March 1, 2012 by David Godkin
Our beginnings never know our ends. For John Grove it began back in 1967 when he watched in horror as two workers on a scaffold high above him at the legendary Hoover Dam caught the wrong end of a power cable and were electrocuted. Still shaken days later, Grove wondered how something like this could have happened on a supervised site.
Then he had an idea. Why not design something safer and more stable than scaffolding that also improved productivity. Together with two friends he purchased a small metal fabrication business, called it JLG Industries Inc., and began kicking around design ideas. Three years later, the world’s first aerial work platform (AWP) was born.
Today, AWPs play an important role at industrial and construction sites across North America. Scissor, straight and articulated booms are helping contactors lift workers and gear higher, while reaching in, over and around more difficult obstacles than ever before. Four manufacturers talked to us about what contractors should be looking for when purchasing or renting an AWP.
Before looking up, look down…
Most contractors who rent an AWP (generally preferred over buying) will know the conditions at the job site and consequently which lift will work best. They’ll know if it’s an indoor application, a two-wheel drive electrically driven lift will eliminate dangerous emissions. They will also understand that the machine’s size and turning radius will need to be appropriate for the building’s interior dimensions. More rigorous outdoor terrain will require four-wheel drive, says Genie Industries’ Chad Hislop, and oscillating axles to avoid spinning tires and ensure continued traction.
“Even with traction control systems, when you have a tire spinning in the air you’re still losing power. You’re not effectively putting that power to the ground. When the machine is stowed, active oscillating allows the front axle to pivot and make sure all four wheels are on the ground.”
Genie’s scissor and boom lifts (part of Terex’s AWP division) offer axle oscillation in both a stowed or elevated position, a “big deal”, says Hislop, because you need four wheels on the ground axles under all conditions. But Snorkel North America president David Smith says all this goes for naught if you haven’t adequately evaluated the ground conditions before selecting an AWP. In fact, he calls floor loading and the failure to adequately compact a job site so that a lift has a smooth, level surface to sit on “one of the biggest issues” facing contractors today. Municipal sidewalks, for example, are typically comprised of a three- to four-in. slab over plumbing and other services that can complicate the surface area beneath the AWP’s wheels.
“If those four wheels of whatever aerial lift you’re using are not stable and don’t have a good footing there, you’re falling over. We see that time and time again.”
It’s your rent or sales rep’s job to make sure that doesn’t happen, Smith adds. First by being fully up to speed on International Platform Access Federation (IPAF) standards for the safe application of aerial lifts, and second by adequately diagnosing ground conditions at your job site. But a knowledgeable sales or rental rep is no substitute for a well-informed customer, Smith adds; he recommends that contractors familiarize themselves with the AWP reference guides and check lists available at IPAF’s website, www.ipaf.org/.
Another key consideration, particularly for scissor lifts, is machine size and platform width. JLG global product director Jeff Ford says a large platform “will put more people and gear up into the air” and keep them there, minimizing down time and increasing productivity. Operator performance and productivity on a scissor lift are functions of platform space; you skimp on this at your peril, product specialists agree.
Now look up…look way up…
All agree what customers demand year after year are AWPs that are taller and can reach further than ever before. To that end, JLG introduced the 1500 SJ in 2011. At 150 ft., it’s “the largest telescopic boom ever created,” says Ford. It is ideal for multi-story office buildings, stadium construction and maintenance, petrochem and power plant construction. “Typically, you’re limited to 135 ft.; now you can get another story and a half up that building without using a crane.”
Genie’s boom lift product manager Mike Northcott reminds us, however, that there are trade-offs the higher you go. “When you go higher you have to add counter weight to the machine, for example. You may also have to increase your wheelbase by adding retractable or extended axles.” This in turn may require additional wide or heavy load permits when transporting the boom to and from the job site.
A telescopic boom is also at a disadvantage when you have to get up, over or around an obstruction such as a wall or building. That’s why Genie introduced the articulating boom back in 1985. Since then its booms have been lowered into Alaskan sulfur mines, used on Hollywood movie sites and as the inner workings of a giant-sized dragon puppet at Disneyworld.
The most fascinating application? Construction of a new research station in the Antarctica jacked up on steel legs to keep it above the snow and attached to skis for periodic relocation when the ice shelf breaks off into icebergs. To assist construction, British Antarctic Survey (BAS) bought two VGenie articulating Z-60/34 booms fitted with the Loegering QTS track system from Central Access, an aerial lift distributor in Nottingham, UK, acquired by AFI-UpLift. BAS settled on VGenie’s articulating booms, says Northcott “because it has incredibly low ground pressure,” and has the added advantage of being able to drive at height. The absence of outriggers also reduces overall work time, helpful in freezing weather conditions.
Never mind the Antarctic, says David Smith; weather performance is essential when buying or renting an AWP in Canada, too. By relying on live hydraulics instead of circuit boards he maintains that Snorkel’s lifts “function better” than other machines in -20 degree temperatures. This coupled with lower temperature viscosity oil, hydraulic warmers on all main fluid lines, glow plugs and block heaters for the engine keep the machine warm overnight so it starts up immediately the next morning.
Not to be outdone, Mayville Engineering Corporation (MEC) product support manager Jeff Smith boasts “an arctic package for those machines that are going way up north and working in 30-to 40-below temperatures, notably our Titan-S40.”
At the end of the day, it’s height and weight capacity that most customers are looking for. “Give me higher, give me bigger,” says Northcott, “That’s what they want.” “That’s a fair statement,” agrees Smith. MEC’s Titan boom features a 40-ft., 4,000-lb. capacity lift and a 22- by 7.5-ft. platform. At the same time, Smith offers one last bit of advice: when a rep talks about height make sure he’s talking about platform height, not working height. That goes for both scissor and boom lifts.
David Godkin is a B.C.-based freelance writer and regular contributor to On-Site. Send comments to email@example.com.