Manufacturers are improving light towers to meet the needs of contractors who work day and night.
So much is said about job-site safety in the construction rental industry that it's easy to think you've heard it all. The reality is, new safety issues frequently arise, and many times contractors look to rental centers for the solutions to safety concerns.
Job-site lighting is a perfect example. Jobs today have tighter deadlines and stricter regulations, causing contractors to work during nontraditional hours - in the early morning, late evening and into the night - when nature cannot provide adequate lighting.
In these conditions, contractors often turn to rental centers to provide an alternate source of light: portable light towers. But all portable light towers are not created equally, and many factors must be considered when selecting and setting up light towers to ensure the most efficient and safest job-site lighting.
What to look for Because light towers are often necessary obstructions on a job site, contractors need the most light from the fewest towers. To determine how much light a tower can deliver, look at the light source - the lamp and fixture. Most light tower suppliers recommend 1,000-watt lamps. The 1,000-watt units are cost-effective, durable and deliver up to 110,000 lumens in a perfect, nonreflective environment.
When placed in a coaxial (round) fixture, the lamp reflects light off the fixture surface, dropping light output far below the lamp's capability. Independent testing has shown that fixtures offering the most direct, nonreflective light output, such as parallel (oval) lamp fixtures, provide the most usable lumens directly to the job site.
Additionally, parallel lamp fixtures distribute light over the entire job site evenly. Coaxial fixtures typically produce spots of light - "hot spots" - that are extremely brighter than the rest of the illuminated area.
With space at a premium on job sites, more equipment can lead to congestion and unsafe conditions. To combat this problem, contractors look for compact light towers. Compact units save valuable space on job sites, which allows, for example, a contractor to close only a single lane of traffic, minimizing congestion associated with road construction and improvement projects.
Compact units are also lighter, leading to better maneuverability, and are easier to ship and store for rental centers and their customers.
How many towers? The Illuminating Engineering Society (IES) established guidelines to help contractors determine how many foot-candles of light particular job sites require. A foot-candle is the intensity of light per square foot of a surface area and can be measured with a light meter.
Job Site Foot-Candles Airport 0.5 to 2 Explosives Handling 30 General Construction 10 Excavation 2 Industrial Roadways 0.5 to 1 Material Handling 5 Loading/Unloading 20 Parking Areas 1 to 5 Piers 20 Railroad Yards 2 Quarries/Mining 5 Recreational 10 to 50
The number of foot-candles a light tower can provide depends on several factors. Are you working on black dirt, concrete or asphalt? A contractor might need more light towers to reach the recommended foot-candle measurement on black dirt than on concrete. Is the sky clear or cloudy? A clear, moonlit night might require fewer light towers than an overcast evening.
Every application must be evaluated with these considerations to determine how many light towers are necessary for each site.
Setting up When setting up a light tower, always level the unit completely before extending the mast. Position the fixtures at the highest location possible to minimize glare on the work surface. On typical job sites, the fixtures should be tilted 20 degrees toward the work area.
Contractors can reduce glare further by adding a visor to each fixture. A visor is a piece of aluminum bent to the shape or curve of the fixture to capture excess reflected light and direct it toward the job site and away from traffic and residential areas. Visors can increase a fixture's usable light by 13 percent. Most manufacturers offer visors as optional equipment.
Other safety considerations Just as job-site lighting is a key safety consideration, so is noise contamination. Adding another piece of equipment to an already busy job site can bring noise to a dangerous level. A light tower's noise level should be no more than 65 decibels. Many light tower manufacturers minimize vibration noise with heavy-duty enclosures and well-mounted engines. Some light towers also offer sound attenuation packages to reduce noise further.
Many light towers feature a mechanism that locks down the tower and prevents it from extending inadvertently when being towed. Other safety features include self-locking stabilizers and captive latches on the tower support. These latches eliminate the need for troublesome pins, resulting in a safer, simpler unit. Some light towers also feature a "ground rod," which grounds the units to protect operators from electrical shock.
Coleman Engineering
The Rite-Lite Series light tower delivers 4,000 watts of light and features a 30-foot, 360-degree rotating tower, a three-cylinder diesel engine set at 1,800 rpm and a 6,000-watt brushless generator. A full tank allows more than 60 hours of operation, the company says.
Boss Industries
The Tour is a 30-foot telescoping light tower that rotates 360 degrees and has four 1,000-watt metal halide lamps. The unit is equipped with a 6,000-watt generator (8,000 available), a 25-gallon fuel tank and a 10.5-horsepower Kubota water-cooled diesel engine (Isuzu available). A galvanized trailer frame, boom sections, outriggers and fenders are standard.
Terex
The TX3000 from Terex Light Construction is equipped with a 6,000-watt, 60-hertz generator and a 30-foot, cable-actuated rotating mast. The unit provides 4,000 watts of lighting capacity with four 1,000-watt fixtures. Powered by a Kubota three-cylinder diesel engine with a 30-gallon fuel tank, the TX3000 can deliver about 60 working hours before refilling,the company says.
Allmand Bros.
Port-A-Lite metal halide light stands are available in models PAL 1000W2, PAL 1500W2 and PAL 2000W4. These portable, high-intensity units feature Allmand's super high output (SHO) fixtures. The 1000W2 has one 1,000-watt SHO lamp and fixture, the 1500W2 has one 1,500-watt lamp and fixture, and the 2000W4 has two 1,000-watt SHO lamps and fixtures. The average lamp life exceeds 12,000 hours, the company says.
MultiquipThe new MLT-DA7 is a modular light tower that can be powered interchangeably by Multiquip's 6,000-watt 7000SS generator, 225-amp diesel-driven welder/generator, 250-amp gas-driven welder or any available AC power source. The unit operates at 65.7 decibels and features a quick-disconnect lamp system, a cable-grip strain reliever, a pivoting wire-rope anchor and a 30-gallon fuel tank. The towable unit's torsion spring-drop axle provides independent suspension.
Wacker
Wacker's trailer-mounted light towers, the LT 4 and LTP 4 (pictured), are equipped with masts that rotate 360 degrees and four 1,000-watt lamps to light up to 7 acres. The 30-foot units produce 6,000 continuous watts for 120/240 VAC single-phase use through two receptacles.
Ingersoll-Rand
The LightSource portable light tower from Ingersoll-Rand features a 6,000-watt generator, standard power receptacles and a 30-foot tower extension. The generator can operate four 1000-watt metal halide or high-pressure sodium floodlights for 68 continuous hours, the company says. The steel tower is a three-section mast that extends 12 feet to 30 feet and can rotate 360 degrees. The towable unit has a 3,500-pound axle for safe transport.
Amida
The Amida 500 is a compact light tower available with metal halide or tungsten halogen (quartz) floodlights. The unit plugs into any generator or 120-volt power source, the company says. A single hand winch extends the galvanized mast to a maximum height of 21 feet.
