Factors to Consider When Selecting Lighting for the Jobsite
Since every project is different, it’s important to consider lighting for each jobsite prior to beginning work. There are a lot of factors that affect what you need, such as the time of year, the time of day, the terrain, the conditions (inside or outside), power source, types of bulbs, and any restrictions to the area (such as sound).
We strongly encourage that you begin your lighting plan while you take all of these jobsite aspects into consideration. With so much to consider, we encourage you to create and document your jobsite lighting plan.
The power source you use will be one of the most important early factors to consider because it will affect what lights you use. For now, we’ll focus on the power source, but keep in mind that some power sources may not be viable options, so it is probably a good idea to consider an alternative power source when there are restrictions or other factors that could eliminate a particular lighting source.
Selecting a Power Source and the Importance of Run Time
There are generally three primary power sources:
1. Diesel engines
2. Electric and electric hybrids
3. Battery power
Most traditional light towers are powered by diesel engines since they are often used in more remote areas or locations where other power sources either aren’t practical or reliable enough. For example, nighttime construction on a highway will be too far from most electrical sources.
Energy efficient bulbs are a great choice, especially when using diesel for power because lower energy consumption saves refueling time. Fuel is often a large expense on a project and constantly refueling can cause interruptions. Lower fuel consumption also helps to reduce the environmental footprint for the project. You should also consider the fuel capacity, especially for remote sites where it is more time consuming to refuel the engines.
Apart from the noise, one of the biggest problems with lights powered by diesel engines is the fact that the fuel could spill, resulting in fines. If you must use a diesel engine to light your site, make sure that the tower has preventative measures to significantly reduce the risk of spills.
An electrical source will generally be the best option because you won’t have to worry about work interruptions related to your power source. When possible, it is strongly recommended to use electric-only light towers because they can be easily connected to their power source. Technology has made it possible to daisy-chain your electric towers, which increases lighting efficiency and lowers the overall cost. In addition to being better for the budget, they are more environmentally friendly and are considerably quieter.
Another recent development in lighting technology is the electric hybrid option, which uses solar energy to help further reduce the carbon footprint and the cost of operating a jobsite light. However, they are not ideal for many construction conditions as the panels can be easily damaged.
Given the restrictions of both of these power sources, some manufacturers have developed robust tower lights that are battery-powered. These systems are designed to be just as portable as traditional lighting sources and use LED light heads to provide a greater illumination area than is typically associated with battery-powered options. One consideration when using battery-operated lights is run time (some systems can operate up to 10 hours on a charge). Just like using power tools on a battery platform, it’s always a good idea to have a good charging station with a few extra batteries on deck.
LED vs. Metal-Halide
There are two primary types of lights: LED and metal-halide.
LEDs are a product of more recent technology, and they have a lot of benefits that traditional metal-halide lights don’t offer. Perhaps the most well-known benefit is that they are not made with filaments that will burn out. They also use lower wattage, making them more energy efficient. They provide a clearer, cleaner light for the immediate area being illuminated (though they don’t provide much light for the surrounding area). They don’t require being warmed before use or cooled after use. LED lights can last up to 50,000 hours.
While there are a lot of benefits to LED lights, metal-halides have been used in the industry for more than four decades. Because of this, most light towers use metal-halide lights since they are known for their reliability. They are both cost effective and incredibly efficient in illuminating larger areas, lighting both the immediate work area as well as the area beyond the work zone. Their lifespan is estimated to be about 10,000 hours per light bulb.
Lighting Color TemperatureLights come in a range of colors, which often denotes both how much light is perceived, as well as its color (or temperature). Lighting color/temperature is often described using the Kelvin (k) scale. Lower Kelvin temperatures are warmer colors and higher temperatures are cooler. For example, moonlight is about 15,000˚k, while the light in the morning of a clear day is about 5000˚k. Fire has the lowest Kelvin temperature, which means it is the warmest at about 1900˚k. The color temperatures that are perceived as the “brightest” by the human eye are in the 5000˚ – 6000˚k range.
Metal-halide bulbs do not maintain a consistent Kelvin color temperature because the light degrades as the filament burns out. LEDs offer a more consistent light and have a higher (cooler) Kelvin color temperature.
Lighting is also measured on a Color Rendering Index. This indicates the source’s ability to show colors more accurately, which is important when a jobsite has warning labels and hazards that need to be visible all of the time.
IP Rating for Dust/Rain
Things like rain, dirt, dust, and particles are a given when it comes to jobsites. To see if your lights will be able to withstand the elements and debris, you’ll need to check the Ingress Protection (IP) rating. This rating indicates how protected the lighting is.
• The first number of the IP rating indicates how dust resistant a light is. The higher the rating, the better the protection against increasingly smaller particles. The highest rating is 6 and it is considered dust tight. This rating is only given to lights that are able to run through an 8-hour test without any dust getting into the light.
• The second number of the IP rating indicates how water resistant a light is. The highest ranking is 9.
It’s important to consider the amount of sound that lights make, considering how loud some lighting systems can be. When a jobsite is near a residential area, there will almost certainly be applicable noise regulations that you will need to comply with.
Sound is measured in decibels (dBA), with the boundary for safety being 85 dBA. This is the noise level at which you are more likely to need to raise your voice when talking to someone standing directly next to you. At this point, workers should be using ear protection.
Depending on the source, some lights can actually make a considerable amount of noise, contributing to the overall site noise level. For jobsites with stricter sound restrictions, you will need to find lighting sources that contribute little to no noise. There are some lights that operate in silence, even lighting towers.
Proper PositioningThe terrain plays an important role in where to place light towers. You want to find the flattest, firmest possible surface so that the lighting tower will be stable while in use. Towers can fall if they are set on uneven ground or on sandy surfaces.
Pay attention to potential obstructions, such as trees and power lines, so that you don’t damage the tower or endanger the workers. Be aware of the height of the light so that you can ensure it is deployed in a location that is free of potential obstacles.
Prepare to test the lighting to ensure that the tower is positioned to provide direct light in the best places. You don’t want light generated from fixtures to obstruct the visibility of drivers if the construction is near a road. Position the light so that it faces away from oncoming traffic. You also want to minimize the amount of light that affects any nearby residences.
For some jobs, you don’t need to provide high levels of illumination because the accuracy of the work isn’t as critical. Illumination can be divided into three levels to help you better determine what kind of lighting you need for different areas of your jobsite. As you develop your lighting plan, consider these factors:
Amount of Illumination Needed
• Level 1 (54 lumens) is adequate when low accuracy is required for tasks. It is most often used for flagger stations and lane and road closures.
• Level 2 (108 lumens) is adequate to help workers complete moderate levels of accuracy. This level is often adequate for places where construction equipment moves around, and workers are doing things like paving and concrete work.
• Level 3 (215 lumens) is for areas where work needs to be very accurate, such as filling potholes, repairing pavement and joints, and installing equipment.
ApplicationThe final factor to consider is probably the most obvious – the application of the lighting. Will the work be done indoors or outdoors? What kind of construction is it (industrial, commercial, event preparation, roadway, or something else)? What time of day or night will workers be active? Will the work be done in a remote location?
If the work will be completed indoors, you will need a different type of lighting equipment than outdoor work on a roadway. Work being done in a commercial area will require a very different kind of lighting than a residential area or along a road.
Probably one of the most significant applications for lighting considerations is if it will be done at night. Workers need adequate lighting to be effective, but it shouldn’t disrupt oncoming traffic or nearby property owners. If the work zone is stationary, luminaries may be mounted on poles. For more mobile work, light towers mounted to a highway-safe trailer can be repositioned as the work activity moves. If you’re on a US Department of Transportation project, there may also be state specifications for lighting compliance to consider.
All of these factors should be considered when creating your construction lighting plan.