OBC Fire Protection cheat sheet

OBC Part 1 states the objectives (fire safety, health, accessibility, etc.) and functional statements that every acceptable solution must satisfy; a design need not follow a prescriptive sentence if it demonstrably meets the objective.

Fire safety objectives are grouped under OS (safety) and OP (protection of adjacent buildings); OS1 addresses life safety, OS2 fire prevention, OS3 suppression/containment, OS4 evacuation, OS5 firefighter access.

Functional statements describe what a building must do, e.g. limit the probability of fire ignition, limit the spread of fire, limit the probability of occupants being trapped.

Objectives and functional statements are linked to each other and to the acceptable solutions in the remaining Parts; a compliance path must trace to an objective.

Alternative solutions under Part 1 must be supported by a fire safety assessment and accepted by the authority having jurisdiction.

Functional statements are expressed in terms of probability of harm, so they are qualitative rather than numeric; they set the performance target, not the dimension.

Divisions A, B, and C of the National Building Code model separate objectives/functional statements from acceptable solutions; the OBC follows the same structure.

Objectives reference occupant safety, fire prevention, and protection of adjacent buildings; they do not prescribe specific materials or ratings.

Major occupancy groups: A (assembly), B (care/detention), C (residential), D (business), E (mercantile), F (industrial, F1 high hazard, F2 medium hazard), plus Group G (storage) in the OBC.

Group F1 is high-hazard industrial (e.g. flammable liquid processing); Group F2 is medium-hazard industrial (e.g. manufacturing, repair).

Building height per OBC is the number of storeys between the lowest and highest floor levels; building area is the total floor area of all storeys above grade.

Combustible construction is permitted only within height/area limits; noncombustible construction is required where the building is too tall or too large for combustible construction.

Major occupancy classification drives fire separation requirements, exit requirements, sprinkler requirements, and fire-resistance ratings.

A building with mixed occupancies must be evaluated for the most restrictive occupancy and for separations between occupancy groups.

Group A, Division 1 (assembly with stages, e.g. theatres) carries stricter requirements than Group A, Division 2 or 3.

High-rise building is defined by height (typically more than 36 m) and triggers additional fire safety measures such as smoke control and standpipe systems.

Fire-resistance rating (FRR) is the time in minutes or hours a component maintains its separating function, structural integrity, and temperature rise limits under fire exposure.

A fire separation is a construction that resists the spread of fire; it may or may not have an FRR.

Closures in fire separations (doors, windows, dampers) must have a rating not less than the fire separation, with exceptions for limited-area glazing and self-closing doors.

Self-closing devices are required on doors in fire separations; hold-open devices must release on fire alarm.

Fire dampers are required where ducts penetrate fire separations, unless the duct is enclosed in a fire-rated shaft or the penetration is protected by other means.

FRR is determined by testing to standard fire exposure (e.g. CAN/ULC-S101) or by calculation/engineering methods acceptable to the authority.

Structural members must have FRR where required by building height, occupancy, or proximity to adjacent buildings.

Horizontal fire separations (floors) and vertical fire separations (walls) must be continuous through concealed spaces to be effective.

Limiting distance is the distance from an exposing building face to the property line, centre line of a street, or adjacent building face, measured horizontally.

The required limiting distance depends on the exposing building face's FRR, the percentage of unprotected openings, and the occupancy classification.

The spatial separation formula uses the area of unprotected openings and the limiting distance to determine permitted glazing; larger glazing requires greater distance or higher FRR.

Combustible cladding and exterior wall assemblies affect the permitted unprotected opening area.

Exposing building faces must be rated when the limiting distance is small; the closer the building to the property line, the higher the required FRR.

Openings in an exposing building face are limited by the aggregate area and by the type of glazing; sprinklered buildings may be permitted larger unprotected openings.

A building on the same property as another must be separated by a fire separation or by spatial separation from the other building.

Street centre lines and property lines define the reference for limiting distance; projections such as balconies may be measured differently.

Every floor area must have at least two exits unless the floor area is small enough to qualify for a single exit under the OBC.

Travel distance is measured along the path of egress from the most remote point to the nearest exit; maximums vary by occupancy and sprinkler protection.

Exit width is based on occupant load; the required width is a function of the number of occupants and the egress capacity per unit width.

Exit stairs must be enclosed in a shaft with an FRR where required; exit signs and emergency lighting are required in exits.

Dead-end corridors are limited in length; the maximum depends on occupancy and sprinkler protection.

Doors in means of egress must swing in the direction of travel where the occupant load is high, and must be equipped with panic hardware in certain assembly occupancies.

Exit continuity: the egress path must be continuous from any point in the floor area to a public way without passing through a room that could be locked.

Occupant load is calculated from floor area divided by the occupant load factor for the occupancy; it determines exit width, number of exits, and egress capacity.

Fire alarm systems are required in certain occupancies and building heights; the OBC references CAN/ULC-S524 for installation and CAN/ULC-S537 for verification.

Smoke detectors are required in corridors serving sleeping rooms and in certain residential suites; heat detectors are used where smoke detectors are unsuitable.

Manual pull stations must be located at each exit and along the path of egress so that no point is more than the permitted travel distance from a station.

Audible and visual signal devices must be provided; visual signals are required in sleeping rooms and in accessible areas.

Fire alarm systems must be monitored or connected to a central station where required; supervisory and trouble signals must be annunciated.

Sprinkler flow switches and valve tamper switches are supervised by the fire alarm system.

Fire alarm zones must be arranged so that a fire can be located; zoning typically follows floors or fire compartments.

Interconnection with smoke control, door release, and elevator recall must be coordinated with the fire alarm system.

Sprinkler systems are required in high-rise buildings, certain assembly occupancies, care occupancies, and where the OBC grants area/height concessions for sprinklered buildings.

Sprinkler design and installation follow NFPA 13 (or NFPA 13R/13D for residential/limited applications) and the OBC referenced standards.

Standpipe systems are required in buildings over a certain height and in large-area buildings; they provide hose connections for firefighting.

Class I standpipes serve fire department use; Class II serve occupant use; Class III serve both.

Sprinkler systems must have a water supply adequate for the design density and duration; fire pumps are provided where pressure is insufficient.

Sprinkler control valves must be supervised and accessible; the main drain and flow test connections are required for testing.

Sprinklered buildings may be permitted increased travel distance, reduced fire separations, and larger unprotected openings.

Residential sprinkler systems (NFPA 13R) are permitted in residential occupancies up to a limited height and are designed for life safety rather than property protection.

Smoke control systems are required in high-rise buildings, in certain atria, and in buildings with large undivided floor areas.

Smoke control may use pressurization of exit stairs and corridors, exhaust of the fire floor, or a combination; the design must maintain tenability along egress paths.

Smoke venting is required in some occupancies (e.g. certain industrial and storage occupancies) to release hot gases and improve firefighting conditions.

Firefighter access provisions include firefighter elevators, standpipe connections, and a fire command centre in high-rise buildings.

A fire command centre must be located near the principal entrance and must contain fire alarm annunciation, smoke control controls, and communication equipment.

Smoke control systems must be commissioned and tested; the design must consider make-up air and pressure differentials across boundaries.

Venting of concealed spaces and attic spaces may be required to prevent accumulation of hot gases.

Fire department access routes, siamese connections, and hydrant locations must be provided and maintained clear.

Part 9 applies to small buildings (typically within height and area limits for Part 9); it contains simplified fire protection requirements.

Smoke alarms are required in dwelling units and must be installed on each storey and near sleeping areas; they may be hardwired and interconnected.

Fire separations between dwelling units and between dwelling units and common spaces must have an FRR (typically 45 min or as required).

Egress from dwelling units must provide an exit or an egress window; egress window dimensions and sill heights are specified.

Sprinkler requirements for Part 9 residential buildings are limited but may apply to certain occupancies or sizes.

Fire blocking and draft stopping are required in concealed spaces to limit fire spread in combustible construction.

Chimneys, flues, and venting must be installed with clearances to combustibles as specified.

Means of egress from a house must not pass through a garage or other hazardous area without protection.

Flammable liquids have a flash point below 37.8 °C; combustible liquids have a flash point at or above 37.8 °C; the OBC and NFC classify liquids by flash point and boiling point.

Storage and dispensing of flammable and combustible liquids are governed by the National Fire Code of Canada and referenced standards (e.g. ULC/ORD-C142).

Hazardous operations require separation from other occupancies by fire separations with an FRR and may require explosion venting.

Dust-producing operations and combustible dusts present explosion hazards; ignition sources must be controlled and equipment bonded and grounded.

Flammable liquid storage rooms and cabinets have limits on quantity and require fire-rated construction and ventilation.

Special fire risks include hazardous processes, spray booths, dip tanks, and areas with oxidizers; these require engineered protection.

Explosion venting must be designed to relieve pressure to a safe location and must not endanger occupants or adjacent buildings.

Emergency power and lighting are required where hazardous operations could impair egress during a fire or power failure.