Spray polyurethane foam (SPF) roof systems are unique in composition and present roofing contractors with distinct worker health and safety challenges. Hazards from falls, fire, electricity and exposure to hazardous substances are found on nearly all roofing job sites, and SPF roof system installations are no exception.
However, SPF roof system hazards often are insidious, and necessary controls to prevent worker injury may not be readily apparent or may require solutions uniquely suited to SPF roof system installation procedures, materials and equipment.
An SPF roof system installation involves high-pressure spraying of a two-component mixture of chemicals applied by a worker (applicator) who typically moves backward along a roof surface. The mixture is applied in layers, or lifts. The spray rig that heats and delivers the chemicals is connected by hoses tended by another worker (helper) to a spray gun operated by the SPF applicator. As the mixture strikes the work surface, it expands and eventually hardens to its finished consistency after which a protective coating is applied by spray or roller.