Two varieties of such lamps exist.
Low pressure sodium lamp life.
It is mostly used in europe since it did not appeal in other markets due to its poor cri or color rendering.
The lps lamp was the first sodium lamp to be developed.
They also have the worst cri of any light source falling around a 25 and like metal halides require a warm up period and may flicker or cycle on and off at the end of life.
Sunlite 03610 su lu70 med high pressure sodium light bulb 70 watts ed17 med medium base e26 ansi code s55 6000 lumen 24000 life hours clear 2100k 4 3 out of 5 stars 277 13 46 13.
High pressure sodium lamps may be used in open luminaires except for item 67527 lu400t7 rsc and sox low pressure sodium which must be operated in an enclosed fixture.
Lamps are avail able from 35 to 150 watts in.
Like metal halides high pressure sodium lights are omnidirectional which wastes light and makes them less efficient.
A sodium vapor lamp is a gas discharge lamp that uses sodium in an excited state to produce light at a characteristic wavelength near 589 nm.
Lamps are distinguished by the use of the black bases compared to the tan bases used on sox lamps.
A low pressure sodium lamp is shown in the image below.
2 sodium retaining reservoirsprovide even distribution of sodium for 100 lumen maintenance long lamp life and lamp wattage control.
Even though they emit a yellow light a low pressure sodium lamp should not be confused with a standard high pressure sodium lamp which is a high.
3 u bend insulation featurecontrols lamp wattage rise and helps provide more consistent lamp life.
Standard lumalux standard lumalux lamps are known for high efficacy long life and reliability.
It is known by its signature monochromatic yellow color.
Sunlite 03610 su lu70 med high pressure sodium light bulb 70 watts ed17 med medium base e26 ansi code s55 6000 lumen 24000 life hours clear 2100k 4 3 out of 5 stars 283 13 46 13.
Low pressure and high pressure low pressure sodium lamps are highly efficient electrical light sources but their yellow light restricts applications to outdoor lighting such as street lamps where they are widely used.
Low pressure sodium lamps producing up to 180 lumens per watt have the highest efficacy of all commercially available lighting sources.
High pressure lights have a life expectancy of 16 000 to 24 000 hours while low pressure sodium lights should run for 12 000 to 18 000 hours.
A low pressure sodium vapor lamp or lpsv lamp is termed as a miscellaneous discharge lamp as it possesses some characteristics of high intensity discharge hid lamps as well as it resembles fluorescent lamps in other areas.