|Application:||Street & Security Lighting|
|Diameter (max):||50mm (T-50)|
|Tube Length:||Approx 600mm|
|Bulb/Tube material:||Inner, glass, sodium resistant inner coating. Outer, glass, indium oxide IR reflective inner coating.|
|Colour Temperature:||1700K - CRI: Ra 0|
|Peak output wavelength:||589nM|
|Total light output:||7800 Lm|
|Rated lifetime:||15000 Hours|
|Operating voltage:||109V AC only|
|Warmup/restrike time:||15 Minutes/Instant|
|Cost (original):||Not known|
|Value (at time of writing):||£32.00 from BLT Direct as of Q2 2009|
|Place of manufacture:||Great Britain|
|Date of manufacture:||Not known - Date code N418 shown on lamp|
|Lamp Status:||Working, new.|
Once a mainstay of the street lighting industry in both mainland Europe and the UK, low pressure sodium lamps have started to become an increasingly rare sight since around 2015 when the general trend has been to move towards white overnight lighting for outdoor spaces. Especially since around 2020 when the use of LED technology in this field has exploded with its (sadly often exaggerated) claims of higher efficiencies and maintenance-free fixtures.
The late 90s and early 2000s probably represents the heyday of SOX lamp design, where the design and construction process had been sufficiently refined to such an extent that the lamps were supremely reliable.
This lamp is believed to date from just this side of the year 2000, based on it appearing to be of Philips construction which points towards it having been made after the closure of Osram's Shaw factory in 2000, after which they sourced their low pressure sodium lamps from Philips.
It really is quite astonishing in a domestic setting how much light one of these things gives off for its 55W power rating.
Osram SOX/H 55W Low Pressure Sodium Lamp - General overview.
Osram SOX/H 55W Low Pressure Sodium Lamp - Detail of lamp cap
Osram SOX/H 55W Low Pressure Sodium Lamp - Detail of lamp cathodes
Osram SOX/H 55W Low Pressure Sodium Lamp illuminating my workstation (with eye-searing intensity) from a distance of approximately two metres
Osram SOX/H 55W Low Pressure Sodium Lamp - Shown while alight
Osram SOX/H 55W Low Pressure Sodium Lamp - Showing size of lamp
Osram SOX/H 55W Low Pressure Sodium Lamp Output Spectra
Osram SOX/H 55W Low Pressure Sodium Lamp - Detail of text printed on lamp
Osram SOX/H 55W Low Pressure Sodium Lamp - Shown when first powered on, with the discharge being entirely carried by the Neon/Argon gas fill until the lamp starts to heat up and the sodium vapour starts to rise.
Osram SOX/H 55W Low Pressure Sodium Lamp - After a few minutes operation the sodium vapour starts to take over the discharge and the characteristic monochromatic amber colour begins to appear
Osram SOX/H 55W Low Pressure Sodium Lamp - Close up of the arc tube U-bend showing sodium retention ridge and heat reflective disc which also provides mechanical support for the arc tube
This lamp added to the Virtual Display Shelf on the 23rd February 2006 at 22:35.
Acknowledgements: Many thanks to the website reader who traded this and a number of other lamps for display here.
This page last updated:
19th June 2023: Changes to page formatting to improve readability on mobile devices, also made some background page code changes to improve search engine behaviour.