Evaluation Report Substantiates ASW Position Statement
In January 2019, the Gypsum Association released a position statement to clarify the criteria for the placement of utilities in the flanking walls on either side of a two-hour, steel H-stud gypsum shaftliner panel, area separation wall (ASW). The position statement, “Gypsum Area Separation Firewalls and Utility Placement,” was necessary due to confusion among builders and code officials over the performance requirements of both the shaftliner system and the flanking walls.
Code compliant fire separation of townhouses or apartments can be achieved in three ways:
1. Double walls (two 1-hour fire-resistance-rated wall assemblies).
2. A common wall (fire-resistance rated 1 or 2 hours, depending on sprinklers).
3. An “area separation wall” (ASW), a common wall variation, consisting of one central fire-rated wall with a flanking walls attached with breakaway clips on either side (2-hour fire resistance rated).
Per the International Building Code (IBC), party walls shall be constructed without openings. Per the International Residential Code (IRC), common walls shall be constructed without plumbing or mechanical equipment, ducts, or vents in the common wall because such penetrations compromise fire resistance ratings. However, the flanking walls used on either side of a gypsum shaftliner system can accommodate plumbing or mechanical equipment, ducts, or vents without affecting fire resistance because the functionality of the steel H-stud gypsum shaftliner panel portion of the assembly serves as the fire separation. The shaftliner ASW is not compromised by utilities or penetrations placed in the flanking walls. A recent engineering evaluation substantiates the Gypsum Association position on ASWs.