LAMP LIFE PERFORMANCE OF HIGH-PRESSURE SODIUM LAMPS IN THE CITY OF LONDON

The City of London Corporation pioneered the widespread use of high-pressure sodium lamps for public lighting in 1967, through a programme for changing overall lighting on main traffic routes in the city. The programme was completed in 1972 and by March 31, 1976 the city had 1573 - 400 watt son/t lamps in use on 12 miles of classified roads. Reports published in 1968, 1969 and 1973 indicated that lamp-makers original estimates of a 2000 hour average rated life were being exceeded, and questioned whether bulk changing was justifiable bearing in mind the long life, low premature failure rate, maintained efficiency and colour quality, and high cost of the lamp. In this report the lamp life performance of an installation of 653 - 400 watt son/t lamps used in the city is discussed. The author explains that some of these lamps have now completed 30000 hours, which is equivalent to over 7 years in use as sunset-to-sunrise public lighting. Figures quoted are used to indicate that luminous efficiency continues to improve, from 90 lumen/lamp-watt quoted in 1966 to 120 lumen/lamp-watt today. /TRRL/

  • Availability:
  • Corporate Authors:

    Printerhall Limited

    29 Newmart Street
    London W1P 3PE,   England 
  • Authors:
    • Austin, B R
  • Publication Date: 1976-8-9

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Filing Info

  • Accession Number: 00145363
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS
  • Created Date: Apr 13 1977 12:00AM