Lamp Seasoning
by Edward Bartholomew IALD, IESNA, LEED® AP

Distaste for Unseasoned Lamps - Should fluorescent lamps be burned in before being installed in dimming systems?

Currently there are many conflicting recommendations on dimming fluorescent lamps and whether they need to be “seasoned” prior to installation. Seasoning is a method of burning-in new fluorescent lamps for a specified amount of time to ensure optimal lamp performance and life. New fluorescent lamps go through a stabilization process that allows particulates to burn off while evenly distributing mercury in the tube.

Seasoning fluorescent lamps is primarily related to two issues; the first is that the light output of a fluorescent lamp changes during the first hours of operation. The second issue is that all of the published fluorescent lamp ratings by all lamp manufacturers are based on tests using pre-seasoned lamps. These lamps have to be burned-in for 100 hours per IESNA LM-54-99. The differential between seasoned and non-seasoned lamps regarding lumen output, lamp life and system wattage is yet to be determined, but you may not be getting the amount of illumination that you have calculated for, based on whether the lamps were seasoned or not. This gets even more complicated when we factor in fluorescent dimming systems.

The Lighting Research Center in a report on Reducing Barriers to Use of High Efficiency Lighting Systems states that, “Manufacturers have discussed new requirements for lamp seasoning..., but consensus standards can not be obtained because the operating characteristics of fluorescent dimming systems are not defined.” Basically, fluorescent lamps were not made for dimming, and there is no standard method for dimming them. The failure of fluorescent lamps in dimming systems would appear as “banding” or blackened ends and even premature lamp failure. When specifying fluorescent dimming systems designers and engineers should inform end-users and facility managers about the issue of lamp seasoning. Confusion around this issue has already lead some hospital facilities managers to install racks of “lamp seasoning” stations in there storage areas, while others have decided to forgo installing fluorescent dimming systems altogether.

Recently several manufacturers have discontinued the warranty on T5 lamps for dimming systems. Yet a majority of users simply have no procedure for seasoning fluorescent lamps, with or without dimming systems. Lighting system commissioning that uses daylight sensors along with fluorescent dimming should especially be advised to factor in lamp seasoning into their maintenance procedures. Finally with the promotion of environmentally friendly low-mercury fluorescent lamps, the problem of premature lamp failure caused by non-seasoned lamps may be further exasperated. We have assembled a table showing various organizations and manufacturers and their position on this knotty issue.

We have assembled a simple table showing various organizations and manufacturers and there position on this convoluted issue.