Letters
Crucial maintenance
I would like to contribute a few comments on your article entitled "60 000 Hours of No Maintenance" about Philips' "QL" lamp (issue 1/92). Of course, long lamp life (accompanied by acceptable lumen depreciation characteristics) is a good thing, and 60 000 hours is a breakthrough, but maintenance is a larger and more complex issue that includes factors such as dirt depreciation and moisture damage.As an illustration of the importance of maintenance, in my country it is estimated that the equivalent of 175 000 full-time jobs are required for cleaning lighting fixtures, changing lamps, and other types of maintenance. Thus, long life and low maintenance are best pursued through considering the design of the entire luminaire, including, but not limited to, the lamp alone. Various ideas are under consideration within the Russian lighting research community, and we welcome the interest of other scientists and entrepreneurs.
Julian Aizenberg
All-Union Russian Lighting
Institute, Moscow, Russia