Roofers are a pretty common sight, especially when the weather is mild. What we may not realize, however, are the health risks that are associated with working with hot asphalt. Roofers exposed to asphalt fumes may experience headaches, eye, nose, throat, and skin irritation, nausea, fatigue and drowsiness. These risks seem to be mild and transient.
But that’s just the tip of the iceberg. According to some studies, roofers may also have an increased risk of lung cancer; although there have been no definitive conclusions as of yet. If you add the possibility of looming cancer to the other less fatal irritation effects associated with hot asphalt work, it makes sense for both employers and employees to take steps to control exposure.
Before starting work, the contractor needs to ensure that workers have been properly trained in the hazards of applying hot asphalt and acceptable work practices. The contractor should also check that employees are using the appropriate personal protective equipment to reduce exposures to asphalt fumes.
Prior planning before work begins will help reduce workers’ asphalt fume exposure. Determine if it is possible to use a tanker to supply asphalt to the kettle or to the rooftop directly. If this is not possible, and a kettle will be used, place it where workers will be least exposed to the fumes. Keep the kettle away from air intakes, doors, and windows. Try to use roofing equipment and accessories that have lids to reduce exposure to fumes.
If possible, use an insulated kettle that is the right size for the job. It should have temperature controls and the right pumping capacity for its size. Inspect it to be sure that it is in good operating condition. Insulate the pipeline that delivers the hot asphalt to the roof.
Maintaining proper asphalt temperature is another way to reduce exposure to asphalt fumes. The equiviscous or application temperature (EVT), and the flash point of the asphalt can be found on the keg package or bill of lading. Once you have determined these guidelines, set the kettle temperature at the EVT plus 50°F. Periodically measure the asphalt temperature in the mop bucket. Make any adjustments to the kettle to maintain proper temperature. The appropriate temperature is the EVT plus or minus 25°F. The kettle temperature must also always be at least 25°F below the flash point to avoid fires and explosions. Use a hand-held or infrared thermometer to get an accurate reading.
Workers need to be trained to be continually mindful of safety when working with hot asphalt. They should place the kettle on firm, level ground to avoid spilling or tipping. They also need to be trained to put up warning tape, traffic cones, or signs around the kettle to keep others at a safe distance. They should reduce the number of times the lid is opened by filling the kettle to capacity when reloading. Workers should also check the temperature, stir, and skim when they reload. All workers must have, and know how to operate, a fully charged ABC-type fire extinguisher near the kettle.
During the actual application, workers should:
- Keep lids closed on rooftop equipment and accessories used to transport and apply hot asphalt.
- Stay out of the fume cloud whenever possible.
- Use buckets with half lids.
- Fill buckets only three-fourths full.
- Carry buckets on the down slope of the roof.
- Twist mops instead of pulling to unstick them from buckets.
- Twist buckets instead of pulling to unstick them from the roof.
- Minimize the time spent on their knees working with hot asphalt since exposures may be higher when closer to the fumes.
- Use long-handled tools whenever possible.