ICC BCS cheat sheet

Code hierarchy: model code (IBC) → adopted local amendments → referenced standards (ASTM, NFPA, ASCE 7); the most restrictive applicable provision governs where documents conflict.

Occupancy classification drives nearly every other decision: egress width, fire separation, sprinkler thresholds, and height/area limits are all indexed to occupancy group.

Type of construction (I–V) with A/B subtypes sets allowable height and area; Type IA/IB use noncombustible protected construction, Type VB is the least restrictive.

Allowable area formula: Aa = At × If (frontage increase) × Is (sprinkler increase); tabular area At comes from the occupancy/construction table.

Height in stories is limited separately from height in feet; a building may satisfy one limit and exceed the other, so both must be checked.

Mixed occupancy: either apply the most restrictive requirements to the whole building or use the separated-occupancy method with fire barriers sized to the occupancy hazard.

Means of egress is a continuous path: exit access → exit → exit discharge; each segment has its own width, travel distance, and enclosure rules.

Fire-resistance ratings are stated in hours and tested per ASTM E119; opening protectives (doors, windows) require ratings proportional to the wall rating.

Egress width: capacity is calculated per occupant from the occupant load factor for the use; stairways and other egress components have different capacity factors.

Travel distance is measured along the natural path of travel to the nearest exit; sprinklered buildings typically receive an increase (commonly 250 ft vs 200 ft unsprinklered for many occupancies).

Common path of egress travel and dead-end limits are separate checks from total travel distance and frequently control small tenant spaces.

Two exits are generally required once occupant load exceeds the threshold for the occupancy; remoteness of exits requires separation of at least half the diagonal.

Accessible routes must connect to public ways; ramps, door clear widths, and reach ranges follow ICC A117.1 dimensional criteria.

Alterations trigger upgrade requirements: the work area compliance method scales required upgrades to the scope, while the prescriptive method applies fixed improvements.

Change of occupancy is evaluated against the code's occupancy classification tables; a more hazardous classification can require new separations and egress.

Inspections and certificates of occupancy are procedural gates: foundation, framing, and final inspections must pass before occupancy is lawful.