- Identify characteristics and examples of a confined space
- Identify hazards of confined spaces
- Identify the differences between permit-required and non-permit-required confined spaces
- Identify specific requirements of a Permit-Required Confined Space Program
- Identify the requirements of the permit system and the information a permit includes
- Recognize the responsibilities of personnel who work in or attend permit spaces
- Identify rescue resources and how to plan for emergencies
Available in English, Spanish
Research, Centers for Disease Control & Prevention
Confined spaces are enclosed or partially enclosed spaces of a size such that a worker can squeeze entry for performing assigned work through a narrow opening—they’re tough to get in and out of, tight spaces. These spaces are normally only entered to perform specific tasks and then barricaded to prevent unauthorized access.
Examples include storage tanks or bins, mixing tanks, railroad tank cars, silos, vaults, and pits. Think of any large tank used for holding liquid. Sometimes, these big storage containers need to be cleaned out, so you send a worker to get inside and they’re completely surrounded by walls of the structure, with only a small entry/exit hatch for escape if things go awry. Confined spaces create the ideal conditions for the onset of claustrophobia. Confined spaces can be large or small and above or below ground.
By their very nature and configuration, many confined spaces may foster a hazardous atmosphere. These are normally poorly ventilated areas, so the release of vapors which might otherwise be released into the open air can create an oxygen-deficient, toxic, combustible, or otherwise harmful atmosphere. Confined spaces kill when several unexpected situations develop. Exposure to these atmospheres can result in immediate asphyxiation, acute or chronic poisoning, or impairment that can result in injury.
Asphyxiation is the leading cause of death in confined spaces. How does that happen?
Oxygen deficiency is one probable factor contributing to confined space accidents. This is when the air in a confined space is consumed by chemical or biological reactions, diluting the percentage of oxygen in the immediate atmosphere to below 21%, causing increasingly negative physiological responses as that percentage declines.
Oxygen displacement is another killer in confined spaces. Typically, this is when inert gas is present at levels that remove oxygen from the chamber, essentially crowding out the normal air we breathe and replacing it with, say colorless, odorless gases like nitrogen or carbon dioxide, creating a situation of complete suffocation for workers.
Other common, problem situations in confined spaces involve flammable atmospheres, toxic gases and solvents, each posing different, specific hazards that have killed high-risk workers in the past.
A permit-required confined space is an area which:
Contains or has the potential to contain a hazardous atmosphere
Contains a material with the potential to engulf someone who enters the space
Has an internal configuration that might cause an entrant to be trapped or asphyxiated
Contains any other recognized serious safety or health hazards
Your company’s Permit-required Confined Space Entry Program is its overall policy and plan for protecting you and other employees and contractors against confined space hazards, and for regulating entry into its permit-required spaces. Before you may enter a permit space, your supervisor and/or the attendant must take any measures necessary to isolate the permit space and eliminate or control hazards. These measures include lockout or tagging of equipment to ensure that it does not present a hazard.
Measures also include testing and monitoring the air for contaminants and adequate oxygen, as well as purging, ventilating, and flushing unsafe atmospheres or chemicals from the space. If a permit space requires forced air ventilation, the ventilator must eliminate or reduce hazardous atmospheric conditions to within acceptable limits, employing PPE as necessary to accomplish this, and maintain a safe atmosphere until the work is completed and personnel have left the space. Before you may enter a permit space, your supervisor and/or the attendant must test the internal atmosphere of the space with calibrated, direct-reading instruments.
OSHA requires that your employer provide any necessary equipment at no cost to you to ensure your safe entry and exit of the permit space. Equipment includes ventilation, testing and monitoring instruments to maintain an acceptable atmosphere quality. Equipment may also include communication devices to monitor your status and provide evacuation alerts, any personal protective equipment necessary for adequate protection, and appropriate lighting to enter, work, and exit safely. Your employer must also provide barriers or shields to protect you from external hazards, such as electrical hazards or sources of extreme heat and cold, ladders or other equipment for safe entrance and exit, and all rescue and emergency equipment for rescuing entrants.
Employers must ensure that employees working directly in a permit space perform specific duties, in addition to knowing the hazards and symptoms of exposure.
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