Adequate lighting on construction sites guarantees staff's safety and health, enables workers to detect and avoid hazards more easily and quickly, increases productivity and efficiency, prevents unwanted visitors or trespassers, and helps deliver high-quality work.
In addition, it can be employed to carry out works at night, especially when daylight is not enough to complete the work or when construction activities are required to be done at night, such as concreting, because of high ambient temperature.
Site lighting could be used internally for lighting up construction sites to carry out a specific task or for general walking and externally for storage areas. The provision of sufficient lighting is generally the responsibility of a contractor.
Why is Adequate Lighting Critical for Night Construction?
- Proper light is essential for labor safety, productivity, and to ensure the quality of the work.
- Construction sites develop continuously. Hence, sufficient lighting is critical for emergency evacuation situations as construction sites do not have permanent escape routes.
- Construction materials and portable equipment are moved from one place to another throughout the project lifecycle. Therefore, the risk of injuries is always present during the evacuation process unless adequate lighting is installed.
- Sufficient lighting will help complete the work within a specified deadline.
- Specific works like unloading construction materials and executing construction tasks such as concreting can be carried out at night. However, concreting at night is sometimes necessary due to hot weather conditions.
- Proper lighting is vital for the safe movement of vehicles within a construction site. In addition, it decreases or eliminates vehicular collisions and pedestrian falls.
How to Plan Construction Site Lighting?
Spending a few hours on planning the arrangement of lights can save many hours, prevent workers from waiting to move, decrease auxiliary lighting during works on construction sites, and improve productivity.
Lighting is not fixed throughout the construction process, so a proper plan should be established to relocate lighting equipment at different construction stages. The effects of illumination on surrounding occupants and wildlife need to be taken into consideration. It should not change the apparent color or safety signs.
Planning could be carried out by drawing a scaled layout of the construction site and determining types of works, location of equipment, and workers to install adequate lighting and ensure the power supply.
Finally, assess lighting value measured by the amount of light per square foot (foot-candle) or lux (lx) in the metric system.
According to the American Traffic Safety Services Association (ATSSA), a foot-candle definition is a unit of illumination equal to one lumen per square foot (1 foot-candle = 10.764 lux). Minimum targeted values for buildings are recommended, which are shown in Table 1:
Table-1: Recommended Minimum Targeted Value for Lighting
|Type of lighting||Activities||Recommended Minimum target values (lux)|
|General working areas||15|
|Carpentry and joinery||100|
|Painting and decorating||200|
|Drawing board positions||300|
1 foot-candle = 10.764 lux
Unusual conditions, dirt, and deteriorations are not taken into consideration in Table 1. So, twice the minimum recommended targeted values could be used to design lighting. Moreover, suitable arrangements of illumination for any situation are provided by manufacturers, but the following equations will find lamp requirements:
The utilization factor is equal to 0.23, but for dispersive light, 0.27 should be used.
After determining the lamp type to be employed, the number of the required lamp can be computed:
Arrangement of Typical Site Lighting
The following figures explain a specific lighting area.
Minimum heights for tungsten halogen lamps are as follows:
- 7.5 meters for 500 watts
- 9.0 meters for 1000 watts
- 15 meters for 2000 watts
Minimum heights for dispersive lamps are as follows:
- 2.5 meters for 40 to 125 watts, fluorescent
- 3.0 meters for 300 watts, tungsten filament
Local and Walkway Lighting
Festoon or bulkhead lighting can be used separately or with each other to illuminate routes and general circulation on a standard main voltage of 230 V or on reduced voltages of 110 V. To avoid unacceptable shadow and provide maximum possible lighting at the workplace, lamp fittings on strands or hand lamps with trailing leads can be employed. Figure-6 shows walkway and lighting fittings.
Figure-6: Bulkhead Lamp (left side), Light and Stand (right side)
Construction site lighting is a system of temporary lighting installed to help improve the effectiveness of workers and prevent accidents and injuries during construction at night.
Proper construction site lighting is critical for laborers to work effectively and safely. It decreases or eliminates the risk of injuries and illuminates walking and escape lines.
1 foot-candle = 10.764 lux