Which of these scenarios would most likely necessitate the use of firestop products?

The scenario involving renovation that creates openings between fire-rated walls is the most likely to require firestop products. Firestop products are specifically designed to restore the fire-resistance rating of a wall or floor assembly when penetrations or openings are made. When renovations are done that involve such openings, maintaining the integrity of the fire-rated construction is crucial to prevent the spread of fire and smoke between compartments in a building. Firestop measures ensure that any gaps or openings are sealed appropriately, thus preserving the safety features intended in fire-rated assemblies.

Other scenarios, such as the installation of new furniture, electrical upgrades, or routine maintenance checks, typically do not involve breaking through fire-rated barriers or creating penetrations that would compromise fire safety. Furniture installation and maintenance generally occur within the existing structures without affecting fire-rated assemblies, while electrical upgrades may involve wiring that uses existing pathways, thus posing less risk to fire-rated walls and floors.