History

Many people are unaware that the high pressure sodium bulb is one of the primary bulbs of the lighting industry. You may have unknowingly seen these bulbs in street lights, but they are also commonly used in industrial lighting, along with lighting design, and are a leading choice in indoor horticulture. These bulbs are especially favored by indoor growers because their light output is ideal for a plant’s flowering stage.

The high pressure sodium bulb has a long history, as it was first developed in 1920 by Arthur H. Compton who attempted to create a low pressure sodium bulb in the same form as an incandescent bulb shape (Whelan and DeLair 2013). However, due to both the extreme heat produced and the corrosive nature of sodium, the model did not succeed. Next, in 1931, Marcello Pirani of Germany created sodium resistant glass, an invention that led to commercial production of low pressure sodium bulbs (LPS) in 1932 by Phillips of Holland (ibid.). HPS bulbs were invented through research and development on ceramic glasses by General Electric scientists in 1955. Their invention was facilitated by the creation of Translucent Aluminum Oxide ceramic, or Lucalox, which is able to withstand high temperatures and pressure, as well as the  corrosion of the required chemicals. The HPS bulb was officially brought to market in 1964 (“Inventing Six Modern Electric Lamps”). 

Once available for purchase, local communities and planning boards especially shaped the use of the HPS bulbs through the citizens’ vocal dissatisfaction for other methods of street lighting. Gas lights were expensive and flammable, fluorescent bulbs were large, fragile, and produced weak light, and blue light-based bulbs made people appear to have an unhealthy pallor (“History of Street Lighting in the United States” 2018). The high pressure sodium bulbs represented an alternative lighting method, and became widely used in city planning around 1970, lighting up cities with its familiar yellow glow. 

When the HPS was first introduced, the main selling point was its brightness and efficiency. These bulbs have an average lifespan of 24,000 hours and are able to operate at 80–90% light emission output throughout their whole life. However, over the years, government regulations have encouraged competitors that are equally bright and require less energy. Despite the newly emerging competitors, the HPS bulb has remained a staple in the lighting industry, as the spectrum of sodium light is extremely difficult to reproduce. Since red light spectrum is important for a plants’ flowering stage, the HPS bulb became widely adopted by indoor home growers, and is an especially favored lighting choice in the cannabis growing community. 

From streetlights to cannabis, the HPS has had an interesting journey that is still far from over. Currently, scientists are using these bulbs to prove that plant life can be generated in unusual places such as Antarctica, the International Space Station, and maybe someday, on another planet.