Which incidental use spaces require a one-hour separation?

The correct answer pertains to the requirement for a one-hour separation between incidental use spaces, specifically involving spaces that contain operational equipment that poses fire hazards. In this case, the chiller room, when combined with a 30 HP boiler room, necessitates a one-hour separation due to the potential for high heat output and combustible materials.

High-pressure systems and heating equipment, like a boiler, can significantly increase fire risks, which is why building codes often call for these areas to be isolated from other less hazardous spaces. The one-hour separation provides an important safety measure to contain any potential fire or heat exposure, thereby protecting other parts of the building and maintaining safety for occupants.

This requirement is critical in maintaining code compliance and ensuring fire safety in architectural design, especially in mixed-use buildings where different types of operations and occupancy levels are present.