Hazardous work areas present special challenges for the workers and businesses that must operate within them. These work areas are often confined rooms or containers like fuel tanks where vapors and gases from work activities can become concentrated to dangerous levels. As well as the obvious dangers posed by inhalation of these contaminants are the not so obvious dangers that can have lethal consequences if not properly addressed.

On April 27, 1917, an open light ignited gases that killed 121 people inside the Hastings Coal Mine in Colorado. On February 21, 2010, a man in Drummond, Ohio died when fumes from vehicle paint were ignited in his workshop, destroying the building. On February 18, 2010, a man in Arkansas was killed when the oil tank he was cleaning exploded. In May 2009, three workers were killed when a gas tank they were contracted to clean exploded.

Incidents like these have occurred numerous times in mines, factories, shipyards, power plants, and even homes. These incidents oftentimes happened because basic precautions were not followed, and/or improper equipment was used. In some cases such as the 1917 mine explosion, improper lighting was determined to be the definite source of ignition for the explosion. What they all demonstrate is the seriousness of the danger that gases and fumes in the work environment present.

While it may be obvious that high concentrations of vapors or fumes in the workplace present a fire hazard, it’s not as obvious that something as innocuous as a simple light can cause ignition of fumes or vapors and lead to an explosion. Just about anyone knows better than to light a cigarette near a gas pump. However, would they be so concerned with a spotlight? Because of these dangers and their complexity, standards have been created and assigned by federal bodies such as OSHA mandating the use of explosion proof lights in these hazardous work areas. There are different levels of danger and thus different requirements, and they are classified by the various hazards presented by different conditions.

Examples of hazardous work areas that require explosion proof lighting are fuel storage tanks undergoing repairs or servicing, automotive paint booths, power plants, oil tanks, storage areas for flammable chemicals and more. If a work area is going to be enclosed with little ventilation and chemical or fuel vapors present, or the work itself will produce fumes or gases, it’s a good bet a fire or explosion hazard will be present and explosion proof lights required.  The National Electrical Code defining hazardous areas is carried by OSHA and can be found under “HAZLOC” or Hazardous Classified Locations for a full description of what constitutes hazardous areas and the precautions necessary when working with them.

OSHA defines explosion proof lights as “An apparatus enclosed in a case that is capable of withstanding an explosion of a specified gas or vapor that may occur within it and of preventing the ignition of a specified gas or vapor surrounding the enclosure by sparks, flashes, or explosion of the gas or vapor within, and that operates at such an external temperature that a surrounding flammable atmosphere will not be ignited thereby.”

This is different from intrinsically safe lights which are defined by Underwriter Laboratories as basically any electronic circuit that is “incapable” of causing ignition, which puts them in an ultra high classification outside that of explosion proof lights. Rather than being totally incapable of producing ignition explosion proof lights achieve protection from ignition by reducing heat, incorporation of airtight seals, and rugged designs that can contain sparks and explosions within their housings without allowing them contact with the outside atmosphere.

Explosion Proof Lights are specifically designed for use in places where the danger of explosion or fires is or may be present. They come in several different classes and ratings, which are determined by the conditions the light is intended to be operated in. Larson Electronics for example offers this OSHA conforming Explosion Proof Light - Portable Cart - 24 Inch - 400 Watt Metal Halide - Class 1 Div 1 C&D. As you can see in its designation, it carries the Underwriters Laboratories' Class 1 Div 1 rating, which means it conforms to the highest ratings standards for hazardous area explosion proof lights. Since it carries the highest rating, and is classed “C&D”, this light can be operated in conditions where there is or may be continuous exposure to the flammable vapors and gases that can be produced by the presence of petrochemicals. This makes this light perfectly suited to jobs like the interior inspection of fuel storage tanks and bilge cleaning of large ships.

In addition to carrying the highest class and division ratings, this light's design is also well suited to jobs that require the ability to easily maneuver a high-powered light source. The cart-mounted design makes mobility easy requiring only that once assembled, the operator simply lift the handles and roll it into the desired position. In addition to its portability, the light can be rotated 360 degrees and vertically raised 90 degrees allowing a wide range of lighting directions.  It can be used in tanks with entry points that have diameters as small as 24 inches due to its design, which allows the removal of the light from the cart so it can be carried through the opening in parts and reassembled inside.

As well as being easily maneuverable, this light also makes use of two hundred and fifty feet of chemical and abrasion-resistant electrical cord, facilitating connection to power sources outside of the hazardous area, and still have enough length left to position the light wherever needed. This enhances the safety of the light, and adds to its effective mobility. With its connection to the power source made outside the hazardous environment, the chances of a spark from the connection causing an ignition are reduced.

This lamp operates at the maximum safe wattage for an explosion proof light with the incorporation of a four hundred watt metal halide bulb that can illuminate an area twenty thousand feet square, as well as project a beam of light for over five hundred feet. Explosion proof lights are typically available in strengths only up to four hundred watts, as anything higher tends to raise housing temperatures over safe limits. The Larson Electronics also uses an aluminum grid to protect the lamp and its Plexiglas lens cover. The Plexiglas lens cover is removable for cleaning and protects the lamp from the accumulation of dirt or debris while in use. This helps keep the need to clean or replace the lamp itself to a minimum while adding to the durability of the light as a whole.

This light's design is excellent for the worker who has to perform service or maintenance in a confined workspace with limited ingress, like an empty fuel tank or marine fuel cell. The mobility and convenience of lamps like the Larson Electronics Explosion Proof Portable Cart Metal Halide greatly reduce the dangers of a hazardous work area, not only by providing protection from ignition of flammable gases, but by also improving the ability to perform work safely and efficiently, by creating a well illuminated workspace.