Fire & Acoustic Seals Fire Rated Intumescent and Acoustic Acrylic Sealant is a halogen free, polymer emulsion based sealant that swells when subjected to temperatures in excess of 125?C and forms a char coat that restricts the passage of smoke and fire. It is easily applied and dries to a flexible and smooth surfaced material which is readily over paintable. It has excellent adhesion to a wide range of substrates and will not harden or crack with age.