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Confined Space Rescue
Building a Confined Space Entry Plan

by: Mark A. Brown

For years, workers have entered manholes, railcars, vaults and a pit or two as part of their jobs without thinking about the potential dangers. Think back to when you entered spaces to do routine tasks, unknowingly at the time that you may be risking your life. Workers are subject to serious life threatening risks every day. Every year unprepared workers enter a confined space with fatal results.

Some workers just ignore the dangers of entry, others simply do not know. It seems simple enough! Entry into a space that contains an asphyxiating atmosphere is a mistake that is often punished with fatal results. What about hydrogen sulfide? This one and other toxic contaminants give little warning and are equally deadly. Unfortunately, history tells us that confined space accidents usually result in multiple deaths as would be rescuers rush in to save the entrant and suffer the same fate.

Preplanning. Preplanning. Preplanning. I just cannot mention it enough. Often I read news stories about accidents where would be victims are quoted as saying "I wish we knew that vault was filled with Methal Ethel Bad Stuff." That's my point. Preplanning is the most important part of any successful confined space program. Yea, we have the coolest gear and could rescue anyone out of that vault, but do we really have an idea of what could happen? One part of preplanning is the identification of anticipated hazards. Anticipated is the key word here. By identifying the hazards and providing the appropriate controls, a confined space entry can become a safe and routine part of a workers' everyday responsibility.

Confined Spaces Defined

OSHA defines confined spaces as work areas which have adequate size and configurations for employee entry. Confined spaces have limited means of entering and exiting and they are not designed for continuos employee occupancy.

A permit-required confined space is a space that has the potential to have one or more of the following hazards: Atmospheric conditions (toxic, flammable, asphyxiating), engulfment, configuration or any other recognized serious hazard.

Any person that passes through an opening into a permit-required confined space (or enclosed space) is considered to have entered by OSHA. This means any part of the entrant's body has gone through the opening.

Hazards of Confined Spaces

  • Oxygen Hazards

    Common household products such as grease or oil have a greater potential to catch fire when exposed to high levels of oxygen. Atmospheres containing too little oxygen result in physical effects to workers in the space.

    According to the OSHA Standard the following are defined as high and low oxygen levels.

     23.5% & Above High Oxygen Levels
     20.8% to 21% Normal Oxygen Levels for Air
     19.5% & Below Low Oxygen Levels

    According to the NIOSH Technical Report on Respiratory Protection the following signs and symptoms are observed when the human body experiences oxygen deficiency.

     16 to 12% Deep breathing, accelerated heartbeat, impaired attention, impaired thinking, impaired coordination.
     14 to 10% Very faulty judgment, very poor coordination, rapid fatigue from exertion that may cause permanent heart damage, intermittent breathing.
     10% or Below Nausea, vomiting, inability to perform vigorous movement or loss of all movement, unconsciousness followed by death.
     Less than 6% Spasmodic breathing, convulsive movements, death in minutes.

  • Toxic Hazards

    Toxic atmospheres include gases, vapors or fumes that have poisonous effects. Some toxic atmospheres are immediately fatal (Immediately Dangerous to Life and Health - IDLH). Common toxic hazards include hydrogen sulfide, suffer dioxide and carbon monoxide.

  • Flammable Hazards

    A flammable or explosive atmosphere contains gases, vapors or dusts in concentrations high enough to ignite or explode. Common flammable atmospheres include methane gas, solvent vapors from tank residues or combustible dusts such as grain dusts, flour or metallic paint pigments.

  • Energy Hazards

    These hazards involve contact with electrical equipment, steam, motorized and other sources of heat inside the space. This types of equipment include pumps, mixers and impellers.

  • Engulfment

    Engulfment is defined as a liquid or solid substance that traps the entrant. Death can occur due to inhaling the substance or by surrounding the entrant, thus causing strangulation, constriction or crushing.

  • Configuration

    Configuration is the internal shape or size of the space. An entrant can be trapped or asphyxiated by inwardly converging walls or by a floor which slopes downward and tapers to a smaller cross section.

  • Other Hazards

    Other hazards can include falls due to loose rungs on fixed ladders in manholes, slippery surfaces due to liquid in tanks or sloping floors, noise exposure due to sound reflected off of walls within the space, personal protective equipment that is used improperly or the specific type of work being performed.


    As you can see, discussing confined spaces can take some space (none intended). We've only touched the surface in this article. Next time, I'll explain the duties of entry supervisors and entry personnel. I'll also touch on some pre-entry planning. Send me your feedback! Be Safe!

    Mark Brown is a vice president at Lee & Associates in charge of technology. You can find him high upon a mountain... somewhere... with a portable computer of course.

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