Rectorseal 66616 Firestop Sealant 10.3 Oz Intumescent Caulk

Product Description

The RECTORSEAL 66616 is a single-component, water-based intumescent firestop sealant designed to prevent the spread of fire, smoke, hot gases, and water through construction joints and penetrations in fire-rated walls and floors. Rated for 1-, 2-, and 3-hour fire assemblies and tested to ASTM E814 (UL 1479), UL 2079, and ULC-S115-95 standards, this sealant cures to a flexible elastomeric seal capable of handling dynamic movement. It carries an STC rating of 53 and is VOC compliant. HVAC, plumbing, and construction trades rely on it for both new construction and retrofit firestopping applications.

The 66616 is formulated for interior use in fire-rated wall and floor assemblies where penetrations and joints require a code-compliant firestop. It suits new-construction rough-in work as well as retrofit situations where existing penetrations need to be brought into compliance. The sealant is paintable and offers strong freeze-thaw stability, making it practical across a range of jobsite conditions. No pre-mixing is required, and no specialized application skills are needed beyond standard caulking technique.

Key Features

• Rated for 1-, 2-, and 3-hour fire assemblies per ASTM E814 (UL 1479), UL 2079, and ULC-S115-95
• Highly intumescent, water-based formula blocks fire, smoke, hot gases, and water infiltration
• Non-sag caulking grade - suitable for vertical and overhead joint applications
• Cures to an elastomeric seal that accommodates dynamic joint movement
• Applicable from tube, sausage pack, or pail using a standard caulking gun, bulk loading gun, or trowel
• Paintable, VOC compliant, and rated for interior use up to 120 degrees F with excellent freeze-thaw performance

Compatibility

Designed as an OEM-style firestop solution for construction joints and penetrations in fire-rated wall and floor assemblies. Suitable for use in residential and commercial construction projects requiring code-compliant firestopping at pipe, conduit, duct, and structural joint locations.

Installation Notes

Installation should be performed by a licensed contractor or qualified tradesperson familiar with applicable fire and building codes, including IBC and local authority having jurisdiction (AHJ) requirements. Surfaces must be clean, dry, and free of oil or loose material before application. Apply at joint or penetration openings using a standard caulking gun or bulk loading gun, tooling to the required depth per the tested assembly. Do not use this product as a substitute for a tested firestop system where a specific listed assembly is required by code.