Explosion Proof Lighting

What are Explosion Proof Lights?

Explosion-proof lighting (or hazardous location lights ) is designed to be used in hazardous environments and hazardous locations where there's a risk of explosion/ignition due to the presence of flammable gasses, liquids, or dust and safety is paramount. Engineers design explosion-proof lighting systems so that they can contain an explosion if created inside the fixture. More importantly, it's inherently designed to prevent that explosion from escaping the fixture. This hazardous area lighting is commonplace in industrial and commercial hazardous environments, such as oil and gas facilities, chemical plants, underground mines, water treatment plants, paint spray booths, and grain elevators. LED explosion-proof lights are known for their great light quality and energy efficiency over traditional HID explosion-proof lights.

How To Determine If a Light Is Explosion-Proof

In the USA, the light requires a certification to UL844 standard. Beyond that, you have to determine what certification applies - Class 1 Division 1 and Class 1 Division 2 are the most common. There are other certifications – like ATEX, that apply to other countries. In the USA, Canada, and locations near here, make sure it is UL844 certified.

Difference Between Flame Proof and Explosion Proof Lighting

A flameproof light is one that's built with materials that inhibit flames. Explosion-proof fixtures are designed to operate in an explosive environment. Never use a flameproof light in place of an explosion-proof light. Only certified explosion-proof LED lights will work in these types of environments.

Are All LED Lights Explosion Proof?

Not all LED lights are explosion-proof. The fixture tested under the UL844 certification meets explosion-proof requirements. Do not confuse vapor-proof with explosion-proof, they are not the same thing. Never use vapor-tight fixtures in an environment where explosion-proof lighting is required.

Classifications of Explosion Proof Lighting

Class I Locations: Flammable Gases, Vapors, or Liquids

Class I are areas where vapors and/or gases can ignite and are present in enough quantity to create an explosion. Vapors are gases present over a liquid material under normal conditions. But they may emit gases that may be flammable.

Division 1

Division 1 are areas where the flammable vapors or gases are present all or most of the time under normal operating conditions.

Division 2

Division 2 is areas where ignitable gases or vapors are not present under normal operating conditions. Or they are areas next to Class I, Division 1 locations where barriers, walls, or doors do not exist.

Groups of Class 1 Locations

There are 4 groups defined for Class 1 Locations that represent the type of gas or vapor.

• Group A: Acetylene
• Group B: Hydrogen
• Group C: Ethylene
• Group D: Gasoline / Propane

Class II Locations: Combustible Dust and Hazardous Substances

These are locations that are hazardous because of the presence of combustible dust. The dust must be present in large enough quantities to create an explosion or fire. To be classified as dust, the material must be 420 microns (0.420 mm) or smaller.

Division 1

This is similar to Class 1 Division 1. These locations contain combustible dust which is suspended in the air in quantities that can produce an explosion if ignited under normal operating conditions.

Division 2

This is similar to Class 1 Division 2. These locations do not have combustible dust under normal operating conditions. However, there are times when this area may accumulate dust in quantities large enough that when ignited causes an explosion.

Groups of Class 2 Locations

There are 3 groups defined for Class 2 Locations and represent the type of dust or combustible particle.

• Group E: Electrical-conductive dust
• Group F: Carbonaceous dust
• Group G: Agricultural and polymer dust

Class III Locations: Ignitable Flyings and Fibers

Class III locations are areas that have the presence of ignitable flyings or fibers. It's important to note that these fibers or flyings are not likely to be in suspension during normal operating conditions. These are conditions that sometimes happen but not always.

Division 1

Class III, Division 1 locations have equipment that produces the ignitable fibers or flyings. This location has concentrations of ignitable flyings or fibers that exist all or some of the time under normal operating conditions.

Division 2

Class III, Division 2 locations outside of the manufacturing area that are exposed to ignitable fibers or flyings. These hazardous areas have concentrations of ignitable flyings or fibers that typically do not exist under normal operating conditions.

Groups of Class III Locations

There are no groups in Class III locations.

Intrinsically Safe Lights

Intrinsically safe lighting fixtures are a form of explosion-proof lighting. But they differ in the way they're designed. By design, they cannot create an explosion or spark. For the most part, they tend to be low power, low voltage lighting, and often are battery-powered.

Difference Between Class 1 Division 1 and Class 1 Division 2

• Flammable gases, vapors, and liquids are always present: use Class 1 Division 1
• Flammable gases, vapors, and liquids are present some of the time: use Class 1 Division 2

Can You Substitute a Class 1 Fixture for Classes 2 or 3?

No. Unlike divisions described above, you cannot swap an explosion-proof lighting fixture among classes. It is either rated for the Class you need or it isn't.

Can you use a Division 1 Fixture of a Class in a Division 2 Area of the Same Class?

Yes, that assumes that both have the same grouping certification. For example, C1D1, Group C can substitute in C1D2, Group C areas.

Difference Between Class 1, Class 2, and Class 3

• Class 1: Gases - Areas in which flammable gases or vapors are present.
• Class 2: Dust - Areas in which combustible dust suspends in the air or can accumulate on equipment.
• Class 3: Fibers  - Areas in which ignitable fibers are present.