UL Design U373
2-Hour Fire Rated Area Separation Wall — 2" shaftliner panel in H-studs
UL Design U373 — 2-hour area separation (party) wall for townhouse construction. Two layers of 1" x 24" gypsum shaftliner panels friction-fit into 2" steel H-studs (25 ga) at 24" o.c., C-runners top and bottom, held with a minimum 3/4" air space to the adjacent wood framing on each side and attached with aluminum breakaway clips at each floor line so a burning unit can collapse without pulling the wall down. Insulated flanking walls raise STC into the 60s per manufacturer literature.
2 x 1" gypsum shaftliner in 2" H-studs @ 24" o.c., 3/4" air space to framing each side, breakaway clips
The full text is for BuildSpec members
Read the complete section, search across every adopted code, run the calculators and ask Copilot — free for 14 days, no card required.
- Layer-by-layer components with thicknesses
- Cross-section diagram
- Applicable code sections and test standard
- 6 related assemblies