4.1general provisions

The methods contained in this appendix provide regulatory evidence of compliance in accordance with the design applications outlined in this section.

4.1.1 Performance Objective

Structural components, members, and building frame systems shall be designed so as to maintain their load-bearing function during the design-basis fire and to satisfy other performance requirements specified for the building occupancy.

Deformation criteria shall be applied where the means of providing structural fire resistance, or the design criteria for fire barriers, requires evaluation of the deformation of the load-carrying structure.

Within the compartment of fire origin, forces and deformations from the design-basis fire shall not cause a breach of horizontal or vertical compartmentation.

4.1.2 Design by Engineering Analysis

The analysis methods in Section 4.2 are permitted to be used to document the anticipated performance of steel framing when subjected to design-basis fire scenarios. Methods in Section 4.2 provide evidence of compliance with performance objectives established in Section 4.1.1.

The analysis methods in Section 4.2 are permitted to be used to demonstrate an equivalency for an alternative material or method, as permitted by the applicable building code (ABC).

Structural design for fire conditions using Appendix 4.2 shall be performed using the load and resistance factor design (LRFD) method in accordance with the provisions of Section B3.1, unless a design based on advanced analysis is performed in accordance with Section 4.2.4c. Ambient resistance factors shall be used with the LRFD method.

4.1.3 Design by Qualification Testing

The qualification testing methods in Section 4.3 are permitted to be used to document the fire resistance of steel framing subject to the standardized fire testing protocols required by the ABC.

4.1.4 Load Combinations and Required Strength

In the absence of ABC provisions for design under fire exposures, the required strength of the structure and its elements shall be determined from the gravity load combination as follows:

(A-4-1)

where

$\begin{aligned} A_{T} & =\text { nominal forces and deformations due to the design-basis fire defined in } \\ & \text { Section 4.2.1 }\end{aligned}$

$D=$ nominal dead load

• $L \quad=$ nominal occupancy live load
• $S=$ nominal snow load

User Note: ASCE/SEI 7, Section 2.5, contains Equation A-4-1 for extraordinary events, which includes fire. Live load reduction is usually considered in accordance with ASCE/SEI 7.