Lighting requirements in explosion-proof environments are defined by the Occupational Safety and Health Administration (OSHA). This type of lighting is required for hazardous locations. This includes:

  • Areas that contain flammable vapors, liquids, or gases
  • Areas that contain combustible dust or fibers

We wouldn’t be very surprised to know that you never thought about the factors like personal and property security while purchasing lighting solutions for your commercial or industrial facility. However, take our word of caution here.

As the owner of a facility, you must know the potential hazards related to lighting that can occur with using the wrong type of light. Many hazardous places in the US need to use Hazardous Location lighting.

explosion proof lighting

Why is LED a Must for Hazardous Locations?

Hazardous Location Risk Factors

As the manager or owner of any facility where activities in hazardous environments are performed every day, you must know that you are putting everyone working in your facility at risk by not having the right hazard-safe lighting installed on the premises.

If you use the wrong lights that do not comply with the classification standards of hazardous locations, then you could be charged in violation of the regulatory standards of OSHA, NFPA, and NEC/CEC. Even small-scale accidents can result in large penalties.

How Do Locations Identify as Being Hazardous?

Determing a hazardous location depends on many of factors. You can identify a location as hazardous based on whether a particular type or amount of fuel is stored, or explosive dust is present.

Presence of Flammable Liquids and Gases

Wherever flammable gases and liquids are present, the location may be identified as a hazardous one because such compounds can cause an explosion or catch fire.

Gas and liquids must achieve a critical concentration before it becomes dangerous. However, once they do, that’s when a potential disaster can occur.

Many other flammable gases can cause this like ethylene, hydrogen, ammonia, methane, butane, carbon monoxide, propane, acetylene, and many others.

Presence of Air-Suspended Combustibles, Fibers / Dust

Have you ever thought about dust being dangerous? Well, if not then you should know that there are many flying fibers including dust that can turn out to be hazardous.

Dust can be harmful in two ways.

  • Formation of an explosive cloud by mixing with air and overheating electrical components by accumulating on their surface and insulating their heat.
  • In wall, electrical fires can be caused by dust fibers.

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Four Industrial Sectors That May Generate Harmful Explosive / Combustible Dust

  • Agricultural products including spices, grass, cotton, coffee, grains, dust, flour, wood flour, sugars, starches, powdered milk, egg white, and other agricultural dust
  • Industrial products that form carbonaceous clouds including cellulose, cork, petroleum coke, charcoal, coal
  • Chemical products including sulfur, lactose, methyl-cellulose, and metal dust including zinc, magnesium, aluminum
  • Different plastic products including vinyl varieties, melamine

Methods of Stopping Ignition

Even though dust, liquids, and gases differ a lot from each other in almost all aspects, the one thing that they have in common is their trigger point or ignition. If they don’t ignite, there is no issue. So, how does ignition occur?

The ways fuel ignites is – the fuel is in an explosive state and is exposed to an ignition source like an open flame, spark, and air in combination or the fuel reaching its Auto Ignition temperature (AIT).

AIT is the point when fuel ignites in the absence of any external ignition source. AIT scores are used by safety organizations to decide the maximum operating temperature standards for heat-emitting devices like heavy machines, etc.

HAZLOC safe LED lights are built as per the safety standards to contain flames or sparks during any general or emergency operating situation. These lights are also built according to the maximum operating temperature standards that are set to match the individual settings of the lights. The reason why LEDs are best for this task is that they are initially built to operate at very low temperatures, making them the safer option.

Explosion Proof Lights Installed in a Hazardous Area

Classification of Hazardous Locations and Devices

To ensure proper and safe lighting in the areas that remain vulnerable to hazardous accidents, the National Electric Code or NEC has set standards that classify the various risk levels meant for lighting to be approved as HAZLOC safe. This is meant to help you identify the right light for your location if it lies in the hazardous category.

The hazardous areas have been classified by the NEC based on groups, classes, divisions, and sectors. You can check the categorical identity of your area from the table on the right .

Hazardous environment classification

The following are the first three classifications identified by the NEC on a broad environmental basis:

  • Class I – These areas have flammable vapors or gases with topmost concentrations that can ignite when encountering electric sparks or open flames instantly.
  • Class II – These areas have a concentration of combustible dust.
  • Class III – These areas have a concentration of ignitable fires.

These classification groups have been further divided by the NEC into three subsets that are based on specific factory regulations. The further two divisions have the hazardous lighting locations being grouped into the sets based on their level of exposure to the dangerous materials.

  • Division 1 – The ignitable substances remain in the surroundings all the time, periodically during regular times, or releases during any maintenance activity or machine failure.
  • Division 2 – The ignitable substances remain present but in a controlled concentration due to proper ventilation and other release methods.

Those are the NEC classifications. You may have noticed that these classifications are more about the light location.

The next classification standards set by The Occupational Safety and Health Administrations or OSHA are for the categorization of lights based on their characteristics, model, and material concentrations.

The classes are denoted with letters from A-G:

  • Class I Gases – Start with letters A-D. The gases of Group A possess the highest explosion pressure such as Acetylene and the gases of Group D have the lowest pressure such as propane.
  • Class II Gases – Start with letters E-G. Group E has metal conducive dust such as magnesium, Group F has carbonaceous dust like coal, and Group G has non-conducive dust such as plastic, wood, and grain.
explosion proof lighting in hazardous locations
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About the Author

Neil Peterson is Chief Operating Officer at LED Lighting Supply. He has been active in the LED industry for over 10 years and is responsible for product planning and management as well as revenue and operations at LED Lighting Supply. Much of Neil’s time is focused on customer engagement for large commercial and industrial lighting requirements. When not working, he enjoys family time, camping, fishing, and sports..

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