When you think about light towers, images of outdoor sporting events and concerts quickly come to mind. But the list of applications and events requiring the use of portable light towers is much more extensive. They can be seen working on various construction sites involving roadway expansion, material handling and repair activities. You can even find them providing light for open pit mining, loading and unloading cargo at airports, emergency rescue operations and temporary parking areas. So, once a contractor, company, group or individual decides they need a light tower, what can they do to ensure they choose the right type?
“There is a multitude of factors to consider,” says Rita Moore, marketing manager for Ingersoll-Rand electrical products. “You need to determine the size of the area that needs light and whether the entire area needs constant light or if the light towers can be moved around the area as needed. You also need to anticipate the site conditions. For instance, if it's going to be foggy or dusty, you may want to consider a different type of lamp.”
Being aware of the advantages and disadvantages associated with each lamp/bulb type will prove to be helpful in the selection process. There are two types of high intensity discharge lamps primarily used in North America with diesel-powered light towers for general lighting applications. First, there is the metal halide lamp. A 1,000-watt metal halide lamp provides an average of 88,000 lumens. Its advantages include high lumen output, good color rendition and overall lighting. Its disadvantages include medium lamp life and long restrike time. Restrike time is the amount of time it takes to reach full illumination after the light has been turned off and on again. Metal halide is the most common lamp type throughout North America and other areas of the world where power frequencies are 60 hertz.
The second option is the high-pressure sodium lamp. A 1,000-watt high-pressure sodium floodlight has an average of 126,000 lumens. Its advantages include high lumen output, low lumen depreciation, minimal glare and fast restrike. The disadvantage is a higher initial cost. Because of its soft orange color rendition, a high-pressure sodium lamp is ideal for foggy or dusty environments.
The floodlight is composed of the lamp and luminaire. Understanding the differences in luminaires is also key in choosing the right light tower. The luminaire serves a variety of purposes. It houses and protects the lamp/bulb, distributes the light, connects the lamp to the power supply and provides the mechanism to position the light. The National Electrical Manufacturers Association has classified floodlights by assigning a number to the horizontal and vertical limits of a floodlight's beam spread. For instance, a NEMA 1 classification means the floodlight has a beam spread of 10 to 18 degrees. Classifications used in reference to light towers include NEMA 3 (29 to 46 degrees), NEMA 4 (46 to 70 degrees) and NEMA 6 (100 to 130 degrees).
“Customers need to know the size of the area they want to cover and how bright it needs to be,” says Charlie Pevorus, IRES rental manager, East Hanover, N.J. “IR light towers have a NEMA 6 rating and are designed to cover a large area.”
Another basic component of all diesel-driven, portable light towers is the winch-operated mast. Designed to provide versatility and the best light coverage, most masts extend 10 to 30 feet. The height of the mast as well as the angle of the luminaire will have an additional impact on the distribution of the light and the total area illuminated at the job site.
The Illuminating Engineering Society has developed the recommended levels of illumination for various applications. The chart to the left is a sampling of key applications and recommended levels of illumination in foot-candles.
“When choosing a light tower, a customer should inquire about fuel tank capacity,” Pevorus says. “I would say it is the second most important thing to consider, the first being the size of the area. The IR light towers are equipped with a 30-gallon fuel tank, which allows the light tower to run approximately 68 hours. You're going to need that kind of longevity for most applications.”
Pevorus also suggests that customers consider what activity will be going on in the area when determining the amount of illumination. “If you're talking about lighting up a football stadium, you obviously need ample light so that the players and spectators can see exactly what is going on,” Pevorus states. “If you're lighting up the parking lot outside the stadium, you could go with lighting that is less intense. It all depends on the situation. As long as you know the size of the area, the type and duration of the project, you should be able to choose the right light tower for your specific application.”
Amy Hopkins is a copywriter for Two Rivers Marketing in Des Moines, Iowa.
Once you know the number of foot-candles, you can use this rule of thumb calculation to determine the number of floodlights required for the application.
A. Determine intensity required (foot-candles)
B. Determine the area to be illuminated (length × width)
C. Decide the light source desired (MH, HPS, TH)
D. Determine the area illuminated per floodlight from the “Lighting Capacity Chart”
|Type||Avg. foot-candles||Sq. feet||Sq. meters|
|Number of floodlights required = A × B/.5D|
Nightbuster light towers from Magnum Products Inc. are equipped with quick disconnects on the light fixtures. Removal of the light fixtures from the end of the mast prevents stone damage during transit and accidental damage during storage. The fixtures plug into the power distribution box and screw tight to form a weatherproof seal. When the fixtures are removed, they can be stored inside the enclosure on the 5000 series light towers or stored on the mast on the 3000 and 4000 series light towers.
www.magnumproductsinc.com • 800/926-0201
RS # 154
The TML-4000N and TML-4000 trailer-mounted light towers from Genie Industries feature a narrow 54 and 70 inch width, respectively. The towers have tilt-actuating systems that provide the ability to vertically aim all four lamp fixtures from ground level, significantly reducing the need to lower the tower in order to re-aim the lamps. The products have 6-kilowatt generators powered by Deutz 3-cylinder 14.75-horsepower water-cooled diesel engines. The TML-4000N has a 30-gallon fuel tank that runs continuously for 60 hours between refueling while the TML-4000 can run 100 hours between refueling.
www.genielift.com • 800/536-1800
RS # 155
The new Allmand 15330 and 20330 portable light towers are available with four- or six-SHO fixture configurations carrying metal-halide or high-pressure sodium lights. The light towers are powered by an 1,800-rpm, 32-horsepower Isuzu 4LE1 liquid-cooled diesel engine. Corrosion- and dent-resistant molded fenders and heavy-duty enclosures prevent dents, rust and corrosion while increasing durability. The models' outriggers and tower support feature a captive latch that eliminates problems associated with troublesome pins.
www.allmand.com • 800/562-1373
RS # 156
The LightSource portable light tower from Ingersoll-Rand is equipped with four 1,000-watt metal halide lamps in a NEMA 6 design for large area coverage. Aluminum reflector housings and tempered impact-resistant twist-lock connections provide protection and increased durability. The tower is designed for easy extension with dual, hand-operated winches with a patented automatic safety brake. The 3-section telescoping mast extends 12 to 30 feet and can be retracted and stowed horizontally for travel. With the outriggers extended and all jacks down, the product can withstand winds up to 65 miles per hour.
www.irco.com • 800/526-1090
RS # 157
The new MLT-KD1800 from Multiquip is powered by a 3-cylinder Kubota D-905 engine. The generator end provides 6 kilowatts of power. As part of the unit's unique modular system, the quick-disconnect lamp system allows easy, fast light attachment and detachment to facilitate repair, assembly and transport. The 50 inch wide unit is engineered to withstand rough transport and can be used on uneven terrain and in winds of up to 72 miles per hour when deployed with gensets. Zinc-dichromate tower sections, outriggers and socket tubes reduce corrosion and prolong life.
www.multiquip.com • 800/421-1244
RS # 158
Two engine options are available on all Wacker light towers: a 12-horsepower Kubota and a 16-horsepower Isuzu. Depending on needs and budgets, contractors can choose between a power or manual winch system. Standard models are 68 inches wide, and the wide body model measures 82 inches. Standard features on the light towers include four 2,000-pound rated galvanized leveling jacks, zinc-coated outriggers spanning 11.5 feet, lockable full-side swing doors with holding latches, a 360-degree rotating mast, a galvanized mast tube, a fully equipped control panel and an elapsed hour meter, and DC volt meter.
RS # 159
The Coleman RL 4000 provides cost effective mobile, trailer-mounted floodlighting for nighttime maintenance, construction, mining and emergency municipal work. Four thousand watts of light illuminates 5 to 7 acres. Dual self-braking winch design easily and quickly raises the 30-foot rotating tower. The light has a quiet operation as low as 71 dba at 23 feet.
www.colemanengineering.com • 800/228-6444
RS # 160
The BD1000-MH single 1,000-watt system from Bull Dog Power Products lights up almost two acres of land and plugs into any 15-amp, 120-volt power source. The unit folds down to 19 inches high, allowing it to fit into almost any car trunk. Models ranging from 1,000- to 3,000-watt single and double units are available in yellow or white. Features include shock absorber light heads, weatherproof on/off switches, universal super-tuff steel generator bracket, all-terrain pneumatic tires and revolutionary tire brakes.
www.bulldogpower.com • 800/466-1643
RS # 161