June 02, 13
Warehouse Lighting: Logistics & Solutions
- Warehouse Lighting: Logistics & Solutions
There are a variety of choices for warehouse lighting but a number of criteria should be examined before selecting a lighting technology. The area required to be illuminated, the height of the luminaires, the amount of traffic in the area, the type of work done and the ambient air temperature are all practical aspects to be considered. Forward thinking companies are also concerned with carbon emissions and sustainability issues, particularly in large-scale applications.
Technologies to be dismissed out of hand are mercury vapor, low pressure sodium (LPS), high pressure sodium (HPS) and incandescent lighting. These obsolete systems suffer either from limited emission line spectrum, a relatively short lamp lifespan, ultraviolet hazards or lumen depreciation. All are energy inefficient compared to newer systems.
Beginning in the 1960s high intensity discharge (HID) lighting came into use. The most popular type is metal halide (MH) because of a high luminous efficacy (twice that of mercury vapor and three to five times that of incandescent) and an intense white light. With their wide spectrum, they offer good color rendition but suffer from slow warm up times and a limited restrike capability. Like earlier technologies they have the drawbacks of lumen depreciation and potential exposure to dangerous UV rays. One safety concern, although rare, is the risk of lamp explosion – invariably a violent occurrence. A recent development in MH technology is the introduction of pulse start metal halide lamps, characterized by better energy efficiency (15%), higher lumen maintenance, better color rendition and a faster restrike capability compared to older MH systems.
In the search for cost savings, better performance and higher energy efficiency over existing technologies, manufacturers have evolved fluorescent lighting systems to include outdoor, high bay and warehouse applications.
According to Philips Lighting, 65% of all energy consumed in the U.S. is by commercial and industrial markets – 22% of this energy is being utilized by lighting alone. These statistics indicate that there are substantial savings to be achieved by replacing HID lighting systems with more efficient fluorescent technologies. Fluorescent T-5 high output (HO) lighting offers up to 50% in energy savings over HID with functionality advantages of high color rendition, illumination uniformity and rapid-start cycling. Even greater savings are realized when occupancy sensors are used in low traffic or intermittently occupied areas, a feature not available in HID systems. And using new amalgam technology, so-called T-5 “very high output” (VHO) lamps are designed to perform in extreme temperature environments, overcoming the light emission limitations of earlier T-5 lighting systems.
A part of the new T-5 fluorescent technology that is often overlooked is the development of higher efficacy fixtures or luminaires. Typically MH light fixtures have low efficiencies of 75% while T-5 HO luminaires boast of efficiencies as high as 92%. And as a matter of aesthetics, environmental health and productivity, it is not optimal to just see objects but see them sharply enunciated.
A Philips Lighting customer sums it up: “Lighting a warehouse is a complex exercise. Large spaces to be covered, costs/carbon emissions to be considered, yet adequate illumination is required at all times.” Careful planning can be rewarded with a cost-effective, productive workplace for years to come.