Acrylic Firestop Joint Spray

Elastomeric firestop joint sprays are used as passive fire protection to prevent the spread of water, flames, smoke, and hot gasses through joint openings in horizontal and vertical surfaces, and are sprayed over other firestopping backing materials. Elastomeric firestop joint sprays are based on a variety of chemistries including silicone, acrylic, or hybrid technologies that incorporate polyurethanes or modified polyethers. This Common Product describes a red acrylic firestop joint spray that can be used on general construction joints, curtain wall joints, and through penetrations. These products cure through the evaporation of water, and generally take one to several days to fully cure. The dried firestop material remains elastomeric to accommodate use in both static and dynamic joints. Generally, mineral wool is packed into the gaps and the spray coating is applied at 1/8" wet thickness over the insulation and adjacent substrates. Similar to other types of water-based adhesives and sealants, acrylic firestop joint sprays require antimicrobial preservatives and product literature indicates that they are present. These preservatives are not well disclosed. In the past, chlorothalonil (CASRN 1897-45-6), a known carcinogen, was common. It is also known to be present in other types of acrylic firestopping products, but the research conducted for this Common Product was unable to confirm its presence in current spray-applied product formulations. Other preservatives identified were below the common content disclosure threshold (100 ppm), and are included in the All Contents tab for reference. While not identified as common these products can contain orthophthalates, a class of chemicals of concern due to their endocrine disrupting properties and other hazards.

A historical version of this CP is available here: https://pharos.habitablefuture.org/common-products/2223191