How Big Is a Confined Space?

Jun 5th, 2011 | By | Category: Featured Articles, Health and Safety

During a recent audit, I discovered that many of my colleagues and I had been taught to apply the U.S. Occupational Safety and Health Administration’s (OSHA) confined space standard (29 Code of Federal Regulations 1910.146) incorrectly. The question that came up was related to identifying “what is a confined space,” which I find to be one of the more frequently debated questions among safety professionals. Because this discussion took us beyond the basic standard and into the Compliance Directive and the preamble to the standard, I thought it would be worthwhile to share the details with others who may face similar situations.

The confusion comes up (at least for me) in reading the definitions in the standards.  A confined space is defined as one that (among other things) “is large enough and so configured that an employee can bodily enter.”  This statement is followed by the definition of “entry,” which says in part that entry “is considered to have occurred as soon as any part of the entrant’s body breaks the plane of an opening into the space.” This has led safety professionals to the interpretation that any space into which a worker might extend his or her head or arms should be considered a confined space (if it met the rest of the definition about not being designed for continuous occupancy and having limited or restricted means of entry or exit), even if the space is too small to accommodate the employee’s entire body.

Further investigation, however, shows that OSHA never intended to apply the confined space standard in this way, and the proof is clearly laid out in the preamble to the 1993 final rule. The preamble notes that several commenters on the original proposed rule said that the definitions of “confined space” and “entry” were confusing (obviously they were right), and some commenters suggested that small spaces could be just as hazardous and should be subject to the rule.

OSHA’s response was as follows:

The Agency has not adopted this suggestion. While OSHA is concerned that spaces that are too small for complete bodily entry may pose hazards for employees, the Agency did not intend to cover such spaces under the permit space standard. OSHA believes that the NPRM preamble discussion of permit space incidents and of proposed provisions clearly indicates that the proposed rule was intended to cover only spaces that were large enough for the entire body of an employee to enter. As commenters have correctly noted, the proposed definition of “permit required confined space” did not cover the “small” spaces. Such spaces do not meet the definition of “confined space,” nor do they pose hazards comparable to those associated with confined spaces. Since an employee cannot totally enter such spaces, he or she should not have difficulty withdrawing from the space. In order for a space to be considered a permit-required confined space, it must first be a confined space. A space that cannot be entered is not confined; therefore, it does not pose hazards related to the difficulty of exiting the space.

More recent agency interpretations are consistent with this position. The 2008 Letter of Interpretation on “Determining whether an aircraft fuel tank is considered a confined space” makes clear that if an employee cannot fit his or her entire body into the space, then it is not a confined space.

Of course, there are spaces into which some employees fit but others do not. I would recommend that if a very small adult (for example 4 feet 11 inches tall and 90 pounds) will fit into the space, the space should be managed as a confined space. It is also important to recognize that it is the capacity and configuration of the space, not the actual entry practices, that determine whether a space is subject to the rule. So, if an employee will fit inside the space and it meets the other elements of the confined space definition, it must be managed as a confined space, even if written procedures call for employees only to reach inside with their hands.

Finally, you must keep in mind that other sections of the OSHA rules require you to protect employees from the types of hazards that may be encountered when working in spaces that are too small to be considered confined spaces. These hazards may include exposures to toxic substances and air contaminants, machine guarding issues, and control of hazardous energy. The Compliance Directive for the confined space standard (CPL 02-00-100) has a question and answer section in Appendix E that includes the following:

6. How will OSHA address a space that does not satisfy the criteria for a confined space but that potentially contains a hazardous atmosphere?

Employers must comply with the permissible exposure limits and other requirements contained in standards addressing specific toxic substances and air contaminants, to the extent applicable, in all spaces in which employees may be present. In addition, the respiratory protection standard, 29 CFR 1910.134, applies where an employee must enter a space in which a hazardous atmosphere may be present and no other specific standard applies. The respiratory protection standard contains special precautions for working in atmospheres that are oxygen deficient or immediately dangerous to life or health.

I hope this information will help clarify what has been a confusing standard and will assist you in easing the burden of confined space management for your clients.

About the Author

Barbara Jo Ruble, QEP, CPEA is the President of Specialty Technical Consultants, a management consulting firm that works globally to enhance its clients’ environmental, health and safety performance. She has more than 30 years of experience helping corporations develop, assess, and improve their EHS management systems and compliance programs. She is the primary author of OHSAS 18001/OSHA-VPP Occupational Health & Safety Management Systems: A Complete Implementation Guide, published by Specialty Technical Publishers of Vancouver, Canada.

Image: Confined by Ryan Bourne, Merrylands, NSW, Australia.

This article originally appeared in The Advisor, a technical publication of the American Society of Safety Engineers’s Consultants Practice Specialty.

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4 Comments to “How Big Is a Confined Space?”

  1. Wm. E. "Bill" Kelly says:

    Perfectly explained and referenced. Have had numerous debates with folks
    over the years and trying to explain the nuances of the wording just confused
    many. Great job putting this one to rest!

  2. Judy says:

    Thank you for this perfect article!!! I have tried to explain this over and over again and they just dont get it. This makes it so clear and I will be using this in an upcoming training for our CSE policy.

  3. Excellent work. You did well to disinterred an important information and valuable references.

  4. Excellent article, I see the same confusion when I train or go out in the field to conduct audits. Wish more people knew about this type of info that can be found in the preambles, versus the actual OSHA standards.

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