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RE: Preventive Maintenance For Lamps

Jeri Knaus from the Illinois Waste Management and Research Center contributes the following on this topic:

In response to Judy Kennedy's question regarding Lighting

I just read "Lighting Upgrades - A guide for Facility Managers" second
edition, written by Damon Wood, CLEP, LC. Mr. Wood was previously
responsible for the EPA Green Lights program. There is an entire
chapter devoted to lighting maintenance, some very technical, including
calculating lamp lumen depreciation and luminaire dirt depreciation
creating the light loss factor. He also talks about saving money
through improved maintenance.

Here are a couple of excepts from the chapter that might be helpful:

"...group maintenance...labor costs associated with fixture relamping
and cleaning can be cut by over 70 percent; expense of lamp purchases
can be reduced through fewer, higher volume transactions. ...improved
maintenance practices...more lighting value per dollar expended."

"Many maintenance managers are hesitant to replace lamps that are still
operating. But after comparing the average annual cost of sporadic spot
maintenance to that of group maintenance (i.e. relamping/cleaning) many
have decided to switch to a group maintenance strategy."

"To determine the optimal time to group relamp, refer to the lamp's
mortality curve (there is a table in the book) which represents the
cumulative percentage of lamp failures that occur over time. ...the
rate of fluorescent lamp failures becomes significant at approximately
70 percent of rated life, HID relamping intervals are typically
scheduled between 60 and 70 percent of rated lamp life, depending on the
cost of spot-relamping failures that inevitably occur before group
relamping is performed."

Hope this is helpful. This book can be found at
http://www.fairmontpress.com/store/detail.cfm?id=188&itemid=844 and at

At 12:53 PM 8/30/2004, Illig, Richard wrote:
The concept of changing out all lamps at the same time can be economical pending actual circumstances.  Some items to consider are:
      Nearly all lamps have a loss of output over time.  The largest drop in output typically occurs during the last few thousand hours of lamp life.  If all lamps were installed at the same time, the thinking is that once several lamps burnout that the rest of the lamps are already functioning at or near reduced output levels and are also due to be changed.  Inexpensive lamps – like fluorescent – help make this case.
      If your staff needs to rent a lift to access lamps in high-bay areas, rent may be reduced doing all lamps rather than renting a unit several times yearly.
      Maintenance costs can be a large part of lamp replacement.  If you consider hauling a ladder out every time a few lamps burnout the time and effort adds up.  It can simply be more efficient labor-wise.  One LARGE benefit of LED or induction lighting is the exceptionally long life – 25+ years and ~10 years, respectively - and reduced maintenance costs.
      If your business has scheduled shut-downs for maintenance, it may be easier to change out all lamps at that time rather than when actively producing.  Food processing operations or anyone operating 24/7 might be an example where added care may be needed changing out lamps.  Commercial operations may be another example of where public perception makes it more appealing to get the job done rather than have a ceiling dotted with burnt out lamps.  Remember, although the lamp is burned-out the ballast continues to operate.  Like idling your car engine…zero miles per gallon.
Unfortunately, I have no case studies on the topic.  Check with a lighting professional.  A good one should be able to paint a much clearer picture.  Ric
-----Original Message-----
From: owner-p2tech@great-lakes.net [mailto:owner-p2tech@great-lakes.net]On Behalf Of Kennedy, Judith C.
Sent: Monday, August 30, 2004 12:34 PM
To: 'P2tech@great-lakes.net'
Subject: Preventive Maintenance For Lamps
Can anyone provide me with some information on preventive maintenance programs for commercial/industrial lighting, where all lamps are periodically changed at the same time, whether they need it or not?  This is supposed to save much money.  How does one determine the frequency of change-out?  How does one estimate the potential savings?  Are there any good case studies out there?  I would appreciate any information or leads you might have.

Judy Kennedy
Hazardous Waste and Toxics Reduction Program
Washington State Department of Ecology
P.O.Box 47775
Olympia, WA  98504-7775
Phone (360) 407-6385
Fax  (360) 407-6305
Email:  jken461@ecy.wa.gov