Solution Summary: Work Zone Lighting
Work zone lighting is an engineering control used to create safer working environments through illumination of areas with less than adequate lighting. The lamps use halide, halogen, or hydrargyrum medium-arc iodide (HMI) bulbs to improve lighting and reduce the likelihood of accidents or injuries on jobsites. Using trailer mounted, light tower, or balloon lighting will greatly increase awareness of surroundings and create an easier work environment in which to maneuver. Another important reason for illuminating the work zone is to make others aware of the presence of the workers. Reflective clothing should be used in combination with the lighting. The light shining on the workers wearing reflective clothing makes the workers visible to other workers, equipment operators, and passing motorists. Consideration should be given in the design of work zone lighting to select, locate, and orient the lights such that glare is minimized. With a well-lit work environment, tasks can be completed more safely, confidently, and efficiently as less time and energy will be spent on injuries and worrying about objects or obstructions due to poor visibility.
Working at night or in poorly lit areas may make a job more dangerous and lighting is recommended for low visibility work environments. Through the use of work zone lighting, work area safety is improved and the risk of injury or death is reduced. Even with work zone lighting in place, workers still need to be observant of their surroundings and exit any areas that they believe to be unsafe until the problem is corrected.
Lighting is often rated in lumens, which is a measure of the amount of light emitted from the source. Work zone illuminance requirements or specications are typically given in foot-candles (1 lumen per square foot) or lux (1 lumen per square meter). One foot-candle is equal to 10.76 lux. As the distance from a given light source increases the illumination provided decreases because the light is distributed over a greater area. Illuminance can be increased by providing more or brighter lights or by decreasing the distance between the light and the work area.
Allmand Portable Light Tower - Night-Lite PRO II V-Series
- Height: 5 feet 9 inches to 30 feet
- Weight: 1,650 pounds
- Fuel: diesel
- Fuel Capacity: 30 gallons (up to 65 hours of operation)
- Light Emission: 600,000 lumens
- Lighting Type: four 1,250 watt metal halide bulbs
Multiquip Inc. GB43LED 4-Spotlight Projection Lighting
(Photo courtesy of Multiquip Inc.)
- Four-stage mast extends up to 17.1 feet
- 40,000 hour lamp service life
- Lifting hook for easy transport
- Immediate strike/re-strike operations
- Shatter resistant lamp lenses
- Industrial mechanical safety winch
- Each 300W lamp can be set to multiple directions
- Industrial zinc-plated steel cart with off-road puncture-proof tires
Baldor Light Tower
- Height: up to 30 feet
- Weight: 1,800 pounds (without fuel)
- Fuel: diesel
- Fuel Capacity: 50 gallons (up to 100 hours of operation)
- Lighting Coverage: 5-7 Acres at 0.5 foot candles
- Lighting Type: four 1,000 watt metal halide bulbs
- Sound Pressure Level: 72 dBA at 23 feet (OSHA’s Permissible Exposure Limit for an 8-hour time-weighted average is 90 dBA)
Wanco Portable Light Tower
- Height: 12 feet 6 inches to 30 feet
- Weight: 1,800 pounds
- Fuel: diesel
- Fuel Capacity: 30 gallons (60 to 70 hours of operation)
- Lighting Coverage: 7.5 acres at 0.5 foot candles (5.4 lumens/m2 at 30,400 m2)
- Lighting Type: four 1,000 watt metal halide bulbs
- Sound Pressure Level: 71 dBA at 23 feet (OSHA’s Permissible Exposure Limit for an 8-hour time-weighted average is 90 dBA)
Dark or dimly lit work areas create a risk to workers. Worker injuries and fatalities are increased when adequate lighting conditions are unavailable. Many factors must be considered when planning for nighttime construction work, including the location of the work site, the surrounding environment, number of workers present, effect of nearby traffic, and the type of work being performed. Work zone lighting lighting can be used to provide the optimal amount of light (illuminance) for construction areas creating a safer work environment.
Injury and death rates of workers are steadily increasing for roadside work zone areas. Unfamiliarity with the area, reduced visibility, traffic congestion and distractions are likely the cause of these accidents (Berces). According to the National Institute for Occupational Safety and Health NIOSH, from 2003-2007, 639 workers were killed in road side construction related accidents. The number of worker injuries and deaths in the U.S. caused by insufficient lighting continues to increase. The CDC has recognized that work zone standards need to be improved (CDC, 2013).
Increased traffic congestion, lane closures, daytime road work increase the risk of accidents for both motorists and road-side workers. Evening and nighttime work solves traffic congestion issues, but creates problems of low visibility as decreased illuminance results in unsafe conditions (CDC, 2013). To reduce the risk for injury due to low visibility, work zones should be provided with adequate lighting to illuminate the work area. Tower lights are commonly used to solve this problem but may produce glare which becomes another risk factor causing decreased visibility to drivers and workers. A relatively new form of tower lighting, known as balloon lighting, is another option that significantly reduces glare, while still providing sufficient illuminance (Hassan, 2010). Balloon lighting units deliver 360 degree illumination without hot points so workers can look directly at the balloon without straining their eyes.
How Risks are Reduced:
These lighting units reduce the risk of injuries and accidents by helping to ensure that adequate lighting is provided in work zones. Using trailer mounted lights, light towers, or balloon lighting will greatly increase awareness of surroundings and create an easier work environment in which to maneuver. Selection of the amount of light to provide should also give consideration to the amount of surrounding light. If the work zone is in a location where there is little or no background light (e.g., a rural work zone), then a lower amount of light will be needed than if the work zone is in a location where there is much surrounding light (e.g., an urban area). In an urban area, the additional light provided by the temporary work zone lighting should make the workers and work area stand out from the background lighting. Workers should still be observant of their surroundings and exit any work areas that do not seem safe until the problem is corrected.
While there are no peer-reviewed data on these specific controls, testing by manufacturers and independent researchers (Gambatese, 2005) indicates that work zone lighting can be designed and used to provide optimal lighting. Safety and health experts believe that accidents can be significantly reduced through the proper use of work zone lighting. The extent of the reduction is dependent on the type of work being performed, the work zone area, the work conditions, and the equipment being used.
Daytime traffic flow is often disrupted by roadside construction work. To avoid day time traffic delays, new methods are being experimented with to improve lighting conditions of work zone environments at night. A new class of light towers, known as balloon lamps because of their appearance, is now being used in poorly lit work environments. While balloon lamps are comparable to traditional light towers in terms of wattage and light emission, balloon lamps are being increasingly used because they significantly reduce the amount of glare experienced by workers and motorist. Reduced glare creates safer conditions for both nighttime workers and motorists. Balloon lamps are also able to provide more evenly distributed lighting at work sites (Hassan, 2010).
Night work can create stress on the body, which interferes with the regulation of homeostasis. Well-lit working conditions have been shown to improve the health and well-being of nighttime workers. When bright light is used in work environments at night, the body’s clock more easily adapts to the time at which the work must be completed. Using bright light at night may also help with the prevention of seasonal affective disorders, which in turn helps decrease cases of depression in nighttime workers. Even brief exposures to light at night can help improve tolerance to night work, consequently improving working conditions and worker efficiency (Costa, 1993).
Nighttime roadside work is becoming increasingly popular as a way to limit daytime traffic congestion. An analysis of nighttime work environments shows that lighting conditions affected workers’ general perception of the area’s safety. Overall, the better the area is lit, the safer workers feel. The use of balloon lights in work areas provided the best lighting solution, leading to improved worker productivity and feelings of safety (Louis, 2013).
Baldor claims that their light tower will illuminate up to 7 acres.
The Sirocco balloon lamp is designed for nighttime work and provides 360 degree, non-glare illumination.
Effects on Productivity:
Work zone lighting helps to reduce the number of injuries and fatalities in poorly lit work environments. Avoiding injuries and fatalities reduces direct and indirect losses of work time. Conditions providing high illuminance show improved performance of cognitive work tasks. Workers who feel safe will, in return, perform more efficiently (Boyce, 1997).
Andrew Kingston and Michael R. Cooper - Aria Environmental, Inc.
Bruce Lippy - CPWR
Wanco Light Tower
To obtain information, visit Wanco, Inc. or contact 1-800-972-0755
Baldor Light Tower
To obtain information, visit Baldor Electric Company or contact 1-479-646-4711
NIOSH Workplace Solutions Sheet
The National Institute of Safety and Health (NIOSH) has published a series of “Workplace Solutions”, which are easy-to-understand recommendations from NIOSH research results. Related to this Construction Solution, please find more information on: Preventing Worker Injuries and Deaths from Backing Construction Vehicles and Equipment at Roadway Construction Worksites