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By Thomas A. Westerkamp
December 2007 -
Energy Efficiency Article Use Policy
Most institutional and commercial facilities rely on quality lighting to keep occupants comfortable and operations efficient. But problems can arise when lighting-system components start to lose their effectiveness.
Maintenance and engineering managers can reduce the loss of lighting effectiveness with a well-organized preventive maintenance program. One of the most important decisions managers face is determining the scope and content of their organizations’ lighting maintenance program and, in particular, its relamping activities.
One option managers have is to set up routes throughout facilities and assign a technician to replace burned out bulbs at regular intervals so light levels don’t drop before the end of lamp life. Among the problems with this process is it involves a great deal of travel time and can be very costly, since no one knows exactly when a lamp will burn out.
A second option is planned group relamping — replacing all lamps in an area when, say, the average lamp reaches 70 percent of its performance life. Proponents of group relamping point out that it might cost as much as 10 times more to replace lamps one at a time than in groups.
The strategy of group relamping increases material costs because the process often involves replacing lamps when they are still bright and burning. But this factor is only part of the total cost of relamping. Labor is the other major cost.
Since workers change all lamps in an area at one time, they can clean and, if needed, reballast during lamp replacement, saving a great deal of time setting up, bringing materials to and from the job, and handling ladders and scaffolding.
Managers also can consider contract relamping using specialized equipment and labor. Because contractors offer specialized skills and take on labor and inventory responsibilities, this strategy can reduce the organization’s overall labor cost, even though a contractor’s hourly rate is higher than the in-house rate.
Group relamping offers other advantages besides lower labor costs. Lamp-storage costs also are lower because lamps are not part of the in-house inventory. Managers know in advance when an area will be relamped and can order lamps to arrive just in time, reducing inventory costs.
This method also keeps lighting levels closer to required levels, which promotes higher productivity and lowers fatigue due to stress. And since a sharp drop in lumen output occurs after lamps reach 70 percent of average life, managers also can operate in a more cost-efficient range where the cost per lumen is optimum.
After lamps reach the 70 percent level, the energy cost remains the same, but the lumens produced decline. When lighting-system designers know that spot relamping — not group relamping — is likely going to take place, they specify more fixtures because they know the maintenance factor will be lower under less-well-maintained conditions. This design decision drives up installation costs.
Another benefit of group relamping is managers can schedule it for off-hours, when the activity is least likely to disrupt normal facility operations.
Here is one final piece of evidence in favor of group relamping: A recent computer analysis of lighting-maintenance strategies compared group relamping, coupled with fixture cleaning every three years, to spot lamp replacement and no cleaning. The area in question was 10,000 square feet, and operations were conducted on two shifts of 4,000 hours per year. The relative cost to maintain the same footcandle lighting level with group relamping was only 79 percent of the cost of spot relamping.
Relamping is a special category of electrical work, often used as a starting point for on-the-job training of electrician apprentices or those seeking an apprentice training program as a career path. Depending on the size of the facility and complexity of the lighting system, the position might be full-time for one or more relampers.
Technicians must gain a basic understanding of electricity before actually working on power-distribution systems. Relampers must know the different lamps and their applications, and they must be able to keep track of lamp inventory and use rates. They also prepare requisitions to replace lamp supplies for approval by supervisors. They also need to keep lamp carts full of the necessary assortment of lamps and tools for building and outside area lamping.
Technicians also are required to lift heavy fixtures, climb ladders and work on scaffolds and structural steel when required.
Relamping technicians use hand and power tools, testers, and instruments, and they operate lift trucks and cleaning equipment. Major duties include replacing lamps according to scheduled work requirements. The duties also involve visual and operational checks of fuses, breakers, switches and ballasts. Associated duties include cleaning fixtures, moving equipment for access, and disposing of damaged or used equipment.
Sometimes, the scheduled route is interrupted by calls to replace burned out bulbs or flickering problems. When this happens, the relamper has to leave the assigned area and travel to a distant location, then climb to a ceiling location to replace a single bulb.
The more managers can keep the relamper on scheduled assignments and away from trouble calls by using a planned and preventive maintenance approach, the lower the total cost of group relamping will be.
Managers seeking to justify expenditures for lighting equipment to higher management can point to the benefits of good lighting. The benefits include:
— Thomas A. Westerkamp