 5 or 20 min before an alarm can silence automatically.
Treating CAN/ULC-S524 as the verification standard. S524 is installation; S537 is verification.
Assuming smoke alarms may run on batteries alone. Required ones need a permanent electrical connection.

Chapter review

Chapter at a glance

One line per section: the idea to carry into the exam. Then the answers that most often catch candidates out.

Chapter at a glance: the key idea in each section
Section	Key idea
How the construction articles are organized	Articles 3.2.2.20. to 3.2.2.92. run in a fixed order: by major occupancy (Group A Division 1 first, Group F Division 3 last), and inside each group from the least restrictive "any…
Limiting distance and unprotected openings	Limiting distance is measured at right angles from the exposing building face to the property line, the centre line of a street, lane or public thoroughfare, or an imaginary line…
Fire alarm systems: where required and types	Exceptions follow: small residential buildings where not more than 4 suites share a means of egress or each suite exits directly outside, low hotels with exterior exit facilities…
Detectors, smoke alarms, signals and voice communication	In an unsprinklered building with a required alarm, fire detectors go in storage rooms, service rooms, janitors' rooms, hazardous substance rooms, elevator hoistways, residential…

How the construction articles are organized
Articles 3.2.2.20. to 3.2.2.92. run in a fixed order: by major occupancy (Group A Division 1 first, Group F Division 3 last), and inside each group from the least restrictive "any…
Limiting distance and unprotected openings
Limiting distance is measured at right angles from the exposing building face to the property line, the centre line of a street, lane or public thoroughfare, or an imaginary line…
Fire alarm systems: where required and types
Exceptions follow: small residential buildings where not more than 4 suites share a means of egress or each suite exits directly outside, low hotels with exterior exit facilities…
Detectors, smoke alarms, signals and voice communication
In an unsprinklered building with a required alarm, fire detectors go in storage rooms, service rooms, janitors' rooms, hazardous substance rooms, elevator hoistways, residential…

Usual exam traps

Forgetting that "sprinklered" in an article heading automatically pulls in a fire alarm system through 3.2.4.1.(1).
Counting storeys for the alarm trigger without storeys below the first storey. The code counts them.
Mixing the silencing times: 5 min alert-to-alarm in a 2-stage system, versus 5 or 20 min before an alarm can silence automatically.
Treating CAN/ULC-S524 as the verification standard. S524 is installation; S537 is verification.
Assuming smoke alarms may run on batteries alone. Required ones need a permanent electrical connection.

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Questions on Construction articles, spatial separation and fire alarm (3.2.2 to 3.2.4), in the exam format, every answer explained and cited to its article. Sign in to start; a free account gets the free questions.

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Code cited in this chapter

Based on the official 2024 Building Code Compendium on ontario.ca.

OBC Div. B 3.2.2.20. Group A, Division 1, Any Height, Any Area, Sprinklered
(1)Except as permitted by Articles 3.2.2.21. and 3.2.2.22., a building classified as Group A, Division 1 shall conform to Sentence (2).
(2)Except as permitted by Article 3.2.2.16., the building referred to in Sentence (1) shall be of noncombustible construction, and
(a)except as permitted by Sentences 3.2.2.7.(1) and 3.2.2.18.(2), the building shall be sprinklered throughout,
(b)floor assemblies shall be fire separations with a fire-resistance rating not less than 2 h,
(c)mezzanines shall have a fire-resistance rating not less than 1 h, and
(d)loadbearing walls, columns and arches shall have a fire-resistance rating not less than that required for the supported assembly.
Open OBC Div. B 3.2.2.20. in the code viewer
OBC Div. B 3.2.2.60. Group D, up to 6 Storeys, Sprinklered
(1)A building classified as Group D is permitted to conform to Sentence (2) provided
(a)it is sprinklered throughout,
(b)it is not more than 6 storeys in building height,
(c)it has a height of not more than 18 m measured between the floor of the first storey and the uppermost floor level that does not serve a rooftop enclosure for elevator machinery, a stairway or a service room used only for service to the building, and
(d)it has a building area of not more than
(i)18,000 m² if 1 storey in building height,
(ii)9,000 m² if 2 storeys in building height,
(iii)6,000 m² if 3 storeys in building height,
(iv)4,500 m² if 4 storeys in building height,
(v)3,600 m² if 5 storeys in building height, or
(vi)3,000 m² if 6 storeys in building height.
(2)The building referred to in Sentence (1) is permitted to be of combustible construction or noncombustible construction used singly or in combination, and
(a)floor assemblies shall be fire separations with a fire-resistance rating not less than 1 h,
(b)roof assemblies shall have a fire-resistance rating not less than 1 h,
(c)except as provided by Sentence (3), where the roof assembly has a height greater than 25 m measured from the floor of the first storey to the highest point of the roof assembly, the roof assembly shall be constructed of noncombustible construction or fire-retardant-treated wood conforming to Article 3.1.4.5.,
(d)mezzanines shall have a fire-resistance rating not less than 1 h, and
(e)loadbearing walls, columns and arches shall have a fire-resistance rating not less than that required for the supported assembly.
(3)Where buildings conforming to Sentence (2) include non-contiguous roof assemblies at different elevations, the roof assemblies are permitted to be evaluated separately to determine which ones are required to be constructed in accordance with Clause (2)(c).
(4)Group A, Division 2 major occupancies, Group E major occupancies, Group F, Division 2 and 3 major occupancies and storage garages located in a building or part thereof within the scope of this Article are permitted to be constructed in accordance with this Article, provided
(a)the Group A, Division 2 major occupancy, Group E major occupancy and Group F, Division 2 or 3 major occupancy are located below the third storey, and
(b)storage garages are located below the fourth storey. (See also Article 4.4.2.1.)(See Note A-3.2.2.51.(5) and 3.2.2.60.(4))
Open OBC Div. B 3.2.2.60. in the code viewer
OBC Div. B 3.2.2.50. Group C, up to 4 Storeys, Noncombustible Construction
(1)A building classified as Group C, other than a retirement home, is permitted to conform to Sentence (2) provided
(a)it is not more than
(i)3 storeys in building height, or
(ii)4 storeys in building height provided there is not more than one dwelling unit above another dwelling unit, and vertical fire separations of adjacent dwelling units conform to Sentence (4), and
(b)it has a building area not more than the value in Table 3.2.2.50.
(2)The building referred to in Sentence (1) shall be of noncombustible construction, and
(a)except as permitted by Sentence (3), floor assemblies shall be fire separations with a fire-resistance rating not less than 1 h,
(b)mezzanines shall have a fire-resistance rating not less than 1 h,
(c)roof assemblies shall have a fire-resistance rating not less than 1 h, and
(d)loadbearing walls, columns and arches shall have a fire-resistance rating not less than that required for the supported assembly.
(3)In a building that contains dwelling units that have more than one storey, subject to the requirements of Sentence 3.3.4.2.(3), the floor assemblies, including floors over basements, which are entirely contained within these dwelling units, shall have a fire-resistance rating not less than 1 h but need not be constructed as fire separations.
(4)The dwelling units described in Subclause (1)(a)(ii) shall be separated by continuous vertical fire separations that extend through all storeys and service spaces of the separated portions.
Open OBC Div. B 3.2.2.50. in the code viewer
OBC Div. B 3.2.2.80. Group F, Division 2, up to 2 Storeys
(1)A building classified as Group F, Division 2 is permitted to conform to Sentence (2) provided
(a)it is not more than 2 storeys in building height, and
(b)it has a building area not more than the value in Table 3.2.2.80.
(2)The building referred to in Sentence (1) is permitted to be of combustible construction or noncombustible construction used singly or in combination, and
(a)floor assemblies shall be fire separations and, if of combustible construction, shall have a fire-resistance rating not less than 45 min, and
(b)loadbearing walls, columns and arches supporting an assembly required to have a fire-resistance rating shall
(i)have a fire-resistance rating not less than 45 min, or
(ii)be of noncombustible construction.
Open OBC Div. B 3.2.2.80. in the code viewer
OBC Div. B 3.2.2.35. Group A, Division 4
(1)Except as permitted by Sentences (2) and (3), a building classified as Group A, Division 4 shall be of noncombustible construction.
(2)Roof assemblies and supporting arches and columns are permitted to be of heavy timber construction.
(3)A building classified as Group A, Division 4 is permitted to be of combustible construction provided
(a)the occupant load is less than 1,500, and
(b)the building has a limiting distance not less than 6 m.
(4)Sprinklers shall be installed in all spaces below tiers of seats in a building classified as Group A, Division 4 if those spaces are used for occupancy. (See Note A-3.2.2.35.(4))
Open OBC Div. B 3.2.2.35. in the code viewer
OBC Div. B 3.2.2.92. Group F, Division 3, Storage Garages up to 22 m High
(1)A building used as a storage garage with all storeys constructed as open-air storeys and having no other occupancy above it is permitted to have its floor, wall, ceiling and roof assemblies constructed without a fire-resistance rating provided it is
(a)of noncombustible construction,
(b)not more than 22 m high, measured between grade and the ceiling level of the top storey,
(c)not more than 10,000 m² in building area, and
(d)designed so that every portion of each floor area is within 60 m of an exterior wall opening.
Open OBC Div. B 3.2.2.92. in the code viewer
OBC Div. A 1.4.1.2.(1) Limiting distance
Limiting distance means the distance from an exposing building face to a property line, the centre line of a street, lane or public thoroughfare, or to an imaginary line between 2 buildings or fire compartments on the same property, measured at right angles to the exposing building face.
Open OBC Div. A 1.4.1.2.(1) in the code viewer
OBC Div. B 3.2.3.1. Limiting Distance and Area of Unprotected Openings
(1)Except as permitted by Articles 3.2.3.10. to 3.2.3.12., the area of unprotected openings in an exposing building face for the applicable limiting distance shall be not more than the value determined in accordance with
(a)Table 3.2.3.1.-B or Table 3.2.3.1.-C for an exposing building face conforming to Article 3.2.3.2. of a building or fire compartment which is not sprinklered, or
(b)Table 3.2.3.1.-D or Table 3.2.3.1.-E for an exposing building face conforming to Article 3.2.3.2. of a sprinklered fire compartment that is part of a building which is sprinklered in conformance with Section 3.2. (See Note A-3) (See also Article 3.1.18.3.)
(2)The area of the unprotected openings in an exposing building face shall be the aggregate area of unprotected openings expressed as a percentage of the area of the exposing building face in Table 3.2.3.1.-B, 3.2.3.1.-C, 3.2.3.1.-D or 3.2.3.1.-E. (See Sentence 3.2.3.2.(1))
(3)For the purpose of determining the type of construction and cladding and the fire-resistance rating of an exterior wall,
(a)the exposing building face shall be taken as the projection of the exterior wall onto a vertical plane located so that no portion of the exterior wall of the building or of a fire compartment, if the fire compartment complies with the requirements of Article 3.2.3.2., is between the vertical plane and the line to which the limiting distance is measured, and
(b)the area of unprotected openings shall be determined from Table 3.2.3.1.-B, 3.2.3.1.-C, 3.2.3.1.-D or 3.2.3.1.-E.
(4)For the purpose of determining the actual percentage of unprotected openings permitted in an exterior wall, the location of the exposing building face is permitted to be taken at a vertical plane located so that there are no unprotected openings between the vertical plane and the line to which the limiting distance is measured. (See Note A-3.2.3.1.(4))
(5)Except for buildings that are sprinklered, where the limiting distance is 2 m or less, individual unprotected openings in an exposing building face shall be no greater than
(a)the area stated in Table 3.2.3.1.-A, or
(b)where the limiting distance equal to or greater than 1.2 m, the area calculated by
Area =
Area = 0.24[((2 × LD) − 1.2)^2]
where
Area = area of the unprotected opening, and
LD = limiting distance.
(6)The spacing between individual unprotected openings described in Sentence (5) that serve a single room or space described in Sentence (7) shall not be less than
(a)2 m horizontally of another unprotected opening that is on the same exposing building face and serves the single room or space, or
(b)2 m vertically of another unprotected opening that serves the single room or space, or another room or space on the same storey.
(7)For the purpose of Sentence (6), "single room or space" means a room or space that
(a)is not divided by a wall,
(b)is divided by
(i)a wall that extends less than 1.5 m from the interior face of the exterior wall, or
(ii)a partial height wall, or
(c)consists of two or more stacked spaces that are on the same storey.
(8)If a building has any storey that is not sprinklered and firefighting facilities cannot reach it within 10 min of the alarm being received, the required limiting distance shall be doubled.
(9)If the surface temperature on the unexposed surface of a wall assembly exceeds the temperature limit of a standard fire test as permitted by Article 3.1.7.2., an allowance shall be made for the radiation from the hot unexposed wall surface by adding an equivalent area of unprotected opening to the area of actual openings as follows:
A_C = A + (A_E × F_EO)
where
A_C = corrected area of unprotected openings including actual and equivalent openings,
A = actual area of unprotected openings,
A_F = area of exterior surface of the exposing building face, exclusive of openings, on which the temperature limit of the standard test is exceeded, and
F_EO = an equivalent opening factor derived from the following expression:
F_EO = ((T_u + 273)^4)/((T_e + 273)^4)
T_u = average temperature in degrees Celsius of the unexposed wall surface at the time the required fire-resistance rating is reached under test conditions,
T_e = 892°C for a fire-resistance rating not less than 45 min, 927°C for a fire-resistance rating not less than 1 h, and 1,010°C for a fire-resistance rating not less than 2 h.
(10)Unless a closure used to protect an opening in an exposing building face has a protective performance equivalent to that required for the wall assembly in which it is located, an equivalent area of unprotected opening, determined in accordance with the procedures of Sentence (9) shall be added to the greater of
(a)the actual area of unprotected openings, or
(b)the corrected area of unprotected openings.
(11)The required limiting distance for an exposing building face is permitted to be measured to a point beyond the property line that is not the centre line of a street, lane or public thoroughfare if
(a)the owners of the properties on which the limiting distance is measured and the municipality enter into an agreement in which such owners agree that,
(i)each owner covenants that, for the benefit of land owned by the other covenantors, the owner will not construct a building on his or her property unless the limiting distance for exposing building faces in respect of the proposed construction is measured in accordance with the agreement,
(ii)the covenants contained in the agreement are intended to run with the lands, and the agreement shall be binding on the parties and their respective heirs, executors, administrators, successors and assigns,
(iii)the agreement shall not be amended or deleted from title without the consent of the municipality, and
(iv)they will comply with such other conditions as the municipality considers necessary, including indemnification of the municipality by the other parties, and
(b)the agreement referred to in Clause (a) is registered against the title of the properties to which it applies.
(12)Where an agreement referred to in Sentence (11) is registered against the title of a property, the limiting distance for exposing building faces shall be measured to the point referred to in the agreement.
Open OBC Div. B 3.2.3.1. in the code viewer

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OBC Div. B 3.2.4.1. Determination of Requirement for a Fire Alarm System
(1)Except as permitted in Sentences (2) and (3), a fire alarm system shall be installed in buildings in which an automatic sprinkler system is installed.
(2)Buildings in which a sprinkler system is installed in accordance with NFPA 13D, "Standard for the Installation of Sprinkler Systems in One- and Two-Family Dwellings and Manufactured Homes," need not comply with Sentence (1).
(3)Buildings that contain fewer than 9 sprinklers conforming to Sentence 3.2.5.12.(4) need not comply with Sentence (1).
(4)Except as permitted by Sentences (5), (6) and 3.2.4.2.(4), a fire alarm system shall be installed in a building that is not sprinklered throughout and that contains
(a)a contained use area,
(b)an impeded egress zone,
(c)more than 3 storeys, including storeys below the first storey,
(d)a total occupant load more than 300, other than in open air seating areas,
(e)an occupant load more than 150 above or below the first storey, other than in open air seating areas,
(f)a school, college or child care facility, including a day care facility, with an occupant load more than 40,
(g)a licensed beverage establishment or a licenced restaurant, with an occupant load more than 150,
(h)a low-hazard industrial occupancy with an occupant load more than 75 above or below the first storey,
(i)a medium-hazard industrial occupancy with an occupant load more than 75 above or below the first storey,
(j)a residential occupancy with sleeping accommodation for more than 10 persons,
(k)a high-hazard industrial occupancy with an occupant load more than 25,
(l)an occupant load more than 300 below an open air seating area,
(m)a care and treatment occupancy for more than 10 persons receiving care or treatment, or
(n)a care occupancy for more than 10 persons receiving care.
(4.1)A fire alarm system is not required in a hotel 3 storeys or less in building height provided each suite has direct access to an exterior exit facility leading to ground level.
(5)A fire alarm system is not required in a residential occupancy that is not sprinklered, where
(a)not more than 4 suites share a common means of egress, or
(b)each suite has direct access to an exterior exit facility leading to ground level.
(6)A fire alarm system is not required in a storage garage conforming to Article 3.2.2.92. that is contained in a building that is not sprinklered provided there are no other occupancies in the building.
Open OBC Div. B 3.2.4.1. in the code viewer
OBC Div. B 3.2.4.2. Continuity of Fire Alarm System
(1)Except as permitted by Sentence (6), if there are openings through a firewall, other than those for piping, tubing, wiring and totally enclosed noncombustible raceways, the requirements in this Subsection shall apply to the floor areas on both sides of the firewall as if they were in the same building.
(2)Except as permitted by Sentence (4), if a building contains more than one major occupancy and a fire alarm system is required, a single system shall serve all occupancies.
(3)Except as permitted by Sentence (4), if a fire alarm system is required in any portion of a building, it shall be installed throughout the building.
(4)Except as required by Sentence (5), the requirements in this Subsection are permitted to be applied to each portion of a building not more than 3 storeys in building height, in which a vertical fire separation having a fire-resistance rating not less than 1 h separates the portion from the remainder of the building as if it were a separate building, provided there are no openings through the fire separation, other than those for piping, tubing, wiring and totally enclosed noncombustible raceways.
(5)The permission in Sentence (4) to consider separated portions of a building as separate buildings does not apply to service rooms and storage rooms.
(6)Buildings interconnected by walkways permitted in Articles 3.2.3.19. and 3.2.3.20. or by vestibules provided in conformance with Article 3.2.6.3. shall be treated as separate buildings for the purpose of fire alarm installation required by this Subsection.
Open OBC Div. B 3.2.4.2. in the code viewer
OBC Div. B 3.2.4.3. Types of Fire Alarm Systems
(1)A fire alarm system shall be
(a)a single-stage system in a Group F, Division 1 occupancy,
(b)except as permitted in Clause (c), a 2-stage system in a Group B occupancy,
(c)a single- or 2-stage system in a Group B, Division 3 occupancy where the building is 3 storeys or less in building height,
(d)a single-stage system in elementary and secondary schools, except for a special needs facility, and
(e)a single- or 2-stage system in all other cases.
Open OBC Div. B 3.2.4.3. in the code viewer
OBC Div. B 3.2.4.4. Description of Fire Alarm Systems
(1)A single-stage fire alarm system shall, upon the operation of any manual station, waterflow detecting device, or fire detector, cause an alarm signal to sound on all audible signal devices in the system. (See Note A-3.2.4.4.(1))
(2)A 2-stage fire alarm system shall
(a)cause an alert signal to sound upon the operation of any manual station, waterflow detecting device, or fire detector,
(b)except for a Group B, Division 2 occupancy, automatically cause an alarm signal to sound if the alert signal is not acknowledged within 5 min of its initiation,
(c)have manual stations, each of which is equipped so that the use of a key or other similar device causes an alarm signal to sound that continues to sound upon removal of the key or similar device from the manual station, and (See Note A-3.2.4.4.(2)(c))
(d)in a building containing a hotel,
(i)cause an alarm signal to sound in the initiating fire zone in the hotel, and
(ii)cause an alert signal to sound throughout the hotel and such parts of the building as is necessary to alert hotel staff. (See Note A-3.2.4.4.(2))
(3)A 2-stage fire alarm system is permitted to be zone coded so that, upon the operation of any manual station, waterflow detecting device, or fire detector,
(a)a coded alert signal is sounded indicating the zone of alarm initiation,
(b)the coded alert signal is repeated in its entirety not less than 4 times, and
(c)a continuous alert signal is sounded upon completion of the coded signals referred to in Clause (b) and Sentence (4).
(4)If a second manual station, waterflow detecting device, or fire detector is operated in a fire alarm system with zone coding as permitted by Sentence (3), in a zone other than that for which the first alert signal was sounded, the coded alert signal for the first zone shall be completed before the coded alert signal for the second zone is repeated not less than 4 times.
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OBC Div. B 3.2.4.6. Silencing of Alarm Signals
(1)Except as permitted by Sentence (3), a fire alarm system shall be designed so that when an alarm signal is actuated, it cannot be silenced automatically before a period of time has elapsed that is not less than
(a)5 min for a building not required to be equipped with an annunciator, and
(b)20 min for any other building.
(2)Except as permitted by Sentences 3.2.4.18.(8) and Sentences 3.2.4.22.(2) and (3), a fire alarm system shall not incorporate manual silencing switches other than those installed inside the fire alarm control unit. (See Note A-3.2.4.6.(2))
(3)Except as provided by Clause 3.2.4.22.(3)(a), in a care and treatment occupancy an alert signal is permitted to be silenced automatically after 1 min.
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OBC Div. B 3.2.4.5. Installation and Verification of Fire Alarm Systems
(1)Fire alarm systems, including those with voice communication capability where provided, shall be installed in conformance with CAN/ULC-S524, "Standard for Installation of Fire Alarm Systems."
(2)Fire alarm systems shall be verified in conformance with CAN/ULC-S537, "Verification of Fire Alarm Systems," to ensure satisfactory operation.
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OBC Div. B 3.2.4.8. Annunciator and Zone Indication
(1)Except as permitted by Sentences (3) to (5), an annunciator shall be installed in close proximity to a building entrance that faces a street or an access route for fire department vehicles that complies with Sentence 3.2.5.5.(1).
(2)Except as permitted by Sentence (6), the annunciator required by Sentence (1) shall have separate zone indication of the actuation of the alarm initiating devices in each
(a)floor area so that the area of coverage for each zone in a building that is not sprinklered is not more than 2,000 m²,
(b)floor area so that the area of coverage for each zone is neither
(i)more than one storey, nor
(ii)more than the system area limits as specified in NFPA 13, "Standard for the Installation of Sprinkler Systems,"
(c)shaft required to be equipped with fire detectors,
(d)air-handling system required to be equipped with smoke detectors,
(e)fire extinguishing system required by NFPA 96, "Standard for Ventilation Control and Fire Protection of Commercial Cooking Operations,"
(f)contained use area,
(g)impeded egress zone, and
(h)fire compartment required by Sentence 3.3.3.5.(2) or Sentence 3.3.4.11.(2).(See Note A-3.2.4.8.(2))
(3)An annunciator need not be provided for a fire alarm system if not more than one zone indicator is required in Sentence (2).
(4)If an annunciator is not installed as part of a fire alarm system in conformance with Sentence (1), a visible and audible trouble signal device shall be provided inside the main entrance of the building.
(5)The requirements in Sentence (1) are waived in a building
(a)in which an automatic sprinkler system is not installed,
(b)that has an aggregate area for all storeys of not more than 2,000 m², and
(c)that is not more than 3 storeys in building height.
(6)The area limits of Clause (2)(a) are waived for an interior undivided open space used as an arena, a rink or a swimming pool provided that other spaces in the building that are separated from the open space are individually zoned in accordance with the requirements of Sentence (2).
(7)A fire alarm control unit installed in close proximity to a building entrance that faces a street or an access route for fire department vehicles that complies with Sentence 3.2.5.5.(1), is deemed to satisfy the requirement for an annunciator provided all indicators required for an annunciator or trouble signal device are included on the control unit. (See Note A-3.2.4.8.(7))
(8)In a building containing a hotel in which a trouble signal sounding device has a silencing switch, a trouble light shall be installed in
(a)the main reception area serving the hotel, or
(b)another continually-supervised location.
(9)In a long-term care home, a remote audiovisual fire alarm trouble signal shall be located at the main nursing station.
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OBC Div. B 3.2.4.10. Fire Detectors
(1)Fire detectors required by this Code shall be connected to the fire alarm system.
(2)Except as permitted by Sentence (3), if a fire alarm system is required in a building that is not sprinklered, fire detectors shall be installed in the following spaces:
(a)storage rooms not within dwelling units,
(b)service rooms not within dwelling units,
(c)janitors' rooms,
(d)rooms in which hazardous substances are to be used or stored, (See Note A-3.3.1.2.(1)),
(e)elevator hoistways or dumbwaiter shafts,
(f)laundry rooms in buildings of residential occupancy, but not those within dwelling units, and
(g)hazardous classrooms and change rooms in elementary or secondary schools.
(3)Fire detectors required by Sentence (2) need not be provided within floor areas that are sprinklered.
(4)Fire detectors required by Sentence (2) shall be installed in elevator hoistways and dumbwaiter shafts where a sprinkler system is not installed within the hoistway or shaft.
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OBC Div. B 3.2.4.11. Smoke and Heat Detectors
(1)If a fire alarm system is installed, smoke detectors shall be installed in
(a)each sleeping room and each corridor serving as part of a means of egress from sleeping rooms in portions of a building classified as Group B major occupancy,
(b)each room in a contained use area and corridors serving those rooms,
(c)each corridor in portions of a building classified as Group A, Division 1 major occupancy,
(d)each public corridor in portions of a building classified as Group C major occupancy,
(e)each exit stair shaft, other than those serving only a Group A, Division 4 major occupancy or an open storage garage.
(f)the vicinity of draft stops required by Article 3.2.8.6.,
(g)each elevator machine room, and
(h)each corridor serving classrooms in elementary and secondary schools.(See Note A-3.2.4.11.(1))
(2)In a floor area containing a hotel, where a fire alarm system is installed and the floor area is not sprinklered, heat detectors shall be installed in every room in a suite and in every room not located in a suite other than washrooms within a suite, saunas, refrigerated areas and swimming pools.
(3)Smoke detectors required in sleeping rooms of a care, care and treatment or detention occupancy shall, upon actuation, provide an audible and visible signal to staff serving those rooms so that the room or location containing the smoke detector can be easily identified. (See Note A-3.2.4.11.(3))
(4)Smoke detectors required in Clause (1)(g) shall, upon actuation, recall the elevators served by the elevator machine room in which the smoke detector is installed.
(5)Except as permitted in Sentences (6) and (7), smoke detectors installed in buildings required to be equipped with a fire alarm system shall be located near the entrance to walkways described in Articles 3.2.3.19. and 3.2.3.20. or vestibules provided in conformance with Article 3.2.6.3.
(6)Smoke detectors installed at the entrance to the walkways in conformance with Article 3.1.8.14. shall be deemed to meet the requirements of Sentence (5).
(7)Smoke detectors required by Sentence (5) may be replaced with fire detectors in Group F occupancies where the smoke detectors may be subjected to false alarms due to the activities within the building.
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OBC Div. B 3.2.4.18. Audibility of Alarm Systems
(1)Except as permitted by Sentence 3.2.4.19.(2) and except as required by Clause 3.2.4.4.(2)(d), audible signal devices forming part of a fire alarm system shall be installed in a building so that
(a)alarm signals are clearly audible throughout the floor area, and
(b)alert signals are clearly audible in continuously staffed locations, and where there are no continuously staffed locations, throughout the floor area. (See Note A-3.2.4.18.(1))
(2)The sound pattern of an alarm signal shall conform to the temporal pattern defined in Clause 4.2 of ISO 8201, "Acoustics Audible emergency evacuation signal." (See Note A-3.2.4.18.(2))
(3)The sound patterns of alert signals shall be significantly different from the temporal patterns of alarm signals. (See Note A-3.2.4.18.(3))
(4)In all normally occupied spaces, the fire alarm signal sound pressure level
(a)shall be not more than 110 dBA when measured at a distance of 3 m from the device, or
(b)is permitted to be more than 100 dBA provided the sound pressure level measured 2,000 mm above floor level is not more than 100 dBA. (See Note A-3.2.4.18.(4))
(5)The sound pressure level in a sleeping room from a fire alarm audible signal device shall be not less than 75 dBA in a building of residential occupancy when any intervening doors between the device and the sleeping room are closed. (See Note A-3.2.4.18.(5))
(6)Audible signal devices in sleeping rooms in a building of residential or care occupancy shall emit a low frequency signal. (See Note A-3.2.4.18.(6))
(7)Except as required by Sentence (5), the sound pressure level from a fire alarm system's audible signal device within a floor area shall be not less than 10 dBA above the ambient noise level and not less than 65 dBA, when any intervening doors between the device and the rest of the floor area are closed.
(8)Except as permitted by Sentence (12), audible signal devices located within a dwelling unit shall include a means for them to be manually silenced for a period of not more than 10 min, after which time the devices shall restore themselves to normal operation. (See Note A-3.2.4.18.(8))
(9)Audible signal devices within a dwelling unit or a suite of residential occupancy shall be connected to the fire alarm system
(a)in a manner such that a single open circuit at one device will not impair the operation of other audible signal devices on that same circuit that serve the other dwelling units or suites of residential occupancy, or
(b)on separate signal circuits that are not connected to the devices in any other dwelling unit, public corridor or suite of residential occupancy. (See Note A-3.2.4.18.(9) and (10))
(10)In a building or part thereof classified as a residential occupancy,
(a)separate circuits shall be provided for audible signal devices on each floor area, and
(b)audible signal devices within dwelling units or suites of residential occupancy shall be wired on separate signal circuits from those not within suites of residential occupancy or dwelling units. (See Note A-3.2.4.18.(9) and (10))
(11)Audible signal devices shall be installed in a service space referred to in Sentence 3.2.1.1.(8) and shall be connected to the fire alarm system.
(12)Audible signal devices within dwelling units that are wired on separate signal circuits in accordance with Clause (10)(b) need not include a means for manual signal silencing as required by Sentence (8), provided the fire alarm system includes a provision for the automatic signal silence within dwelling units, where
(a)the automatic signal silence cannot occur within the first 60 s of operation or within the zone of initiation,
(b)a subsequent alarm elsewhere in the building will reactuate the silenced audible signal devices within dwelling units,
(c)after a period of not more than 10 min, the silenced audible signal devices will be restored to continuous audible signal if the alarm is not acknowledged, and
(d)the voice communication systems referred to in Article 3.2.4.22. and 3.2.4.23. has a provision to override the automatic signal silence to allow the transmission of voice messages through silenced audible signal device circuits that serve the dwelling units. (See Note A-3.2.4.18.(12))
(13)If a 2-stage fire alarm system has been installed with an automatic signal silence as described in Sentence (12), the system shall be designed so that any silenced audible signal devices serving dwelling units are reactuated whenever an alarm signal is required to be transmitted as part of the second stage. (See Note A-3.2.4.18.(8))
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OBC Div. B 3.2.4.20. Smoke Alarms
(1)Except as provided in Article 3.2.4.21., smoke alarms shall be installed in accordance with this Article.
(2)Except as permitted by Sentence (10), smoke alarms conforming to CAN/ULC-S531, "Standard for Smoke Alarms," shall be installed in each dwelling unit and, except for care, care and treatment or detention occupancies required to have a fire alarm system, in each sleeping room not within a dwelling unit.
(3)At least one smoke alarm shall be installed on each storey and mezzanine of a dwelling unit.
(4)On any storey of a dwelling unit containing sleeping rooms, a smoke alarm shall be installed
(a)in each sleeping room, and
(b)in a location between the sleeping rooms and the remainder of the storey, and if the sleeping rooms are served by a hallway, the smoke alarm shall be located in the hallway.
(5)Reserved.
(6)A smoke alarm shall be installed on or near the ceiling.
(7)Reserved.
(8)Reserved.
(9)Except as permitted by Sentence (10), smoke alarms referred in Sentence (2) shall
(a)be installed with permanent connections to an electrical circuit,
(b)have no disconnect switch between the overcurrent device and the smoke alarm, and
(c)in case the regular power supply to the smoke alarm is interrupted, be provided with a battery as an alternative power source that can continue to provide power to the smoke alarm for a period of not less than 7 days in the normal condition, followed by 4 minutes of alarm. (See Note A-3.2.4.20.(9))
(10)Suites of residential occupancy are permitted to be equipped with smoke detectors in lieu of smoke alarms, provided the smoke detectors
(a)are capable of independently sounding audible signals with a sound pressure level between 75 dBA and 110 dBA within the individual suites, (See also Note A-3.2.4.18.(4))
(b)except as permitted by Sentence (11), are installed in conformance with CAN/ULC-S524, "Standard for the Installation of Fire Alarm Systems," and verified in conformance with CAN/ULC-S537, "Standard for the Verification of Fire Alarm Systems,"
(c)form part of the fire alarm system, and
(d)are equipped with visual signalling components that meet the requirements of Sentences (17) to (19). (See Note A-3.2.4.20.(10))
(11)Smoke detectors permitted to be installed in lieu of smoke alarms as stated in Sentence (10) are permitted to sound localized alarms within individual suites, and need not sound an alarm throughout the rest of the building.
(12)If more than one smoke alarm is required in a dwelling unit, the smoke alarms shall be interconnected so that the actuation of one smoke alarm will cause all smoke alarms within the dwelling unit to sound.
(13)A smoke alarm required by Sentence (2) shall be installed in conformance with CAN/ULC-S553, "Standard for Installation of Smoke Alarms."
(14)Except as permitted in Sentence (15), a manually operated silencing device shall be incorporated within the circuitry of a smoke alarm installed in a dwelling unit so that it will silence the signal emitted by the smoke alarm for a period of not more than 10 min, after which the smoke alarm will reset and again sound the alarm if the level of smoke in the vicinity is sufficient to reactuate the smoke alarm.
(15)Suites of residential occupancy equipped with smoke detectors installed in conformance with CAN/ULC-S524, "Standard for Installation of Fire Alarm Systems," as part of the fire alarm system in lieu of smoke alarms as permitted by Sentence (10), need not incorporate the manually operated silencing device required by Sentence (14). (See Note A-3.2.4.20.(10))
(16)The sound patterns of smoke alarms shall
(a)meet the temporal patterns of alarm signals, or (See Note A-3.2.4.18.(2))
(b)be a combination of temporal pattern and voice relay.
(17)Smoke alarms required by Sentence (2) shall have a visual signalling component conforming to the requirements in 18.5.3. (Light, Color and Pulse Characteristics) of NFPA 72, "National Fire Alarm and Signaling Code." (See Note A-3.2.4.20.(17))
(18)The visual signalling component required by Sentence (17) need not
(a)be integrated with the smoke alarm provided it is interconnected to it,
(b)be on battery backup, or
(c)have synchronized flash rates, when installed in a dwelling unit.
(19)The luminous intensity for visual signalling components required by Sentence (17) that are installed in sleeping rooms shall be a minimum of 175 cd.
(20)Smoke alarms required in suites in a retirement home or smoke detectors permitted to be installed in lieu of smoke alarms as provided in Sentence (10) shall upon actuation provide an audible and visual signal to staff serving those suites, so that the suite containing the actuated smoke alarm or smoke detector can be easily identified.
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OBC Div. B 3.2.4.22. Two-Way Voice Communication Systems
(1)A voice communication system required by Subsection 3.2.6., Clause 3.3.2.4.(14)(f) or Sentence 3.3.4.11.(12) shall
(a)consist of a two-way means of communication with the central alarm and control facility and to the mechanical control centre from each floor area, and
(b)be capable of broadcasting pre-recorded, synthesized or live messages from the central alarm and control facility that are audible and intelligible in all parts of the building, except elevator cars. (See Note A-3.2.4.22.(1)(b))
(2)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 instructions are being transmitted, but only after the alarm signal has initially sounded for not less than 30 s.
(3)The voice communication system referred to in Sentence (1) shall include a means to silence the alert signal and the alarm signal in a 2-stage fire alarm system while voice instructions 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.
(4)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 instructions to any other zone or zones in the building.
(5)The 2-way communication system referred to in Clause (1)(a) shall be installed so that emergency telephones are located in each floor area near exit stair shafts.
(6)Visible signal devices required by Sentence 3.2.4.19.(1) shall continue to emit a visible signal while voice instructions are being transmitted.
(7)Where the facility is not equipped with staff trained to provide instructions over the loudspeakers, a pre-recorded message shall be provided.
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OBC Div. B 3.2.4.23. One-Way Voice Communication Systems
(1)Except for Group B, Division 1 and Group F, Division 1 major occupancies, where a fire alarm system is required under Subsection 3.2.4., a one-way voice communication system shall be installed in buildings where a 2-stage fire alarm system is installed and whose occupant load exceeds 1,000.
(2)The one-way voice communication system required by Sentence (1) 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)except in elevator cars, designed and located so that transmitted messages are audible and intelligible in all parts of the building. (See Note A-3.2.4.22.(1)(b))
(3)Where the facility is not equipped with staff trained to provide instructions over the loudspeakers, a pre-recorded message shall be provided.
(4)The voice communication system required by Sentence (1) shall meet the silencing and transmission requirements of Sentences 3.2.4.22.(2) to (4) and (6).
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