UL Design HW-D-0034

2-Hour Fire Rated Head-of-Wall Joint — HW-D-0034

UL System HW-D-0034 (category XHBN) — Head-of-wall joint at the top of a 1- or 2-hr gypsum board/steel stud wall (U400 or V400 series design) meeting the underside of a fire-rated fluted steel deck with min 2-1/2" concrete topping (or min 4-1/2" concrete slab / 6" hollow-core precast alternate). A nominal 1" gap is left between the top of the gypsum board and the deck. Flutes above the wall are packed with 4 pcf mineral wool cut to the flute shape and compressed (min 4-1/4" depth for 1 hr, 5-5/8" for 2 hr), with additional 2"-thick wool strips compressed 50% into the 1" linear gap. A min 1/4" thickness of SpecSeal ES or LC150 sealant is applied on each side of the wall over the wool, flush with the wall surfaces. An optional deflection channel may be used. Nominal joint width up to 1"; movement capability 25% compression or extension (SpecSeal ES); 7% with SpecSeal LC150.