Which characteristic is required for the installation of draft-blocking materials?

For the installation of draft-blocking materials, one critical characteristic is that they must be fire-resistant. This is essential because draft-blocking materials are often used in locations within a building where fire safety is a concern, such as around chimneys, ducts, and electrical penetrations. Fire-resistant materials help prevent the spread of fire and protect the building’s occupants and structural integrity.

Using non-fire-resistant materials could pose significant safety risks, as they might ignite and contribute to the spread of flames and smoke in the event of a fire. Thus, ensuring that draft-blocking materials can withstand high temperatures and resist combustion is crucial for compliance with fire codes and enhancing the building's overall safety.

While other factors, such as allowing for air passage, ease of removal, and insulation against temperature, are important in building insulation and draft control, they do not carry the same critical safety implications as fire resistance, which is paramount for draft-blocking materials.