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Home / Assemblies / UL U321
UL U3211.5-hr Fire RatingWallSTC 59
Steel StudMulti-Layer GypsumFiberglass BattPartitionHigh STCDesign

Shaft Wall — 2 layers 1" Type C

UL-listed 1.5-hour fire-rated shaft wall assembly. 2-1/2" CT studs at 24" o.c. with R-11 fiberglass batt, 2 layers of 1" Shaftliner gypsum board each side.

Cross-Section Diagram

1234568.00"WALL ASSEMBLYSECTION · NOT TO SCALE6 LAYERSsee legend for ① ② ③
Legend
11" Shaftliner gypsum board(1")
21" Shaftliner gypsum board(1")
32-1/2" CT studs at 24" o.c.(2.5")
4R-11 fiberglass batt
51" Shaftliner gypsum board(1")
61" Shaftliner gypsum board(1")

Specifications

Fire Rating
1.5-Hour
STC Rating
STC 59
Load Bearing
No
Total Thickness
6.5"
Source / Publisher
UL (Underwriters Laboratories)
Design Number
U321
Assembly Type
Wall
Test Standard
UL 263
Construction Group
Concrete/Masonry
Number of Layers
6 layers

Applicable Codes

IBC 2021 Table 722.1IBC 2024 Table 722.1

Construction Summary

2-1/2" CT studs at 24" o.c. with R-11 fiberglass batt, 2 layers of 1" Shaftliner gypsum board each side

Material Layers

LayerMaterialThickness
11" Shaftliner gypsum board1"
21" Shaftliner gypsum board1"
32-1/2" CT studs at 24" o.c.2.5"
4R-11 fiberglass batt—
51" Shaftliner gypsum board1"
61" 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.