3M™ intumescent caulks expand up to three times their original size when exposed to temperatures over 300°F (149°C). This intumescent action forms a strong, insulating char which seals the opening for up to four hours when exposed to extreme heat. Fire barrier caulks are ideal for new construction or retrofit in a wide variety of applications such as metal, plastic, insulated and glass pipe, construction gaps, dynamic joints, HVAC ductwork and insulated cable applications. Fire barrier caulks are all one-part systems requiring no mixing or measuring, and are fast drying, becoming tack-free in less than 30 minutes. All come in convenient job-size packages and install easily with a standard caulking gun, pneumatic pumping equipment or putty knife.
