Spray foam insulation (SPF) is a site-applied foam insulation for residential, commercial, and industrial applications. It can be used in various applications including interior or exterior walls, attics, ceilings, and crawls spaces. SPF is a two-part polyurethane based foam comprised of a isocyanate part (the A side) and a polyol part (the B side) that are combined and reacted on site as applied. The B side of SPF also contains blowing agents, flame retardants, catalysts, and surfactants. SPF can be either open or closed cell and both can be used to create a continuous air barrier, depending on the thickness of foam that is applied. Open and closed cell spray foam insulation are similar in composition, but open cell foams use water as the sole blowing agent and contain a larger weight percentage of flame retardant, around 25% of the B side. They also may contain nonylphenol ethoxylate emulsifiers or use different polyols. Closed cell foams typically use fluorocarbon blowing agents, including hydrofluorocarbons (HFCs) with a high global warming potential (GWP), or hydroluoroolefins (HFOs) which are newer low global warming potential alternatives. While HFOs do not themselves have high GWP, they do use high GWP and/or ozone depleting substances in the manufacturing process. U.S. EPA regulations that would have prohibited the use of HFCs in SPF insulation by 2020 were partially overturned in Federal court rulings, so manufacturers already using HFCs are allowed to continue using them. Several U.S. states have moved forward with their own bans on HFCs in SPF, many of which have gone into effect (Theodoridi, 2020). Most spray foam insulation manufacturers continue to offer their HFC versions of SPF, even as they have introduced an HFO version. This CP covers a medium density (~2 lb/ft3) spray foam insulation with an HFC blowing agent. Formulations that instead use HFOs appear to be similiar. 

Since SPF products are reacted and applied on site, special care must be taken to avoid occupational exposure to the isocyanates, amines, flame retardants, etc. during the application process. Many SPF applicators undergo training and professional certification. Personal protective equipement usually includes full body protection in the form of disposable coveralls, chemical-resistant gloves and boots or booties, a hood, and eye and face protection as well as supplied air respirators. Building residents and other workers should vacate a building during spray foam installation and until the foam has finished curing and the building has been ventilated and thoroughly cleaned. Common industry practice is waiting 24 hours after completion of spray foam installation for re-entry. Offgassing from the SPF can occur for extended periods after installation. See the Process Chemistry tab for some chemicals that have been identified offgassing from closed cell SPF. 

A historical version of this CP is available here: https://pharosproject.net/common-products/2209563#contents-panel.