OBC Large Buildings flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Building height definition

The vertical distance measured from grade to the highest finished floor level of the top storey, excluding rooftop mechanical penthouses and similar projections that do not constitute storeys.

Building area definition

The greatest horizontal area of the building above grade, measured within the exterior faces of exterior walls and projected over the entire building footprint.

Occupant load calculation

The number of persons a space is designed to hold, found by dividing floor area by the occupant-load factor for the use, or by counting fixed seats.

Exit versus exit access

An exit is a protected continuous path from the floor area to a public way. Exit access is the unprotected portion leading from the occupied space to the exit.

Firewall versus fire separation

A firewall divides a building into two separate buildings for code purposes. A fire separation divides portions of one building and does not create separate buildings.

Spatial separation measurement

The distance from the building face to the lot line or exposing building face, used to limit unprotected openings and to set the required fire-resistance rating of exterior walls.

Sprinkler height and area allowances

Automatic sprinkler protection permits increased building height and area and reduced fire-resistance ratings, within the specific limits the code sets for each occupancy and construction type.

Limit-states design principle

Design must satisfy ultimate limit states, where factored resistance exceeds factored load effects, and serviceability limit states, which control deflection, vibration, and cracking under normal use.

Load combination purpose

Load combinations apply specified factors to dead, live, snow, wind, and earthquake effects so that the structure is checked for realistic worst-case concurrent loading.

Snow drift load

An additional snow load imposed where a roof step, parapet, or adjacent taller building traps snow, calculated from the upwind fetch and the height difference.

Air barrier continuity

The air barrier must form a continuous sealed plane across the envelope, including joints, penetrations, and interfaces, to control air leakage and moisture transport.

Vapour barrier placement

In cold climates the vapour barrier is placed on the warm side of the insulation, and its need and position depend on a moisture analysis of the assembly.

Rain screen principle

Envelope design controls rain by deflection at the outer surface, drainage in a cavity behind the cladding, and drying of any moisture that penetrates.

Effective thermal resistance

The thermal resistance of an assembly accounting for thermal bridging at framing, structural penetrations, and junctions, rather than the nominal insulation value alone.

Lighting power density

The maximum permitted lighting wattage per unit of floor area for a space type, used to limit energy use and often paired with automatic control requirements.

Apparent sound transmission class

A field-measured rating of airborne sound insulation between spaces, including flanking paths, used to set minimum separation performance between dwelling units.

Demand control ventilation

A control strategy that modulates outdoor air supply in response to measured occupancy, such as carbon dioxide concentration, to reduce energy use while maintaining indoor air quality.

Assembly occupancy

An occupancy for gatherings of people for amusement, recreation, social, religious, or similar purposes, subdivided by occupant load and by fixed or non-fixed seating.

Institutional occupancy

An occupancy where occupants are cared for or detained, subdivided by whether occupants can escape without assistance, which controls sprinkler and egress requirements.

Mixed occupancy treatment

Multiple uses in one building are either separated by fire separations and treated as distinct occupancies, or treated as one occupancy with the most restrictive requirements applied.

Construction type limits

Each construction type, from noncombustible to combustible, carries permitted maximum building heights and areas for each occupancy group, modified by sprinkler protection.

Mezzanine area limit

A mezzanine is limited in area relative to the storey below and must be open to that storey, or it is treated as a separate storey with full egress and separation.

Travel distance to exit

The length of the egress path measured along the route of travel from the most remote point in a space to the nearest exit, limited by occupancy and sprinkler status.

Two means of egress

Two separate exits are required where occupant load, travel distance, or common-path limits are exceeded, and the exits must be separated by the required distance.

Accessible route requirement

A continuous unobstructed path from the public way to the building entrance and to all normally occupied spaces, accessible washrooms, parking, and services.

Guard height and openings

Guards are required where the level difference exceeds the code threshold, with a specified minimum height and limits on openings that could permit passage of a sphere.

High building measures

Buildings above the code height threshold require additional life safety measures, including smoke control, stair pressurization, emergency power, and voice communication.

Alternative solution requirement

A proposed substitute for an acceptable solution must demonstrate equivalent performance and address every relevant objective and functional statement, supported by analysis or testing.

Atrium smoke control

Interconnected floor spaces and atria require smoke control analysis and systems demonstrating that smoke will not compromise egress from any occupied level.

Building permit requirement

A permit is required before construction, alteration, or change of use, supported by drawings and specifications sufficient to demonstrate compliance with the code.

Field review purpose

A designer's field review confirms that construction conforms to the sealed drawings and specifications, with deficiencies reported and resolved before occupancy.

Occupancy authorization

Authorization to occupy is issued after inspection confirms that required life safety systems are operational and that the building complies with the permitted documents.