Building Codes, Occupant Load, and Means of Egress

Vocabulary flashcards covering building code origins, model code systems, occupant load calculations, and means of egress requirements from Lectures 5, 7, 8, and 9.

Code of Hammurabi (1772 BCE)

An early building law stating that if a builder constructs a house poorly and it collapses and kills the owner, the builder shall be put to death.

Building Code

Regulations covering overall building and interior requirements, including occupancy, construction, egress, accessibility, and building systems, which are updated on a $3\text{-year}$ publication cycle.

Fire Code

Regulations addressing fire hazards, fire protection systems, hazardous materials, operations, and emergency preparedness.

Life Safety Code

A code (such as NFPA 101) concentrating on occupant safety, protection from fire, smoke, and toxic fumes, and safe evacuation in both new and existing buildings.

International Code Council (ICC)

An organization formed in 1994 by BOCA, ICBO, and SBCCI to develop a single set of comprehensive national model construction codes, known as the I-Codes.

Authority Having Jurisdiction (AHJ)

The entity or code official (including plans examiners, fire marshals, and building inspectors) responsible for enforcing, administering, interpreting, and approving compliance with adopted codes.

Model Code

A code published by an organization like ICC or NFPA that does not automatically become law until officially adopted by a state, county, or city jurisdiction.

Prescriptive Code

A code requirement that specifies exact dimensions, materials, or construction conditions ('do this') to achieve compliance.

Performance Code

A code requirement that specifies a desired outcome or performance level ('achieve this outcome') rather than specific construction methods, allowing alternative design solutions with official approval.

Standards

Technical specifications and test methods (developed by organizations such as ASTM, ANSI, ASHRAE, or NFPA) that have no legal standing on their own unless referenced by an adopted building code.

Occupational Safety and Health Administration (OSHA)

A federal agency established in 1970 that sets and enforces standards for safe and healthy working conditions, directly regulating construction safety and employer workplace design.

Means of Egress

A continuous and unobstructed path of vertical and horizontal circulation from any occupied point in a building to a public way.

Evacuation

An egress strategy in which occupants completely leave a building during an emergency.

Defend in Place

An egress strategy in which occupants remain in or move to a designated protected location inside a building when immediate evacuation is difficult or unsafe.

Exit Access

The portion of a means of egress that leads from any occupied point in a building to an exit, including rooms, doorways, corridors, aisles, and ramps.

Exit

The protected portion of a means of egress separated from other building spaces by fire-resistance-rated construction, such as exterior exit doors, enclosed exit stairs, horizontal exits, and exit passageways.

Exit Discharge

The portion of a means of egress between the termination of an exit and a public way, which may include lobbies, discharge corridors, egress courts, yards, or alleys.

Public Way

A street, alley, or open parcel of land deeded or dedicated for public use, having a clear width and height of not less than $10\,\text{feet}$.

Horizontal Exit

A protected egress route leading through a fire-resistance-rated wall and door assembly to a refuge area on the same floor level.

Area of Refuge

A temporary, protected location inside a building where occupants who cannot use stairs can wait safely for assistance or evacuation.

Exit Passageway

An enclosed, fire-rated horizontal route that extends an exit stair enclosure to an exterior exit door.

Handrail

A rail designed for guidance and support on stairs or ramps, required at a height between $34\,\text{inches}$ and $38\,\text{inches}$ above the walking surface.

Guard (Guardrail)

A building component located near open sides of elevated walking surfaces higher than $30\,\text{inches}$ above the floor, designed to prevent falls and requiring a minimum height of $42\,\text{inches}$.

Half-Diagonal Rule

The exit remoteness requirement stating that two required exits must be separated by a distance not less than half the length of the maximum overall diagonal dimension of the space served (reduced to one-third in sprinklered buildings).

Common Path of Travel

The portion of an exit access route that occupants must traverse before two separate and distinct paths of travel to separate exits become available.

Exit Access Travel Distance

The distance measured along the natural, unobstructed path of travel from the most remote occupiable point in a space to the entrance of an exit.

Dead-End Corridor

A corridor or hallway that provides exit access in only one direction, forcing occupants to retrace their steps if blocked by fire or smoke.

Occupancy Classification

The code-assigned category given to a building or space based on its general usage type (e.g., Group B Business, Group M Mercantile, Group A Assembly).

Function of Space

The specific activity occurring within a room or area, used to select the appropriate occupant load factor from code tables.

Occupant Load (OL)

The calculated total number of persons who can safely occupy a space or floor at one time, calculated as $\text{OL} = \text{Floor Area} \div \text{Occupant Load Factor}$.

Occupant Load Factor (OLF)

The floor area allowance per occupant (expressed in gross or net square feet per person) specified in code tables for a given function of space.

Gross Floor Area

The area within the inside perimeter of the exterior walls of a building, including interior walls, corridors, restrooms, storage, and service spaces.

Net Floor Area

The actual usable floor space occupied by a specific function, excluding interior walls, circulation corridors, restrooms, mechanical, and support spaces.

Linear Bench Seating Calculation

The occupant load calculation method for fixed bench seating without dividing arms, based on one person for every $18\,\text{inches}$ ($457\,\text{mm}$) of seating length measured at the front edge.

Booth Seating Calculation

The occupant load calculation method for seating booths, based on one person for every $24\,\text{inches}$ ($610\,\text{mm}$) of booth seat length measured at the backrest.

Primary and Secondary Spaces

An egress arrangement where occupants pass through an intervening secondary space from a primary space to reach an exit, allowed only if the spaces are related, non-hazardous, unlocked, and non-storage areas.