Solution Summary: Prototype Spray Polyurethane Foam (SPF) Spraying Booth
The SPF spraying booth is an engineering control developed by NIOSH. It uses Prevention through Design (PtD) principles to reduce exposure to SPF on construction sites, particularly in buildings. Exposure is reduced by isolating the area where SPF is applied. Isolation is needed because SPF chemicals can migrate between the floors of a building and affect the health of other workers not involved in SPF application.
SPF is applied in buildings to create air barriers and to insulate roofs, walls, and the building envelope (Figure 1). While SPF offers advantages like lower construction costs and increased energy efficiency, the application process can pose a health risk to workers. Any kind of exposure to SPF (e.g., breathing, skin contact, eye contact, or ingestion) could potentially threaten one’s health. Exposure to SPF chemicals can cause skin and eye irritation, lung damage, asthma, and other breathing problems. Exposure can also result in sensitization. When workers become sensitized, even very low levels of exposure can trigger health problems. As a result, there is no recognized safe level of exposure for people who become sensitized to SPF chemicals.
Figure 1. Applications of SPF in the construction industry
In 2009, the Environmental Protection Agency (EPA) created a workgroup with OSHA and NIOSH to address workers’ exposures to SPF chemicals. The workgroup developed guidelines for SPF application that can be used to train workers. Training workers and using singular controls, like those shown in Figure 2, is helpful, but more comprehensive solutions are needed, especially for people who are not directly involved in the application process.
Figure 2. Singular controls for SPF application (left image: plastic sheeting to cover wall studs and metal grating to control expansion of foam; middle and right images: air movers to exchange air in the spray zone)
According to NIOSH, SPF vapors can easily be transferred to other parts of the building even with conventional controls in place. Therefore, a prototype SPF spraying booth was designed and developed by NIOSH to provide a thorough solution that can minimize the risks of SPF to all workers. This can be considered a Prevention through Design (PtD) solution because it tries to solve a problem by adding a safety feature before construction begins. As shown in Figure 3, the prototype consists of PVC pipes and fittings, polyethylene sheeting, poly-hangers, foam pipe insulation, and a duct collar. (http://www.sprayfoam.org/files/docs/2011/Agency%20Report%20-%20NIOSH.pdf)
Figure 3. Prototype SPF Spraying Booth
This solution offers several advantages, including:
• Complete separation of the application zone from adjacent work zones
• Direct airflow from clean source to contaminated zones
• Filtered air
• Negative pressure for easier ventilation
• Flexibility for various job sites
• Low cost (a study in 2011 estimated the materials would cost $755).
Considering PtD solutions like this spraying booth during the planning and design phases of building projects could assure safer environments for all workers during construction.
Using any chemical on construction job sites, especially in closed projects like buildings, could adversely affect workers' health. Workers can be exposed to SPF vapors and mist during spray application and also SPF dust when trimming, cutting, and scraping foam that has cured. SPF particles can spread to other areas of a building, away from the application zone, and expose workers not using appropriate personal protective equipment (PPE). Exposure to SPF chemicals can cause serious health problems, including permanent lung damage and asthma, a potentially life-threatening disease. Workers affected by SPF exposure are often forced to leave their jobs to prevent worsening of respiratory symptoms. Following manufacturers' guidelines, providing enough ventilation, and using appropriate PPE can reduce the risks significantly for applicators (for more information: http://www.spf.basf.com/DOCS/SFC_InstallationGuide_v9.pdf). However, solutions like the SPF spraying booth are needed to reduce the risks to nearby workers not directly involved in applying SPF.
How Risks are Reduced:
The SPF spraying booth separates the work area from nearby work zones while providing ample ventilation for SPF applicators inside the booth. The materials to build the spraying booth, such as PVC pipes and polyethylene sheets, are easy to find and available in a range of sizes. They are also lightweight and easy to move. Design teams should consider building sizes and application areas when suggesting their ideas to contractors early in the design phase of a project to reduce the risks before construction begins.
Effects on Productivity:
The effects on productivity depend on the contractor’s safety policy. If a contractor’s policy forces them to close nearby areas in the job site during SPF application, then use of a spraying booth could avoid the shutdown and improve productivity.
The effects on productivity may also depend on the mobility of the booth, installation time, and mobilization time between different locations.
- Although workers typically have higher exposures to SPF than homeowners and consumers, reducing worker exposures is likely to reduce exposures for homeowners as well, especially if it's a maintenance project.
- Applying SPF requires sufficient PPE and follow manufacture's guidelines.
Behzad Esmaeili, Ph.D. - University of Nebraska- Lincoln
Pouya Gholizadeh - University of Nebraska- Lincoln
As each building project may need a unique booth, project teams should consider this as a Do It Yourself type of solution. The required material, however, could be found in building material and supply stores such as "The Home Depot" or "Lowes". For More information on assembling the booth, look at the pages 44-48 of the this PDF: http://www.sprayfoam.org/files/docs/2011/Agency%20Report%20-%20NIOSH.pdf