B
HomeLibrariesCopilotSearchProjectsBookmarks
FeedbackHelp Desk
Libraries
Building Codes
Code LibraryIBC — BuildingIRC — ResidentialIFC — FireIPC — PlumbingIMC — MechanicalIFGC — Fuel GasIECC — EnergyNEC — ElectricalModel Codes
Specifications
CSI SpecificationsDOT SpecsTransit SpecsUSACE
Standards
TransportationRailroadFire SafetyAccessibilityStructural
Tools & References
DiagramsAssembliesProductsCalculatorsChecklistsPermits
PricingLog in
Home / Assemblies / UL C120
UL C1203-hr Fire RatingJoint System
Mineral WoolDesign

Wall-to-Wall Joint — Intumescent System

UL-listed 3-hour fire-rated wall-to-wall joint system. Wall-to-Wall Joint, 2" max width, Intumescent sealant with mineral wool backer.

Cross-Section Diagram

12FIRE-RATED JOINTSECTION · NOT TO SCALE2 LAYERSsee legend for ① ② ③
Legend
1Mineral wool backer(1")
2Intumescent sealant(3/8")

Specifications

Fire Rating
3-Hour
Load Bearing
No
Total Thickness
Varies
Source / Publisher
UL (Underwriters Laboratories)
Design Number
C120
Assembly Type
Joint System
Test Standard
ASTM E814
Construction Group
N/A
Number of Layers
2 layers

Applicable Codes

IBC 2021 §714NFPA 5000

Construction Summary

Wall-to-Wall Joint, 2" max width, Intumescent sealant with mineral wool backer

Material Layers

LayerMaterialThickness
1Mineral wool backer1"
2Intumescent sealant3/8"

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.