The required minimum fire flow is 500 gallons per minute , making option C correct.

2021 IFC Section 3313.1 requires an approved temporary or permanent water supply for fire protection to become available at specified stages of construction, including when combustible building materials arrive on the site. Section 3313.2 then establishes the specific requirement: when combustible building materials for the building under construction are delivered, a minimum fire flow of 500 gpm must be provided.

The hydrant supplying this flow must be located within 500 feet of the combustible building materials as measured along an approved fire apparatus access lane. If a single hydrant cannot provide the required coverage because of site configuration, additional hydrants are required.

The 500-gpm value in this question is the construction-stage minimum associated with combustible-material delivery. It should not be mistaken for the final required fire flow of the completed building. Depending on construction type, fire separation distance, building area, and subsequent phases of vertical construction, the required available water supply can be greater.

For mass timber projects, verifying this water supply before large timber packages arrive is a critical construction-phase fire-safety control.

References/Topics: 2021 IFC Sections 3313.1 and 3313.2; combustible building materials; minimum construction fire flow.

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