What You Don't Know . . .

The most common atmospheric hazards associated with confined spaces are oxygen deficiency, oxygen displacement, flammable atmospheres, and toxic gases.

FRANCIS Bacon, a philosopher, once said that "knowledge is power." While this saying can be applied to many different situations throughout life, it has added value when talking about confined spaces in the work area. It's important to have a knowledge and understanding of confined spaces because the lack of same could result in serious injury, including death. Therefore, one must have a thorough understanding of what a confined space is.

Confined spaces can be found in many industrial settings, from public utilities to the construction industry. According to OSHA, a work area can be defined as a confined space if it meets all three of the following criteria:

  1. Limited openings for entry and exit. A confined space may be difficult to enter for performing repair work or general maintenance. If a work area has more than one way of escape, it still can be considered a confined space.
  2. The space is not intended for continuous human occupancy. A confined space was not designed with lighting, heating, ventilation, and air conditioning. These spaces include, but are not limited to, tanks and manholes.
  3. The space is large enough for you to enter and conduct work. If you cannot fit your body into a confined space, then you cannot become trapped inside.

If a space does not meet all three of the above criteria, it is not considered a confined space.

"Overall, confined spaces have limited entry and egress. It makes it difficult to get into and out of the work area," said Kent Freeman, captain and the coordinator of Technical Rescue Services for the Roseville Fire Department in California. He is the instructor of the Confined Space Awareness class at the Safety Center in Sacramento, Calif.

There are several types of confined spaces. Some confined spaces are very dangerous and pose an immediate threat to your life and health upon entry; others are less dangerous and pose little or no harm upon entry. They are categorized into non-permit and permit spaces. Non-permit spaces are spaces that do not, or could not, contain hazards that could cause serious harm, including death. You can enter these spaces and begin working without having to complete a written safety checklist.

Permit-required confined spaces have several characteristics. First, the space contains, or could contain, a hazardous atmosphere. Second, the space could contain a material that could engulf the entrant; a grain silo is one example. Next, the space has an inwardly converging wall or a floor that slopes downward and tapers to a small cross section. Finally, the last characteristic of a permit-required confined space is it may contain any other recognized serious safety hazard, such as an electrocution hazard or moving equipment.

If the space does not meet one of these characteristics, then it is not considered a permit-required confined space. When a space is determined to be permit-required, you can't enter the space and begin working until you have completed a written safety checklist.

Evaluating Confined Space Hazards
A confined space permit or written safety checklist is required by OSHA and should be completed before entering the confined space. This mandatory document serves as a reminder to entrants of what needs to be done before entering a confined space. Confined space permits determine the people authorized to enter the space, the purpose of entry, the time that will be spent working inside the confined space, and who will be the attendant who stays outside the confined space.

"OSHA regulations require good communications between the entrants and the attendant," said Freeman. "Through the use of portable radios, electronic hardwire systems, voice and hand signals, rope signals, light signals, or personal alarm devices, the attendant can maintain communication with the entrants to ensure their safety."

Also, the confined space permit asks entrants to identify the atmospheric hazards in the confined space, the kinds of equipment being used for safe entry, and additional checklists, if any, that need to be completed. "Certain industries pose different hazards," Freeman said. "It's important to understand the atmospheric hazards associated with your industry before entering the confined space."

Finally, the entrant should determine whether all the hazards have been eliminated before entering the confined space. There are two main types of hazards associated with confined spaces: atmospheric and physical.

Atmospheric hazards can interfere with the body's ability to transport and utilize oxygen or can have negative toxicological effects on the body. The most common atmospheric hazards associated with confined spaces are oxygen deficiency, oxygen displacement, flammable atmospheres, and toxic gases.

"Between 1980 and 1989, 65 percent of confined space deaths were a result of an atmospheric hazard," Freeman explained. "These hazards often cannot be seen or smelled, leading the entrant to believe they are in a clean atmosphere."

In the event an atmospheric hazard may be present, a multi-gas meter is used to determine levels of oxygen, carbon monoxide, hydrogen sulfide, and the concentration of combustible gas present in the work area.

The other major category of hazard found in confined spaces is physical hazards. Physical hazards cause the body to become physically stressed and can be detected using your senses of touch and sight. Engulfment is the most common physical hazard in the work area. For example, entrants can become engulfed and suffocate in the loose material that is stored in a grain silo. "Engulfment was the second-leading cause of deaths in confined spaces between 1980 and 1989," said Freeman. "Entrants weren't aware of the physical hazards associated with their industry, resulting in 13 percent of the confined space deaths."

Entrants also must consider other physical hazards, such as excessive noise, wet or slick surfaces, moving and rotating equipment, hot or cold conditions, and electrical energy.

With Work Completed, Cancel the Permit
Finally, once the work has been completed and the confined space is sealed, the permit should be canceled. This is the act of signing and dating it at the completion of the entry. This document should be filed for at least one year.

Confined space awareness can be very complex, but its absence can be lethal. There are classes and training courses offered throughout the United States to help educate workers on confined spaces. Remember, knowledge is power, and the lack of it can be deadly.

This article appeared in the November 2006 issue of Occupational Health & Safety.

This article originally appeared in the November 2006 issue of Occupational Health & Safety.

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