Published: January 2006
Mobility, stability and operation ease make self-propelled aerial lifts the fastest, most efficient, and safest way to raise workers, tools and equipment to elevated heights for electrical and datacom construction and maintenance. These versatile machines elevate quickly, and most models can be moved around job sites while platforms are raised. Rough-terrain models can be used outside or in buildings where floors have not been raised.
Aerial lifts allow personnel to be more efficient and to complete work faster, helping keep work on schedule. They contribute to job site safety by limiting the situations in which workers must climb structures or ladders while carrying heavy tools and equipment. They often eliminate the time-consuming and labor-intensive task of erecting and dismantling scaffolding.
There is a good selection of types and sizes of lift equipment available. Job conditions usually dictate the type and size of equipment best suited for a project.
Scissors lifts provide straight-up elevation, have the largest platforms and can support the most weight. Platforms can accommodate more tools and supplies than other types of equipment, reducing the need to make frequent up-and-down trips. Scissors lifts can be moved while fully extended.
Telescoping boom lifts provide height and reach with multisection booms, allowing platforms to go out and up. Telescoping models are usually the best choice when fixtures and equipment restrict placement of a lift.
Size and location of obstacles will determine the length of the boom needed, but a 40-foot boom machine should be able to provide reach and height to access the 20-foot-high light fixtures.
Articulating boom lifts have telescoping boom sections connected at individually controlled pivot points that add up-and-over capabilities to access places where scissors and telescoping booms cannot reach. Platforms are most maneuverable on this type of equipment.
A 30-foot articulated model should be sufficient to access the 20-foot-high fixtures in most situations. The operator can drive along a plant aisle and access lights on both sides of the row by up-and-over reach. Weight capacities of both types of boom lifts decrease as boom extensions increase.
For all types of lift equipment, work environments also influence choice of power sources. Smaller models use electric motors powered by rechargeable batteries.
Larger equipment uses gasoline, diesel and dual-fuel gasoline-propane engines. Liquid-propane emissions are cleaner than gas or diesel engines and are more common for indoor applications.
Jeff Ford, product champion at JLG Industries, said electric-powered scissors lifts are the most popular model for electricians.
“In fact, electricians are the largest single user category of this type of aerial work platform. Smaller models that can be driven through 32-inch doorways are preferred by many electrical contractors,” said Ford.
Genie Industries product manager Phil Harven said the company finds compact DC-powered scissors models the most popular choice with electricians.
“The range of widths and heights of available scissors is very complete,” said Haven. “Slide decks of today’s models are easier to use and are larger, and they have better electric drive systems.”
Models with 15- to 20-foot platform heights are used on many electrical projects.
“This is because they are lightweight, narrow—30 or 32 inches wide—and extremely maneuverable,” Haven said. “Electrical contractors like the 36-inch platform extension, which adds flexibility and efficiency. It gives the option for working solo or with a team of two on the platform. When a job requires a bigger platform deck and greater capacity or heights, larger models are available.”
Harven said electricians also like single-man vertical lifts that have compact bases and tight turning radii.
“Because of their versatility, articulated booms are more prevalent for outdoor work,” he said. “They service a different type of electric work—exterior fixture installations, exterior wire runs, lighting, etc. When working outdoors in rugged terrain, the active oscillation system provides improved traction, user confidence, greater utilization and productivity.”
Snorkel inside sales manager Leslie McHugh said job site conditions influence choice of aerial equipment, but also noted that smaller electric scissors models with platform heights from 19 to 32 feet are most popular for electrical work.
“Smaller, compact electric scissors are able to work in smaller spaces,” said McHugh. “Nonmarking tires are standard on these models for inside use. On all scissors, platform size is also a benefit for materials.”
Boom equipment offers more versatile working ranges. McHugh said important features on today’s lift models include ease of maneuverability, attachments and ease of maintenance.
“Pivot steering on small electric scissors and hard-wired systems for easy maintenance help increase productivity,” McHugh said.
While lift-equipment models sold today may look the same or very similar to those in service for several years, manufacturers continue to make improvements that make equipment more efficient and helps their users be more productive.
JLG’s Ford cited two examples, introduction of a line of scissors lifts using electric motors to drive the wheels rather than hydraulic motors and a scissors lift electrician’s package designed specifically for overhead electrical work.
Ford says powering drive wheels electrically provides double duty cycle—the length of time the machine can be operated before the batteries are discharged—of many electric scissors lifts.
“Using direct drive electric motors eliminates the inefficiencies of pumping hydraulic fluid through hoses to and from the reservoir to the hydraulic motors,” said Ford. “The efficiency of an electric drive versus hydraulic drive is about 65 percent versus 30 percent. In other words, scissors lifts with electric drive motors operate at twice the efficiency of machines that use hydraulic motor for their drive function.”
To increase duty cycles, manufacturers also are reducing the weight of equipment by using lighter but stronger alloys, by consolidating operating systems so fewer parts are necessary and by decreasing the hydraulic reservoir size, which reduces the quantity of fluid necessary.
They are also using precision bearings and more accurately machined scissors pins to reduce frictional drag.
“The bottom line is that electric powered machines with longer duty cycles are more economical to own and operate while being more productive for the workers that use them,” said Ford.
The optional JLG electrician’s package for scissors lifts includes a fold-out conduit rack, an electrician’s tree with spool holder and a workstation with an 8- by 20-inch fold-out workbench that has multiple, specially sized compartments for connectors and tools.
Tool holders can accommodate a drill, a reciprocating saw and a circular saw. An optional 12-volt plug can be added to charge cordless tools directly from the scissors batteries. On the larger scissors lift models, a rail-mounted 5-inch vise is included.
Ford said the package helps keep tools within reach and off the lift floor to reduce potential trip hazards. The conduit rack and wire spool holder allow more materials to be taken to the work area without consuming valuable platform space, reducing up and down trips.
JLG sells, rents and leases aerial equipment through authorized dealers that include equipment distributors and big box retailers. Financing is available through alternatives via JLG Industries.
Snorkel sells equipment directly and through dealers and offers financing and leasing programs.
Genie sells products through authorized distributors and offers financing and leasing programs through Terex Financial Services.
None of these three companies providing information for this report rent directly to end-users. However, all say the number of rental units continues to grow each year.
Smaller aerial lift models are widely available through conventional rental sources and larger units are carried by equipment rental specialists.
Aerial lift equipment is an important category of equipment for United Rentals Inc., the world’s largest rental organization, said Kevin Parr, New England district manager for high-reach equipment.
“In fact,” Parr said, “United Rentals has the largest aerial fleet in the world. Aerial equipment has become standard equipment on most every commercial or industrial project, and we rent electrical contractors everything from compact 19-foot scissors lifts to 100-foot plus booms.” EC
GRIFFIN, a construction and tools writer from Oklahoma City, can be reached at 405.748.5256 or firstname.lastname@example.org.