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IBC Chapter 8 — Interior Finishes

Updated Mar 25, 2026

Flame spread and smoke-developed requirements for interior wall/ceiling finishes and floor finishes based on occupancy and location within the building.

Section 803: Wall and ceiling finishes — classified by ASTM E84 flame spread index. Class A: 0-25 FSI, 0-450 SDI. Class B: 26-75 FSI, 0-450 SDI. Class C: 76-200 FSI, 0-450 SDI. Exit enclosures and passageways: Class A. Corridors: Class A or B. Rooms/areas: Class A, B, or C depending on occupancy. Sprinklers allow one class reduction. Section 804: Interior floor finish — critical radiant flux test (ASTM E648). Class I: min 0.45 W/cm². Class II: min 0.22 W/cm². Exit enclosures: Class I. Corridors: Class I (I-2, I-3) or Class II. Section 806: Decorations and trim — flame-resistant in A, E, I occupancies. Foam plastics not permitted as interior finish unless covered by thermal barrier (Section 2603).

TAGS

IBC interior-finish flame-spread smoke-developed floor-finish

DETAILS

classes

{"A":"0-25 FSI","B":"26-75 FSI","C":"76-200 FSI"}

code year

2024

code system

IBC

code section

Chapter 8

RELATED KNOWLEDGE

IBC 903.2.1 — Group A Occupancies (Sprinkler Requirements)

Automatic sprinkler system required throughout buildings with Group A occupancy where fire area exceeds 5,000 square feet, or overall building area exceeds 12,000 square feet, or occupant load of the fire area exceeds 300.

IBC 903.2.7 — Group M Occupancies (Retail Sprinkler Requirements)

Automatic sprinkler system required in Group M (mercantile) occupancies where fire area exceeds 12,000 square feet or building is more than three stories above grade.

IBC 903.2.11.3 — Buildings 55 Feet or More in Height

Automatic sprinkler system required throughout buildings with a floor level having an occupant load of 30 or more that is located 55 feet or more above the lowest level of fire department vehicle access.

IBC 1015.1 — Exit and Exit Access Doorways Required

Two exits or exit access doorways required from any space where occupant load exceeds the table values. Spaces with occupant load exceeding 500 require a minimum of 3 exits. Spaces exceeding 1,000 require 4 exits.

IBC 1017.2 — Exit Access Travel Distance

Maximum travel distance from any point in a building to an exit shall not exceed 200 feet unsprinklered or 250 feet sprinklered for most occupancies. Specific occupancies have modified limits.

IBC Table 601 — Fire-Resistance Rating Requirements

Specifies minimum fire-resistance ratings for structural elements based on construction type (Type I through V). Type IA requires 3-hour rated structural frame, 2-hour floors, and 1.5-hour roof.

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