| Industry practice emphasizes the importance of having unprotected trade workers adhere to the manufacturer recommended re-entry time and ventilation process and the general public or building occupants adhere to the recommended re-occupancy time and ventilation process. |
| || RE-ENTRY TIMES |
| Re-entry times recommended by most spray foam manufacturers typically falls between 4 - 8 hours after the SPF application is completed to be within an acceptable range for human exposure without wearing PPE provided the area is properly ventilated. A minimum outdoor air exchange rate of 1 ACH (air change per hour) is recommended during this period. |
| The re-entry times can be decreased with increased ventilation rates. Some manufacturers have completed full scale testing and research evaluated by credible third party chemists and toxicologists that has confirmed re-entry times as low as 1 hour with an outdoor air exchange rate of 10+ ACH. |
| || RE-OCCUPANCY TIMES |
| Re-occupancy times have building occupants wait for a minimum of 24 hours after the SPF application is completed to re-occupy the area. Ventilation at a minimum rate of 1 ACH should continue for the full 24 hours. Re-occupancy times are most applicable to retrofit applications given that SPF is generally installed in new construction significantly before the building is occupied. |
| || PREVENT EXPOSURE |
| Post-spray emissions from recently applied SPF have been shown to be generally very low. However, it is very important to follow the manufacturers recommended re-entry times to determine when it is safe for SPF applicators, helpers and other trade workers to return to areas where SPF has just been applied without wearing PPE. |
