The skinny on permit-required confined spaces

There’s nothing new about confined spaces or their hazards. In Roman times, the emperor Trajan sentenced criminals to clean sewers, an occupation known to be particularly dangerous.

The Occupational Safety and Health Administration defines a confined space as one whose size and shape allows an employee to enter and perform assigned work but is not designed to be occupied continuously and has limited or restricted means for getting in and out. Examples include tanks, storage bins, vessels, silos, hoppers, vaults and pits.


Confined spaces can be awkward and uncomfortable to work in. What’s more, hazards are generally even more severe when they exist in confined spaces. That’s why OSHA requires special precautions and even permits for a great many confined-space tasks.



OSHA defines a permit-required confined space as one that has one or more of the following:

1)      A hazardous atmosphere that could cause a person to become ill, incapacitated, unable to escape without aid or even to die. The atmosphere may be hazardous due to:

-          flammable gas, vapor or mist levels more than 10 percent above the substance’s lower flammable limit

-          airborne combustible dust at or above that limit (OSHA notes that “this concentration may be approximated as a condition that obscures vision at a distance of 5 feet)

-          an oxygen concentration below 19.5 percent or above 23.5 percent

-          aconcentration of any substance for which a dose or a permissible exposure limit (PEL) in Subpart G or Z of Part 1910 and that could result in employee exposure in excess of such dose or PEL

-          any other atmospheric condition immediately dangerous to life or health

2)       An engulfment potential that could lead to a worker being immersed and buried or smothered by a liquid or a flowing solid, like sand or grain.

3)       A potentially entrapping design such as walls that converge inward or a floor that slopes and tapers down.

4)       Any other recognized serious health or safety hazard, such as falls or excessive heat or noise.


Employer requirements

OSHA’s permit-required confined space regulation requires employers to develop and follow a written confined space entry program, which “shall be available for inspection by employees and their authorized representatives.”


The program provides for determining and stating the conditions that will allow safe space entry – and verifying that those conditions will be maintained while anyone works in the space. Such work will thus be allowed only when the space meets listed criteria and after obtaining a permit that lists specific information about the space and entry. It is also the employer’s responsibility to:

-          Train employees to safely perform confined space tasks

-          Develop safety procedures, including rescue plans and personnel

-          Identify and test the atmosphere in a confined space that is to be entered

-         Retest the atmosphere in the space before workers enter it – with the

     authorized entrant and an authorized representative allowed to observe.

-          Flush, ventilate or otherwise eliminate or control atmospheric hazards before allowing workers in the space

-          Keep unauthorized employees out of such spaces by the posting of signs or other warnings, the use of barricades or other appropriate means.


Roles and responsibilities

To help assure worker safety in permit-required confined spaces, OSHA has also described several key employee roles. Authorized entrants may enter only after the air is tested and found safe. Once in the space, these workers must be vigilant for any change in conditions. They must be familiar with the potential hazards listed on the permit and the signs and symptoms of lack of oxygen and other risks. Authorized entrants must know what equipment to use and how to use it. That includes personal protective gear, tools needed for the task, equipment for communicating with the attendant and some kind of personal retrieval system.


According to OSHA, each authorized entrant has to use a chest or full body harness attached to a retrieval line. A wristlet system may be used only if the employer can demonstrate that other systems are impractical or dangerous. Also, despite the protections in place, work inside the space should be completed as efficiently and quickly as possible. Workers should be instructed to leave the space immediately if they suspect trouble, or if the attendant gives an order or sounds an alarm.


Attendants must remain on duty outside an occupied permit-required confined space. They must study the permit to understand the potential hazards of the space and the signs and symptoms of trouble.


An attendant must:

-          monitor and count who’s in and who’s outside the space

-          stay in touch with authorized entrant(s) working inside

-          keep unauthorized people away from an occupied space

-          order immediate evacuation if the entrant shows signs of hazardous exposure, if the attendant can’t perform duties safely, or if a situation outside the space could endanger workers within

-          summon rescue and emergency services when needed to evacuate workers


Entry supervisors oversee the operation. They make sure testing and other permit requirements are met, then sign the permit so workers can enter. The entry supervisor also must be familiar with the hazards in the space, assure the availability of rescue and emergency services, and stop work in the space and cancel the permit when the task is completed or when conditions develop that make the work unsafe.


Rescue and emergency service personnel may work for the employer, or for an outside service. But it’s always the job of the employer with the permit-required confined space to be sure rescuers are ready, willing and able to handle their duties.


Reminders for employees

Doing your part as an employer is just one component in a program to keep workers safe during confined space work. It’s equally important that employees do their part, including participating in training and applying what they’ve learned. Encourage your workers to understand and observe these basic safety precautions that can help keep them safe.


Employees should:

-          plan tasks and assemble equipment so work in the confined space can be performed quickly

-          be sure any steam, water, heat or power lines going into the space are cut off and locked and tagged

-          not enter the space if they feel unwell or have been using alcohol or any drugs

-          pay close attention to how they feel while in the space

-         leave immediately if they have trouble breathing, feel tired, dizzy, nauseated, etc.

-          avoid taking food, drinks or cigarettes into the space

-          make sure the space is adequately ventilated


Vigilance and vigor

Hearing conservation and permit-required confined space programs don’t have a great deal in common in terms of the hazards they address. But compliance with each of these bedrock OSHA standards requires a great deal of vigilance and vigor – by you, as the employer, and by your employees. Although hearing loss is not a “life and death” matter like asphyxiation in a confined space, adherence with both sets of OSHA requirements can have a dramatic impact on the life and health of your greatest business asset: your workforce.


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