Posted on April, 2017

The risk of fire or explosion is a serious safety concern in industrial environments, warranting a number of codes, standards, and resources. Hazardous locations require specially designed products and unique installation techniques to mitigate the risks of flammable liquids, gases, vapors, and other substances.

Locations where these potentially dangerous substances exist stretch across industries with some of the biggest risks being found among chemical, petrochemical, and offshore oil platform applications.


Per the National Fire Protection Association (NFPA) 70, National Electric Code (NEC), the most widely used safety code for electrical systems in North America, hazardous locations and explosive atmospheres fall into three main classes:

  • Class I — Locations in which enough flammable gases or vapors may be present in the air to produce explosive or ignitable mixtures
  • Class II — Locations in which there are sufficient quantities of combustible dust to risk igniting or exploding
  • Class III — Locations in which easily ignitable fibers or flyings are stored, handled, or manufactured

Each class is further segregated into divisions, either Division 1 or Division 2, that define how likely a flammable material is to be found in a combustible concentration in a given area:

  • Division 1 — Combustible concentrations of hazardous materials exist under standard operating conditions, or when it is caused by frequent equipment failure or repair work
  • Division 2 — Combustible concentrations are regularly found, but in sealed containers or systems and are only cause for concern in the case of a rupture or breakdown

A third level of classification in the NFPA code identifies the particular hazardous materials present based on their properties (e.g., ignition current ratio, experimental safe gap). This grouping applies only to divisions in Class I and Class II locations. Examples of various hazardous materials in each group can be found below:

  • Group A — acetylene
  • Group B — hydrogen, butadiene, ethylene oxide, and propylene oxide
  • Group C — ethylene, cyclopropane, and ethyl ether
  • Group D — propane, acetone, ammonia, bezene, butane, ethanol, gasoline, methanol, and natural gas

Class I, II, and III locations are found across industries and applications, from the petrochemical and pharmaceutical industries to steel mills and powdered metal processing facilities. These conditions can even be found in industries that one might not expect, such as the food and beverage industry.


The electrical systems in hazardous locations require components specifically made to protect against the dangers of these environments. Designed to keep the explosions and flammable substances contained within the fittings, these components keep the hazards from spreading to the rest of the conduit system.

In order for fittings to be UL Listed as “suitable for hazardous locations,” they must first be tested by UL (UL HazLoc) to ensure they meet the Class, Division, and Group requirements of their intended application. Part of this testing process involves a mandatory corrosion test, from which stainless steel is exempt as its superior corrosion resistance properties are widely known across industries.


Gibson Stainless offers products designed to exceed all standard electrical industry practices. In addition, its hazardous locations product line consists of products designed for the added risks found in hazardous location applications.

To learn more about Gibson Stainless’ hazardous location fittings or our other product offerings, contact us today.

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