An official website of the United States government.

Vacate and Safe Re-Entry Time for Spray Polyurethane Foam Application

Only workers wearing appropriate personal protective equipment (PPE) should be present during spray polyurethane foam (SPF) installation. It is not clear how much time is needed before it is safe for unprotected workers or building occupants to re-enter. Re-entry time is dependent on product formulation and other factors that affect the foam curing rates.

On this page: 

Vacate premises during installation

Building/home occupants and other workers should vacate during SPF installation

During SPF installation, other trade workers and building/home occupants should vacate the premises. Re-entry should be restricted until the product has finished curing, and the building has been adequately ventilated and thoroughly cleaned.

Building/home occupants and unprotected trade workers in buildings where SPF is being installed could be exposed both through their skin and through inhalation to residual vapors, aerosols and dust particles generated during the SPF installation process.

People who enter a building/home after SPF has been installed could be exposed to residual vapors from “uncured” foam and possibly dust particles bearing isocyanates if the foam was cut or disturbed and if adequate building ventilation and cleaning did not occur prior to re-entry.

Top of Page

Determining safe re-entry times

To determine a safe re-entry time for unprotected applicators, helpers, other workers, and building occupants, such as homeowners and school children, decision-makers should exercise caution and consult their SPF contractor for specific guidance in advance of SPF installation.

When determining a safe re-entry time, take into consideration vulnerable populations such as children. Children may crawl, roll, or sit on surfaces (i.e., carpets and floors) and play with objects such as toys where chemical dust or residues may settle. Children with asthma are an especially vulnerable population.

Re-entry should be restricted until the product has finished curing, and the building has been adequately ventilated and thoroughly cleaned.

Some manufacturers recommend 24 hours after application for the two-component high pressure "professional" SPF system for worker re-entry without the use of PPE and for re-occupancy by residents and other building occupants, but the recommended time may vary. Contact your manufacturer or supplier for specific guidance on ventilation time, re-entry time, and re-occupancy time for your specific product and scenario. Some manufacturers estimate that it can take approximately 8 to 24 hours to cure for one component foam, typically available in 12 oz. to 24 oz. cans. More research is needed to account for the potential variability of curing rates.

Get more information on ongoing research on re-occupancy times, product emissions, and ventilation rates through ASTM International Subcommittee D 22.05 on Indoor Air Quality. Exit 

If home or building occupants have concerns about: 

They should contact their contractor to ensure proper procedures and clean-up were followed. If their concerns are not resolved, affected parties should contact their local or state consumer protection office or contractors’ licensing board. Consumers can also file an online Consumer Product Incident Report with the U.S. Consumer Product Safety Commission on the website.

Top of Page

Return to the spray polyurethane foam (SPF) index page.