There are many factors to consider when planning an SPF high pressure installation. Will the work take place in an occupied building or a building under construction? Will the building be vacated? Will other trades workers be present at the time of application? Will the application take place indoors or outdoors? What is the size of the work area – a large open area or an attic or crawlspace with limited ventilation?
HVAC systems are typically shut down during some parts of roof preparation, as well as during application of primers, spray polyurethane foam, and coatings. System shut down stops the drawing of dusts, aerosols and/or vapors into interior spaces. Once the HVAC system is shut down, seal the air intakes with plastic sheeting and tape, which will prevent dust and spray from entering the intakes. Keep the plastic sheeting in place at least several hours after the spray application is completed, typically 24 hours or more; a longer period may be appropriate for coatings, depending on when the coatings have hardened or set and are no longer emitting vapors. The HVAC system should not be restarted until appropriate time has elapsed and the plastic sheeting and tape is removed.
Consider the following practices when preparing a site for an SPF high pressure application:
- If the entire building is not vacated, consider the potential for SPF chemicals to migrate to other floors. Containment and ventilation methods may help prevent migration. Discuss with property management or other contractors which floors will be occupied.
- If local exhaust ventilation and containment methods are not used, establish a work zone around the work area to protect adjacent workers. The distance between the work area and adjacent workers is typically 25 feet, but depends on several factors, including but not limited to the volume of SPF applied, the area covered, and air movement. Signage may be used to communicate access restrictions. Consider limiting access to persons wearing proper personal protective equipment or trying to schedule other trade workers at times when SPF application is not underway.
- Before beginning work, designate an area for putting on and removing PPE.
- Determine in advance the potential for overspray damages. Have a plan in place to address overspray damages to adjacent property. Train all employees in overspray prevention.
- Identify and protect surfaces that could be damaged (e.g., windows, doors, equipment, or building exterior) in advance of application.
- For work outdoors, take wind direction into account for all spraying operations. Note that for a job that takes place over several days, the wind direction may change and the work area should be adjusted as needed. In slightly windy conditions, use windscreens.
- Do not spray foam or coatings in excessively windy conditions. Sustained wind speeds or gusts of about 15 mph (24 kph) make controlled application more difficult.