Sight Glass Lighting

What Is Sight Glass Lighting?

A sight glass is a window or transparent tube fitted to a pressure vessel, so you can observe what is happening inside. Sight glass lighting is a high-intensity light source installed outside of the vessel and above the sight glass for illumination. Because it’s installed outside the vessel, it prevents contamination or interference with the processes inside. It is also made to be corrosion-resistant, explosion-proof, and contain internal combustion.

Sight glass lighting is often used in hazardous environments with combustive elements, such as when mixing chemicals. This lighting makes it possible to monitor the process while sealing out materials from any potential ignition source in the light. By safely monitoring the procedure, you can prevent costly mistakes when mixing expensive applications, such as pharmaceuticals.

Papailias, Inc. carries a large selection of sight glass lighting options that offer highly effective illumination, even in hazardous environments.

Benefits of Sight Glass Lighting

Sight glass lighting uses high-intensity discharge (HID) lamps to create a light that is 22% more brilliant than a 100-watt light bulb. This powerful illumination shines deep inside a vessel for better visibility, allowing for a safer environment to clean between batches and prevent contamination.

This lighting is used in confined locations where there are substances, such as chemicals, gases, combustible fumes, fermented ingredients, dust, and debris, that could cause explosions. This seals the lighting elements from the environment to ensure the light will not be a potential ignition source.

Sight glass lighting is also non-invasive. They are mounted to the outside of the vessel to prevent contaminating the contents. This also makes them easy to access for cleaning. The fixtures are made from stainless steel and are manufactured without crevices or hard-to-reach corners that would make it difficult to thoroughly sanitize them.

These lights are designed to be environmentally friendly. The lamp has an extended life that lasts 35,000 hours, while halogen lights last between 1,000 and 2,000 hours. They use 93% less energy than a typical 100-watt halogen bulb.

Industries Served by Sight Glass Lighting

There are many industries that rely on sight glass lighting to provide safe, bright illumination:


In pharmaceutical manufacturing, proper lighting helps monitor precise formulations. Preventing contamination is vital when mixing pharmaceuticals to ensure the product is safe and effective. To maintain the right conditions, the lighting source must be mounted outside the mixing vessel and easy to sanitize.


Breweries must observe multiple processes in the production of beer. At the same time, they must keep out impurities; this ensures the product is untainted and fermentation isn’t altered by the addition of other microbes. For sanitary manufacturing environments, every piece of equipment must be easy to thoroughly sanitize. These fixtures must also provide excellent illumination into the process while resisting dust or fumes.


Bioenergy is another industry where you must be able to clearly see the processes as they happen, while also preventing any possible ignition source. As biomass is made into fuel, the steps must be closely observed. Explosion-proof sight glass lighting makes that possible while maintaining a safe work environment.

Other sectors that depend upon sight glass lighting include:

  • Agricultural
  • Chemical
  • Food and beverage
  • Military
  • Medical manufacturing

Papailias, Inc. and Sight Glass Lighting

Papailias provides sight glass lighting in a wide range of demanding environments. We have been in business since 1976 and deliver products from prototype to high volume production. Our fixtures are UL listed and meet ANSI, ASME, ASTM, and Mil-Spec standards, depending on needs. Listed for explosion-proof areas, Class 1, 2; Division 1, 2.

We are proud to offer the best in basic sight glasses, light/sight glass combinations, sight flow indicators, liquid level gauges, fused sight glasses, and specialized products to meet our customers’ unique needs.

Contact Us for Your Sight Glass Lighting Needs

At Papailias, Inc. our extensive expertise in the world of visual process control makes us the ideal source for your sight glass lighting needs. When you need an effective, sanitary, safe light source to illuminate manufacturing processes, contact our team to discuss your project. For more information on our many sight glass lighting solutions, use our convenient online request form to submit any questions.