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Home / Assemblies / UL C121
UL C1214-hr Fire RatingJoint System
Design

Wall-to-Wall Joint — Intumescent System

UL-listed 4-hour fire-rated wall-to-wall joint system. Wall-to-Wall Joint, 1" max width, Intumescent putty pad with ceramic fiber backer.

Cross-Section Diagram

12FIRE-RATED JOINTSECTION · NOT TO SCALE2 LAYERSsee legend for ① ② ③
Legend
1Ceramic fiber backer(3")
2Intumescent putty pad(3/8")

Specifications

Fire Rating
4-Hour
Load Bearing
No
Total Thickness
Varies
Source / Publisher
UL (Underwriters Laboratories)
Design Number
C121
Assembly Type
Joint System
Test Standard
ASTM E1966
Construction Group
N/A
Number of Layers
2 layers

Applicable Codes

IBC 2024 §714IBC 2021 §714

Construction Summary

Wall-to-Wall Joint, 1" max width, Intumescent putty pad with ceramic fiber backer

Material Layers

LayerMaterialThickness
1Ceramic fiber backer3"
2Intumescent putty pad3/8"

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.