At first glance, it may seem economical to run lamps to failure. Why discard lamps that still have 10% life left?
Actually, there’s a good reason to discard lamps that are approaching end of life. It’s called “poor lighting.” Lamp specification documents typically contain a graph showing light output vs. lamp life. There’s a fairly flat line that suddenly curves downward. You want to replace the lamps before they hit that curve.
If you were determined to run every lamp to failure, you could greatly overlamp each area and use a control system to maintain lumen output. But this poses several cost and technical problems that preclude it from being practical.
Two other approaches help stretch your lamp dollars:
- Scheduled spot relamping.
- Scheduled group relamping.
Ideally, you would do only group relamping. Realistically, you’ll do some spot relamping, even if you have a solid group relamping program. But spot relamping should be in response to damage (e.g., from power spike), rather than routine.
For scheduled spot relamping, set up a Preventive Maintenance (PM) task in your Computerized Maintenance Management System (CMMS). The PM is a walk-through to note where lamps are burned out. The next step is to enter a work order in the CMMS for replacing all lamps in a given fixture.
This is more economical than having techs running around replacing one lamp at a time. But it can be five times more expensive than group relamping. Do it as repair, not maintenance.