Seeing the Light

Sep 1, 2007 12:00 PM, By Gary Nangle, P.E., Cronis, Liston, Nangle & White, LLP

Industrial buildings follow the lead of other sectors when it comes to lighting trends

Although industrial lighting has historically been a step behind technologies used for other building types, many of the advancements made over the past decade in lighting for other occupancies are finally taking hold in industrial spaces. It's only a matter of time before task-oriented lighting, energy-efficient alternatives, and bi-level lighting designs are installed regularly in industrial buildings across the United States.

Task lighting

Industrial lighting is following the trend in other sectors where “light the task” has become the popular mantra. While lighting designs for office spaces no longer light the top of the file cabinet and bookcase along with the desktop, warehouse lighting is no longer just concerned about horizontal footcandles to avoid forklift collisions. Vertical footcandles on the stored materials are also an important element of the design criteria. In addition, industrial spaces are no longer hanging 400W high-intensity discharge (HID) high-bay fixtures on 25-foot centers from wall-to-wall.

Low light levels at workstations, such as this inspection station, can lead to eyestrain and fatigue. One solution is a simple strip fixture over the inspection station with a local switch to boost light levels only where and when needed.

As “lighting the task” tends to reduce lighting levels overall, the levels of lighting for portions of industrial spaces need to increase. For example, raw material and finished goods staging areas may need only 30 footcandles for safe operation, while final inspection areas require more than 80 footcandles. However, a compromise of 50 footcandles everywhere is not the solution. Nevertheless, reasonable uniformity is necessary to reduce adaptation discomfort when processes require workers to look from one light level to another.

Proper lighting levels in industrial occupancies also have the highest relation to safety and lost time reduction when compared to just about any other occupancy. Low light levels at workstations, such as inspection stations, can lead to eyestrain and fatigue.

One solution is a simple strip fixture over the inspection station with a local switch to boost light levels only where and when it's needed (Photo). Improving on this simple approach, you can also install an occupancy sensor at the station for automated control. In fact, some may argue that task lighting was invented for industrial applications — the task light on the band saw was probably in service long before the task lights in office cubicles.

Bi-level lighting

While not new, bi-level lighting can also be an effective industrial lighting design tool. Optical storage systems “pickers” and robotic systems need little, if any, light to perform their task. People, on the other hand, need lighting to perform maintenance and make inevitable repairs on equipment.

Bi-level lighting systems have long been in use in warehouse aisles. With the insignificant cost of occupancy sensors, the time has come to control lighting in more areas by occupancy. This technology should not scare facility managers — the horror stories associated with occupancy sensors can almost always be attributed to improper sensor application or adjustment.