The project is very similar to the project on high pressure mercury lamps. This had shown discrepancies between the participants and because of the commercial importance of sodium lamps it was considered important to verify that the luminous flux can be measured correctly.
Each participant was requested to carry out the measurements on four high pressure sodium lamps and four incandescent lamps.
A standard deviation of 0.64% was observed between eight of the laboratories involved. This result can be considered satisfactory in view of the poor stability and variations frequently found among production lamps. The work carried out should enable the other laboratories to identify errors in their measurements and correct them in the future.
Funding SchemeCSC - Cost-sharing contracts
TW11 0LW Teddington
W1R 9A London