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Home / Assemblies / UL D114
UL D1143-hr Fire RatingFloor/CeilingLoad-BearingSTC 55
Steel JoistFiberglass BattHigh STCDesign

Steel Joist Floor/Ceiling — 2 layers Spray-applied fireproofing

UL-listed 3-hour fire-rated steel joist floor/ceiling assembly. Open-web steel joists at 24" o.c. with R-19 fiberglass batt, 2 layers of Spray-applied fireproofing ceiling.

Cross-Section Diagram

123456FLOOR/CEILING ASSEMBLYSECTION · NOT TO SCALE6 LAYERSsee legend for ① ② ③
Legend
1Floor covering(varies)
23" concrete on steel deck(3")
3Open-web steel joists at 24" o.c.(14.0")
4R-19 fiberglass batt
5Spray-applied fireproofing(1-1/2")
6Spray-applied fireproofing(1-1/2")

Specifications

Fire Rating
3-Hour
STC Rating
STC 55
Load Bearing
Yes
Total Thickness
18.5"
Source / Publisher
UL (Underwriters Laboratories)
Design Number
D114
Assembly Type
Floor/Ceiling
Test Standard
ASTM E119
Construction Group
Non-Combustible
Number of Layers
6 layers

Applicable Codes

IBC 2021 Table 722.1IBC 2024 Table 722.1

Construction Summary

Open-web steel joists at 24" o.c. with R-19 fiberglass batt, 2 layers of Spray-applied fireproofing ceiling

Material Layers

LayerMaterialThickness
1Floor coveringvaries
23" concrete on steel deck3"
3Open-web steel joists at 24" o.c.14.0"
4R-19 fiberglass batt—
5Spray-applied fireproofing1-1/2"
6Spray-applied fireproofing1-1/2"

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.