Hoist on Up
July 31, 2002
To meet the perpetual demand for safety and convenience, hoisting equipment continues to evolve. We recently spoke with a few of the companies servicing the industry to learn about the latest machines.
Saving Time and Money
Why do contractors need hoists? According to Josh Dunoff, president of Safety Hoist Co., Lafayette Hill, Pa., platform hoists provide an inexpensive way for contractors to lift heavy materials up to the roof.
“Having a hoist will give the contractor more flexibility in starting jobs. By being able to roof-load a job, they will not have to wait for material deliveries,” says Dunoff. “Also, they will not have to pay for rooftop delivery charges …. And [they] will not be wasting time and effort carrying material up a ladder.”
According to Dunoff, since platform hoists are smaller and lighter than boom trucks, they cause less damage to driveways and landscaping. They are also more mobile than a truck and thus allow the roofing material to be placed where it is needed on the roof, not just the spot where the boom truck can reach.
Another benefit to using hoists is that they provide a safer work environment. “Carrying material while climbing a ladder may be the most dangerous task in roofing,” says Dunoff. “According to C.N.A. insurance injury statistics, approximately 23 percent of workers compensation claims are as a result of falls and 30 percent of claims are soft tissue claims (resulting primarily from heavy lifting). By using a hoist, the amount of climbing and lifting is reduced, thus reducing workers compensation claims. Lower claims mean lower premiums.”
Also, the NAHB recommends climbing a ladder using a “three-point-contact grip.” That method requires two hands and one foot placed on the ladder at all times. This does not leave the contractor with a free hand to carry materials, but using a material hoist will eliminate this problem.
Hydraulic Hoisting Equipment
Hydraulic hoisting equipment is another option on the market. “With mechanical drive hoists, there are often complicated systems of belts, pulleys, clutches and brakes that can fail because of wear, or the buildup of dirt and other debris,” explains Jeff Small, All Seasons Equipment, Oakville, Ontario, Canada. “With the growing availability of hydraulic hoisting equipment, many roofing professionals are turning to hydraulics on their job sites for power, safety and versatility.”
One advantage to hydraulic equipment is the power it has. “With fingertip control and precision, loads can be lifted and lowered as well as swung in and out from the roof,” says Small. “The increased power of hydraulic systems has made highly portable units available with capacities of up to 2,000 pounds while running a single line. Being able to lift a ton on a single line at 170 feet per minute means more material can be lifted to the roof deck in less time.”
This is especially important when doing high-rise work. Doubling the capacity and reducing the number of lifts can save days of labor and prevent workers from being idle while awaiting materials on the job site.
Safety is another feature to hydraulic hoists. According to Small, hydraulic hoists use a power-up/power-down control system that prevents the operator from allowing the load to free-fall. The main benefit of this system is that it does not allow the machine to exceed the safe-load traveling limitations of the hoist design.
“With a mechanical hoist, loads can be allowed to free fall with the operator suddenly engaging the brake system,” says Small. “The resulting massive shock loads to the hoist frame can overpower the safety factors. This type of operation is impossible with a hydraulic hoisting unit.”
Small cites the double braking system employed on the winch as a critical safety factor. “The braking system requires a minimum pressure to open up and allow the drum to rotate. In the event of hydraulic failure, the brake immediately engages, stopping the load in place,” he explains. “If this system fails, a secondary brake engages after a 10-foot drop, securing the load. This double braking system is much safer than rope/band brakes employed on mechanical units.”
According to Small, with a powered system, the operator is able to conduct all hoist operations from a safe, secure location behind a fall protection system. The load can be lifted, swung in and lowered onto the roof deck before anyone comes into contact with it. “This differs from the mechanical hoist system where an operator must manually pull the load in over the roof deck,” he says.
Finally, Small extols the virtue of the hydraulic hoist’s versatility. With the swing-boom design that allows a load to be swung in to the left or right, use of a hydraulic hoist is not restricted by a parapet wall or other obstruction. “The hoists can be set up to swing loads into a more accessible location,” says Small. “This is especially helpful when doing multiple level roofs where the available space for the hoist may be severely restricted.”