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
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...
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