A fact finding study at a nationally recognized private testing laboratory established that the fire-resistance rating of a typical wall having a one- hr fire--resistance rating is compromised when openings are provided for the penetration of duct systems.

This study confirmed that the presence of fire dampers significantly reduced heat transfer to the unexposed side of -the wall.

There is no protocol to assess the potential hazards of eliminating the requirement for an opening protective device in a one-hour rated wall or partition.

In the absence of protocol, codes and standards should not permit (by exception) the elimination of fire dampers in walls or partitions required to have a one-hour fire-resistance rating and opening protective rating of 20 minutes or more.

Units: Dual