Anyone involved with workplace safety understands the critical nature of preventing accidents, particularly those involving employee safety. While there are many types of hazards in the workplace, those involving fire and explosions are, perhaps, the most devastating. It's often necessary to have buildings that will contain fires in certain areas. 

Fall protection in construction tops the list of top 10 cited OSHA violations for its fiscal year 2018 (October 1, 2017 through September 30, 2018), with the “Fatal Four” being:

• Falls – 338 out of 1,008 total deaths in construction in CY 2018 (33.5%)
• Struck by Object – 112 (11.1%)
• Electrocutions – 86 (8.5%)
• Caught-in/between* – 55 (5.5%)

But, what about deaths caused by fires and explosions?

According to The National Institute for Occupational Safety and Health (NIOSH) Facilities in Oil and Gas Extraction (FOG) data for 2015-2016, there were a total 92 fatalities in the industry. Explosions contributed to 13 of those deaths, or approximately 11 percent.

Explosive combustion or fire were the leaders in multiple-death incidents, in offshore rigs, and well servicing, intervention, or workover activities.

Let’s be honest here. Death by fire or explosion is a horrible way to die. Some victims probably never know what hit them, but their families are impacted forever.

Preventing these horrific accidents begins with understanding what hazardous locations are.

Hazardous Locations Defined

OSHA Publication 3073 defines a hazardous location as:

areas where flammable liquids, gases or vapors or combustible dusts exist in sufficient quantities to produce an explosion or fire. In hazardous locations, specially designed equipment and special installation techniques must be used to protect against the explosive and flammable potential of these substances.

Both the National Electrical Code (NEC) and the Canadian Electrical Code (CEC) define hazardous locations as:

“An area where a potential hazard (e.g., a fire, an explosion, etc.) may exist under normal or abnormal conditions because of the presence of flammable gases or vapors, combustible dusts or ignitable fibers or flyings.”

In the oil and gas industry, particularly in drilling and refining operations, flammable liquids, gases and vapors are always present.

The risk of fire or explosion must be evaluated and prepared for.

Hazardous (Classified) Location Designations

In North America, hazardous locations have been identified using a hazard Class/Division system. The Class designates the general nature of the hazards that may be present in the atmosphere. The hazard is present in sufficient quantities that it is ignitable, with the potential for fire or explosion.

For example:

• Class I locations contain flammable gases or vapors in sufficient amounts. Some examples are hydrogen, acetylene, ammonia, gasoline vapors, and methane.
• Class II locations contain combustible or electrically conductive dust. For example, metal dusts like aluminum and magnesium, wood dust, carbon-based dust such as coal, and organic dust like sugar, flour, and soap.
• Class III areas have sufficient ignitable fibers to present a potential fire hazard. Some examples include cotton lint, flax, and rayon.

Divisions refer to the probability of ignition, resulting in a fire or explosion.

Division 1 denotes a high probability of ignition of the Classified substance (I, II III) because the hazardous substance is continuously, periodically, or intermittently present, or from potential ignition caused by equipment or devices operating under normal conditions.

For example, electric motors will create sparking in the windings during normal operations. Phones, radios, and similar equipment are capable of igniting the classified substances listed above. Therefore, these electrical and electronic devices must be of intrinsically safe design and construction.

Even smoke detectors, and other alarm devices and systems meant to warn and protect workers from emergency incidents can contribute to the problem if not intrinsically safe or housed in the proper, fireproof and/or vapor-tight enclosures.

Division 2 means that the classified substance (I, II, III) has a low probability of ignition under normal operating conditions. Leaks, spills, or equipment malfunctions may cause sufficient quantities to form a volatile, ignitable mixture.

Let's look at some examples. Class I locations have flammable gases or vapors, such as gasoline vapors. An automobile repair shop can be a Class I location. Gasoline and oil spills can be large enough to ignite, but the probability is low. Therefore, it would be a Class I, Division 2 location. Lighting a cigarette may have little consequence.

However, a petroleum refinery that produces gasoline will have areas where vapors collect intermittently or even continuously in large enough quantities to ignite and explode. Those areas will be denoted as Class I, Division 1 locations. No Smoking signs will be posted around these areas.

An example of a Class II, Division 1 location would be a feed mill or storage area where grain dust is normally present in the atmosphere. The sparks created by a motor running could ignite the grain dust.

It should be noted that the European classifications are slightly more complex in their designations, divided into multiple Zones and Groups. They are based on the International Electrotechnical Commission IEC 60079 Explosive atmospheres standards.

Due, in part, to the global economy and reach of the oil and gas industry, the European standards are being applied to North American locations. They are more complex, but at the same time, more precise. This can more efficiently standardize regulations in the worldwide marketplace.

Why Understanding Hazardous Locations is Important

As mentioned above, worker safety is of paramount importance on the job site. You know that intimately. It’s part of your job, your responsibility … and your sometimes emotional viewpoint or passion. 

And in the oil and gas industry, particularly on offshore rigs where weather, water, and isolation present unique challenges for abatement, rescue, and extraction, the stakes are even higher. In fact, there are even offshore classification societies that dictate the rules and regulations that offshore vessels and operations must follow. 

Not only must risk analysis be done initially, upon installation and commissioning, but continuously during operation. Even decommissioning operations require a watchful eye.

Add that to the fact that many of the chemicals used to facilitate the mining operation, or released during the extraction process are also flammable, and the risks increase.

Risk analysis, including the classification of the atmosphere’s potential hazards, is the only way to reduce the possibility of fire and explosion. Once completed, the hierarchy of control can be applied to equipment, processes, and personnel. It could give you recommendations about the class of doors, walls or buildings to contain fires should an accident occur. 

SSRG sells a range of modular buildings that can be used in offshore settings, like accommodation units, control rooms, mudlogging, and much more.