3M™ Fire Barrier Cast-In Tub Box Assembly, 3TB, 3 in

Code-Compliant Slab Void Creation. Seamless Cast-In Device Fitment. High-Volume Construction Speed.

The 3M Cast-In Tub Box Assembly introduces ultimate layout efficiency, built-in fire safety, and substantial labor savings to high-density multi-family housing and commercial concrete structure pours. Purpose-built to optimize bathtubs and floor drain installations on suspended concrete decks, this specialized 3-inch deep tub box fastens straight onto a 2-inch 3M™ Fire Barrier Cast-In Device for Metallic Penetrations before the concrete truck arrives. It provides mechanical contractors, commercial plumbers, and concrete forming crews with an integrated, code-compliant path to form a precise, uniform void in the upper deck surface without risking structural cracking or requiring expensive, dusty aftermarket concrete coring lines.

Uncompromising fire containment ratings and simple field stripping are core components of this 3M 3TB design. The assembly features a high-density, 3-inch thick removable foam block core that holds its shape under the intense hydrostatic weight of fresh concrete, and pulls out cleanly once the slab is fully cured to establish an inspection-ready workspace for below-floor trap layouts. When paired with a matching 3M metallic cast-in anchor, this system easily handles concrete depths as thin as 4-1/2 inches, providing a robust thermal shield that expands under extreme fire exposure to choke off toxic smoke and flame transitions between vertical floor boundaries.

Why the 3M™ 3TB Cast-In Tub Box System Runs the Deck Layout:

• Precision Sub-Floor Void Engineering: Creates a clean, 3-inch deep recess directly on the surface of the cured slab, ensuring immediate access to tub traps and drain lines.
• Eliminates Expensive Diamond Coring: Forms plumbing pathways during the primary pour stage, saving thousands of dollars in coring labor and diamond bit wear.
• Authentic 3M™ Built-In Compatibility: Fastens securely onto standard 2-inch 3M Fire Barrier Cast-In Devices for metallic penetrations with an absolute mechanical fit.
• Adaptive Pipe Sizing Range: Accommodates a versatile range of drain line paths from 1-1/2 inch up to 2-inch nominal diameters for flexible field configuration.
• Flawless Foam Strip Profiles: Heavy-density foam block core stands up to tough mechanical vibration during concrete pours but pulls free quickly without sticking to the walls.

Suggested Applications:

• Used with 2-inch 3M Fire Barrier Cast-In Device for Metallic Pipes to firestop cPVC, PVC, ccABS and ABS pipes penetrating concrete floors with fire ratings up to 3 hours. It maybe applied to drain, waste and vent or closed pipe systems

Specifications