All roof system installations have common hazards, such as falls, that must be controlled. However, some unique hazards specific to spray polyurethane foam (SPF) roof systems must be assessed and managed on SPF roofing projects.
To complete an SPF roof system installation, workers use airless spray equipment to apply a two-component mixture to form the base of an SPF roof system. Airless spray equipment uses hydraulic pressure rather than compressed air in conventional spray equipment to apply the material to a roof surface. An airless pump pushes the SPF material through a hose and then through a fine hole in a spray gun tip, spraying the material in a fan pattern.
Generally, the advantage of airless spraying is the material is sprayed without altering its physical properties (as may occur when spraying with compressed air) to atomize the material, reducing viscosity by using solvents to thin it. The result is a more uniform application with consistent thickness and limited overspray.