When are Oil Wells an Explosive Hazard?


Courtesy of Larson Electronics LLC

Contrary to popular belief, an oil well can be an explosive hazard even when it is not in operation (pumping steady). An EnergyWire review of federal labor statistics cited that the oil and gas sector experiences the most deaths from fires and explosions, compared to other private industries.

Risks of Explosive Elements around Oil Wells

A recent explosion in 2014 at an oil and drilling site in Greeley, Colorado is an example of how indirect contact with explosive elements in or near the facility can be hazardous. According to Dale Lyman, fire marshal for the Greeley Fire Department, the explosion was linked to flowback from a well that was composed of water, debris and flammable components. A worker, who was parked near the site, did not notice the accumulation of flammable compounds in the location, and ignited the mixture from the truck’s catalytic converter. Unlike building fires, oil well explosions are extremely difficult to deal with. During the explosion, emergency crews used a combination of water, dry chemicals and foam (designed to restrict explosive vapor emissions) to suppress nearby flames.

Controlling Sparks and Explosive Hazards

Flowbacks are not the only fire hazards workers need to watch out for in an oil well facility. Any electrical equipment on or near the location that can produce a spark could potentially ignite a combustible compound. As mentioned earlier, the well does not actually have to be operating for such combustions to occur.

“The biggest risk of [an oil well] fire is any spark potential, in my opinion. Other works can increase risk, such as naked flame works. The risk of fire is heightened significantly if a gas release is incurred. Any gas release requires an ignition source. There are controls and barriers put in place to prevent a release actually finding an ignition source, such as an open electrical box or loose wires that may be live,” highlighted Heidi Vella from Offshore Technology.

Common sources for the ignition of flammable gases or vapors near oil sites include: internal-combustion engine sparks, open flames from any source, smoking, welding operations, electrical power tools, two-way radios and portable generators. Vella further explained that new, unregulated equipment, such as mobile phones, carry serious risks when used near an oil well. This is a problem because most smartphones are not intrinsically rated or support explosion proof properties. In the event a phone battery is dropped, it could cause a spark, which could lead to the ignition of a nearby flammable compound.

NFPA Regulations Surrounding Fire Hazards

There are several regulatory institutions that provide best practices for safety in oil drilling establishments. Such agencies include the American Petroleum Institute (API), the Occupational Safety and Health Administration (OSHA) and the National Fire Protection Association (NFPA). To prevent injuries related to fires on oil well sites, the OHSA sets forth guidelines on creating exit routes, emergency planning and fire management. The group outlines suggestions for the proper storage of flammable and combustible liquids, as well as access to flame-resistant clothing.

Explosion proof lighting equipment is highly effective in preventing fires on and near oil sites due to their ability to minimize the creation of sparks. The National Electric Code (NEC) categorizes such locations under Class 1 (Article 501). Under the code, the classification is further broken down into the following (two) divisions:

Class I, Division I (C1D1):

(1) In which ignitable concentrations of flammable gases, flammable liquid–produced vapors, or combustible liquid–produced vapors can exist under normal operating conditions, or

(2) In which ignitable concentrations of such flammable gases, flammable liquid–produced vapors, or combustible liquids above their flash points may exist frequently because of repair or maintenance operations or because of leakage, or

(3) In which breakdown or faulty operation of equipment or processes might release ignitable concentrations of flammable gases, flammable liquid–produced vapors, or combustible liquid–produced vapors and might also cause simultaneous failure of electrical equipment in such a way as to directly cause the electrical equipment to become a source of ignition

Class I, Division II (C1D2):

(1) In which volatile flammable gases, flammable liquid– produced vapors, or combustible liquid–produced vapors are handled, processed, or used, but in which the liquids, vapors, or gases will normally be confined within closed containers or closed systems from which they can escape only in case of accidental rupture or breakdown of such containers or systems or in case of abnormal operation of equipment, or

(2) In which ignitable concentrations of flammable gases, flammable liquid–produced vapors, or combustible liquid–produced vapors are normally prevented by positive mechanical ventilation and which might become hazardous through failure or abnormal operation of the ventilating equipment, or

(3) That is adjacent to a Class I, Division 1 location, and to which ignitable concentrations of flammable gases, flammable liquid–produced vapors, or combustible liquid–produced vapors above their flash points might occasionally be communicated unless such communication is prevented by adequate positive-pressure ventilation from a source of clean air and effective safeguards against ventilation failure are provided.

This classification includes areas where flammable gases, flammable liquid-produced vapors, or combustible liquid-produced vapors may be present in amounts that could produce an explosion or ignition. When adhering to NEC guidelines, electrical devices may either be intrinsically safe or explosion proof, while hand tools must be manufactured from non-sparking material, such as wood, rubber or plastic.

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