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Home / Assemblies / UL U191
UL U1914-hr Fire RatingWallLoad-BearingSTC 47
Wood StudMulti-Layer GypsumMineral WoolLoad-Bearing WallDesign

Wood Stud Wall — 3 layers 1/2" Type X

UL-listed 4-hour fire-rated wood stud wall assembly. 2x6 wood studs at 24" o.c. with R-15 mineral wool batt, 3 layers of 1/2" Type X gypsum board each side.

Cross-Section Diagram

1234567810.00"WALL ASSEMBLYSECTION · NOT TO SCALE8 LAYERSsee legend for ① ② ③
Legend
11/2" Type X gypsum board(1/2")
21/2" Type X gypsum board(1/2")
31/2" Type X gypsum board(1/2")
42x6 wood studs at 24" o.c.(5.5")
5R-15 mineral wool batt
61/2" Type X gypsum board(1/2")
71/2" Type X gypsum board(1/2")
81/2" Type X gypsum board(1/2")

Specifications

Fire Rating
4-Hour
STC Rating
STC 47
Load Bearing
Yes
Total Thickness
8.5"
Source / Publisher
UL (Underwriters Laboratories)
Design Number
U191
Assembly Type
Wall
Test Standard
ASTM E119
Construction Group
Light Frame
Number of Layers
8 layers

Applicable Codes

IBC 2021 Table 722.1IRC R302.1IBC 2024 Table 722.1

Construction Summary

2x6 wood studs at 24" o.c. with R-15 mineral wool batt, 3 layers of 1/2" Type X gypsum board each side

Material Layers

LayerMaterialThickness
11/2" Type X gypsum board1/2"
21/2" Type X gypsum board1/2"
31/2" Type X gypsum board1/2"
42x6 wood studs at 24" o.c.5.5"
5R-15 mineral wool batt—
61/2" Type X gypsum board1/2"
71/2" Type X gypsum board1/2"
81/2" Type X gypsum board1/2"

Important Notice

This assembly listing is for reference only. Always verify against the current UL Product iQ database before specifying in construction documents. Material substitutions may void the fire rating. Consult with a qualified fire protection engineer for project-specific requirements.