Doosan Portable Power and Allman Bros. Inc. each manufacture generators, light towers and air compressors. Pictured here is a Doosan LCV light tower.
Many people identify construction projects by the big, heavy equipment operating around work sites, such as earthmovers, paving machines and cranes, but just as important to any building effort — from grading and clearing jobs all the way up to girder installation — are the less obvious machinery. Portable light towers, air compressors and generators fall into that category.
Without this equipment, projects would become costlier, more difficult and more time-consuming. Night crews on highway projects around the nation utilize light towers for their work. Often as high as 23 to 25 ft. tall, they target light to a specific area with minimal glare to avoid distracting passing vehicles.
A generator or, in many cases, multiple generators, can provide a power source where electricity is difficult to access. Once tied into an electrical source via cables by an electrician, they provide power for an array of on site uses.
Air compressors, too, have many applications in construction, including powering jackhammers and sand blasters, as well as blowing out pump lines and helping crews stripe newly-painted roads and highways.
Doosan Portable Power and Allmand Bros. Inc. each manufacture all three of these construction-site staples, while Terex/Genie is one of the industry leaders in light-tower production, according to the company.
Most of their customers are rental dealerships who distribute the equipment to the construction companies on each project. Each product has proven to be durable and reliable despite heavy use and, if serviced and maintained well, have a high resale value.
Designers Always Strive for Innovation
Each of these products have been in use for decades, but despite their simplicity, they are continually improved upon by their manufacturers. Engineers and designers are driven to innovate these products to help their users save time and money.
Environmental concerns also are among their customers' wants and desires, as most light towers, generators and air compressors run on diesel fuel.
“I think the big things we are all trying to do as manufacturers is to enhance the run time on all of our products to make them more durable and reliable and, hopefully, as cost-effective as possible,” explained Todd Howe, Doosan's product manager for light towers and generators.
He cited the use of telematics and the ability of these machines to provide data on their performance to their owners as a continually evolving technology.
“Most of this equipment is owned by rental companies and they are responsible for the maintenance, so if a machine can proactively tell them when something may be going wrong with it, chances are the rental firm can have a chance to fix it before the customer even knows he has a problem,” he added.
A ubiquitous and essential piece of equipment for use on most nighttime construction projects, light towers also can be found at mining and oil field sites.
These simple machines are high-volume, low-cost products in rental applications, according to Howe.
“Despite the fact they are low-cost, relative to other construction equipment, light towers have received almost a disproportionate share of innovation over the last several years,” he continued. “As an example, 10 years ago they only had lay-down lighting masts that, in the transport position, was horizontal and the lamps hung off the back of the truck. Today, though, there has been a transition to vertical mast towers even while in transit.”
The obvious benefit of vertical lamp masts is, of course, that the customer can fit more light towers onto a truck. The masts come in five sections that nest within each other and can telescope into their raised positions.
Efforts also are underway to reduce the footprint and weight of the light tower units by transitioning from steel-bodied enclosures to ones utilizing composite materials, including plastics.
The objective is to give light-tower customers the longer run times they ask for from these diesel-powered machines.
“Product engineers spend all their time looking for creative ways to package even more fuel onboard to extend the intervals between servicing and re-fueling,” Howe explained.
There was general agreement among product managers from all three light tower manufacturers that advancements in light-emitting diode, or LED, lighting is an important and emerging technology in the product's evolution. Noted for their energy-efficiency, LED lamps have already started to overtake the metal-halide lights used for decades on light towers, just as LEDs have been replacing incandescent bulbs in the home for the last several years.
Historically, light towers used metal halide lamps with around 400,000 lumens and 4,000 watts of electrical power consumption. They are still used by light tower makers and sold alongside LED units.
“But as the performance of LEDs increase and the cost continues to be more affordable for rental scenarios, we predict there will be an inflection point where LED lights provide the most value to our rental customers,” said Josh Taylor, Genie product manager of Terex AWP.
Today, LEDs are being developed and sold that rival the brightness produced by metal-halide lamps, but with a power consumption of less than 1,000 watts.
That increase in electrical efficiency directly impacts the amount of fuel a light tower consumes in operation and makes LED units an attractive choice for customers wanting to keep costs low.
“LED lights consume about 25 percent of the power that metal halide lights do, so LEDs also play a key role in any efficiency improvements of light towers,” Taylor added, “and, lower power requirements open the door to smaller engines or other alternative power sources.”
Brett Shive, senior field technician at Allmand, agreed and added, “We use a 1,250-watt metal-halide bulb, which is our brightest, but as LEDs get stronger and better they become more efficient, so we want to try and use them as much as possible. LEDs use less energy and all our engines are extremely fuel efficient and they will continue to get better.”
“We are seeing LEDs being employed more because they can produce a more diffused, glare-free lighting,” Howe said. “They illuminate with a softer light that is able to be focused into a working pattern that puts the light where it is needed and reduces light pollution and glare a good bit.”
He said the biggest impediment to LEDs getting widespread application until now has been their cost, but with improvements in their design phase, costs reduce every year and their performance increases by 30 to 40 percent.
Finally, from a research and development standpoint, energy storage should become more refined in the next several years and offer a potential application on light towers, according to each of the product makers.
Howe believes that battery banks in the light towers can potentially be made to store extra energy produced by the generating system, with the capability to shut the engine off when the energy storage is full, thus extending the fueling interval and the run-time even further and, in turn, reducing costs.
According to Terex/Genie's Josh Taylor, “The power density of lithium-ion batteries could conceivably make emissions-free light towers viable from a usability standpoint.”
General contractors tend to make mobile generators among the first things they bring to a construction site as utility power is often not present.
Once they are operational, they can power a wide range of equipment, depending on their size and kilovolt-amps (kVA), the maximum power output from a generator. For example, a Doosan 25 kVA generator can power a whole home with everything turned on. By contrast, the Doosan 570 kVA unit will, in scale, run the entire neighborhood, according to Howe.
In construction, cord and plug tools, jobsite trailers and water management pumps run off generators, as well as tower cranes. At excavating and quarry sites, generators often operate mobile crushing and conveying units, too.
“They are site specific and that is why they are always sized to what the project needs from them to be and what the logistics of the site are,” said Howe. “Sometimes a big generator can handle a large site and sometimes a large site needs four or five smaller gens to minimize the cables running across it.”
He added that he has lately seen a bigger request from customers to be able to connect multiple generators together to form a network on site. With parallel gens, the control systems need to be able to communicate with one another and to precisely synchronize the power from one generator to the next. Otherwise, serious issues can arise with phase imbalances and power importing from one generator to another.
“So, to get them to behave nicely they need to have fairly sophisticated controls to make sure they all act as one unit,” Howe said.
Generators are used a bit differently than the other two products in that they usually operate 24 hours a day. As a utility source, once they are put in their application they only shut down for service and maintenance.
Because diesel engines power construction generators, as well as light towers and air compressors, manufacturers have spent a lot of time in the last several years designing machines that meet the federal government's Tier 4 final emissions standards.
Now, with most generator models within or near compliance, engineers and designers are focusing more of their attention on improving horsepower, fuel efficiency, run time, durability and reliability.
“The next 'big thing' we are looking at with generators are extended servicing intervals,” Howe said. “Today, our Doosan gens are at a 500-hour maintenance interval and we want to double that to 1,000 hours. That means a lot of work with our engine and component manufacturers and partners to hit that mark.
“Down-time on a generator is a bad word, maybe more than anything else in the rental world, so our focus is to keep the power running and make it something the customer doesn't even have to think about.”
Shive, too, believes technology will soon deliver on extended service intervals and predicts better fuel efficiency from generators, as well as larger fuel-tank capacities.
“All of Allmand's units run more than 24 hours, some up to 48 hours on one tank,” he explained. “I think they will eventually go even beyond that to as much as 60 hours, anything to keep them on the jobsite longer without constantly bringing in a tanker to fill it with fuel again.”
In addition, he expects to soon see some generators get larger, into the 200 to 300 kVA range.
“Look for all manufacturers to go with fully digital displays on their gens, too,” he continued. “That is something our customers are requesting more. The analog gauges were great because they were simple, but the younger workforce coming in has grown up on digital. Plus, the new digital controls allow them to access more useful information.”
Besides the familiar uses of air compressors on construction projects, Doosan and Allmand Bros. supply this equipment through rental companies to end-users on a range of other jobs.
“Many are shipped to the Gulf of Mexico where efforts are underway to bring many older, unused oil rigs back on line,” explained Jeremy Bailey, air products manager at Doosan. “Swimming-pool contractors will use air compressors to spray gunite, a cement, sand and water mixture, onto the form of a pool under construction. Some painting companies will use compressed air to paint large buildings and bridges.”
Moving through the Tier IV compliance process gave air compressor manufacturers the chance to design the engines to be electronically-controlled, which, like the other products, provides a wealth of data to the rental companies that service the machines. As a result, remote monitoring and connected machines have only recently come on the market.
“We can see exactly what the engine is doing, how heavy it's loading, what temperature it's running, etc.,” Bailey said. “The trend from Doosan and our competitors, as well, is to make smarter, better-connected machines using that data via telematics. Going forward, you are going to see more integrated technology.
“That information is so valuable in helping us create longer maintenance intervals. We will see much more of this integrated technology.”
He said longer maintenance intervals and the ability for GPS software to perform tasks online, such as scheduling an equipment-service appointment, are still on the drawing board and may not be available for another two years.
“Air-compressor designs will continue to focus on ruggedness, reliability and being among the quietest machines on a job site,” added Brett Shive at Allmand. “More digital controls all in one location is important to make them easier to use. Their screen lets you scroll through quickly and find the info you need.”
Like the other makers, Shive said Allmand also engineers its units to bring down fuel consumption and emissions.
The capacities of air compressors are commonly measured in pounds per square inch (PSI).
“All of our models are at 100 PSI, but we know customers want a higher output and we are working toward that,” he said.
Finally, Allmand and Doosan are continuing to make their air compressors smaller to improve fuel efficiency, while at the same time making them easier to service.
“We have better cooling and getting that into a tighter spot is easier now because of the better electronic controls and power-dense engines,” Bailey explained. “We can get the same power from a 4½-liter engine now as compared to a 6-liter a decade ago.”
By letting the market drive the demand for technological advances in light towers, generators and air compressors, these products will continue to evolve in efficiency, durability and reliability to keep their costs down for customers.