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Home / Assemblies / UL U331
UL U3314-hr Fire RatingWallSTC 55
Steel StudMulti-Layer GypsumMineral WoolPartitionHigh STCDesign

Shaft Wall — 4 layers 1" Type C

UL-listed 4-hour fire-rated shaft wall assembly. 2-1/2" CT studs at 24" o.c. with R-8 mineral wool, 4 layers of 1" Shaftliner gypsum board each side.

Cross-Section Diagram

1234567891012.00"WALL ASSEMBLYSECTION · NOT TO SCALE10 LAYERSsee legend for ① ② ③
Legend
11" Shaftliner gypsum board(1")
21" Shaftliner gypsum board(1")
31" Shaftliner gypsum board(1")
41" Shaftliner gypsum board(1")
52-1/2" CT studs at 24" o.c.(2.5")
6R-8 mineral wool
71" Shaftliner gypsum board(1")
81" Shaftliner gypsum board(1")
91" Shaftliner gypsum board(1")
101" Shaftliner gypsum board(1")

Specifications

Fire Rating
4-Hour
STC Rating
STC 55
Load Bearing
No
Total Thickness
10.5"
Source / Publisher
UL (Underwriters Laboratories)
Design Number
U331
Assembly Type
Wall
Test Standard
UL 263
Construction Group
Concrete/Masonry
Number of Layers
10 layers

Applicable Codes

IBC 2021 §722IBC 2024 §722NFPA 5000

Construction Summary

2-1/2" CT studs at 24" o.c. with R-8 mineral wool, 4 layers of 1" Shaftliner gypsum board each side

Material Layers

LayerMaterialThickness
11" Shaftliner gypsum board1"
21" Shaftliner gypsum board1"
31" Shaftliner gypsum board1"
41" Shaftliner gypsum board1"
52-1/2" CT studs at 24" o.c.2.5"
6R-8 mineral wool—
71" Shaftliner gypsum board1"
81" Shaftliner gypsum board1"
91" Shaftliner gypsum board1"
101" Shaftliner gypsum board1"

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.