What is true about fire-rated common walls in townhomes?

Fire-rated common walls in townhomes are designed to prevent the spread of fire between units, providing critical safety measures for occupants. The key characteristic of a fire-rated wall is that it must maintain its integrity and provide a barrier against fire and smoke for a designated period of time.

The reason why it is important that these walls cannot have any mechanical equipment installed is that any penetrations or alterations could compromise the fire-resistive integrity of the wall. Mechanical equipment can create openings in the wall assembly, which could allow fire and smoke to pass through, thus defeating the purpose of having a fire-rated separation. Building codes require that these common walls remain clear of any equipment to maintain their protective function.

This is why the assertion that fire-rated common walls cannot have any mechanical equipment is accurate and aligns with fire safety standards that prioritize the protection of life and property in multifamily housing arrangements. The other options do not accurately reflect building code requirements regarding fire-rated walls.