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Confined Spaces in Construction

Last May, OSHA published its final rule regarding confined spaces in construction. Since that time, there have been many questions about the differences between the new construction standard and 29 CFR 1910.146, “Permit-required confined spaces.” In this installment of “Voice of Experience,” we will take a closer look at both standards in an effort to clear up any remaining confusion.

“Confined Spaces in Construction” is the title of 1926 Subpart AA, the recently released construction standard. Before Subpart AA was published, 1910.146 was the only OSHA standard that addressed permit-required confined spaces, and 1910.146 assumes that the host employer and the controlling employer are one and the same. But over time OSHA realized that because construction activities may involve more than one employer on a job site – which is not usually the case with general industry jobs – the controlling employer is not always the host employer. In fact, there may be a variety of contractors working on or in a space, building the space or entering the space. There was clearly a need for these issues to be addressed by OSHA, and the agency has now done so in 1926 Subpart AA.

Given the subject matter of the new construction standard and 1910.146, it is no surprise that there are a number of similarities between the two. However, Subpart AA is much more detailed than 1910.146. This is particularly apparent in 1926.1209, “Duties of attendants,” and 1926.1210, “Duties of entry supervisors,” which explicitly address accountability and responsibility for protection of workers on job sites.

The new construction standard also requires much more detailed and coordinated activities from host contractors, independent contractors and subcontractors working on the same job site. A competent person must complete a work site evaluation, identifying confined spaces as well as permit-required confined spaces. Additionally, constant monitoring of air quality is required when possible rather than the periodic checks mandated in 1910.146. There also must be constant monitoring of possible engulfment hazards as well as the opportunity to suspend a permit rather than canceling and reissuing it.

Another important point of understanding is that the general industry standard indicates that the employer shall evaluate work sites while the construction standard states that a competent person shall evaluate them.

There are a considerable number of definitions in Subpart AA, far more than you will find in 1910.146. All of them can be reviewed in standard 1926.1202. New terms include “controlling contractor,” “early-warning system,” “entry employer,” “host employer” and “non-entry rescue.” The definition of a confined space in 1926 Subpart AA is the same in 1910.146, except that examples of confined spaces are omitted in Subpart AA. OSHA also includes a clarification in the new construction standard that a trench is not considered a confined space. Trenches and excavations are specifically covered in 1926 Subpart P.

Many Subpart AA definitions have been modified and clarified from the way they appear in 1910.146. For instance, the definition of “entry” in the general industry standard reads as follows: “‘Entry’ means the action by which a person passes through an opening into a permit-required confined space. Entry includes ensuing work activities in that space and is considered to have occurred as soon as any part of the entrant’s body breaks the plane of an opening into the space.” In Subpart AA, the definition of “entry” is “the action by which any part of a person passes through an opening into a permit-required confined space. Entry includes ensuing work activities in that space and is considered to have occurred as soon as any part of the entrant’s body breaks the plane of an opening into the space, whether or not such action is intentional or any work activities are actually performed in the space.”

Readers will likely notice that some Subpart AA definitions refer to OSHA’s Multi-Employer Citation Policy (see and indicate which employer creates, controls, corrects and/or exposes employees to hazards in the workplace. For example, “controlling contractor” is a new term defined as “the employer that has overall responsibility for construction at the worksite.” Per Subpart AA, one of the responsibilities of the controlling contractor is to obtain site-specific hazard information before any entry into a space is permitted. All of the information must be shared with all entry employers before operations begin. The 1910.146 standard never went this far. In the past, under the Multi-Employer Citation Policy, this information was expected to be shared by all on-site subcontractors. Unfortunately, failure to meet expectations led to accidents and loss of life in confined spaces.

A related point made in 1926 Subpart AA is that if the controlling contractor owns or manages the property, that contractor is also considered the host employer. Often the owner of the system or facility is not the operating or controlling employer. This has been an issue in the past, so this addition to Subpart AA will help to clarify which party is accountable and responsible for confined space entry.

As I mentioned earlier, much of the 1910.146 general industry standard is nearly identical to 1926 Subpart AA, but OSHA has added much more detail to many of the paragraphs included in Subpart AA. One example can be found in 1926.1203(e)(2)(vi). The last two sentences of the paragraph read as follows: “All monitoring must ensure that the continuous forced air ventilation is preventing the accumulation of a hazardous atmosphere. Any employee who enters the space, or that employee’s authorized representative, must be provided with an opportunity to observe the testing required by this paragraph (e)(2)(vi).” This enhances the employee’s responsibility to know what is actually in the standard and understand the hazards associated with entry.

Another significant clarification is found in 1926.1203(h)(2), which states that before operations begin, the controlling contractor must obtain information from the host employer about site-specific hazards, including precautions that the host employer, controlling contractor or other entry employers implemented for the protection of employees in the permit spaces. The intent of this rule is to promote better coordination of multiemployer work sites. Much of this language comes from OSHA’s Multi-Employer Citation Policy. It was expanded to be more inclusive and follow the information transfer rule now found at 1910.269(a)(3).

Other Important Differences
I want to point out a few other important differences between 1926 Subpart AA and the general industry standard. First, the terms “lockout” and “tagout” found in 1910.146 are expanded upon and required in Subpart AA. Control of hazardous energy is expected to be performed by the employer, but while that is only implied in 1910.146 when working in confined spaces, it is specifically mentioned in 1926.1202, “Definitions.”

With regard to training, 1926.1207(a) of Subpart AA states that the “employer must provide training to each employee whose work is regulated by this standard, at no cost to the employee, and ensure that the employee possesses the understanding, knowledge, and skills necessary for the safe performance of the duties assigned under this standard. This training must result in an understanding of the hazards in the permit space and the methods used to isolate, control or in other ways protect employees from these hazards, and for those employees not authorized to perform entry rescues, in the dangers of attempting such rescues.” Further, 1926.1207(b)(1) states that the training required by 1926.1207 must be provided to each affected employee in “both a language and vocabulary that the employee can understand.” This is implied in the general industry standard and specifically stated in the construction standard.

Finally, emergency services and rescue rules are very similar in 1910.146 and 1926 Subpart AA. Once again, however, the general industry standard implies that an employer whose employees have been designated to provide permit space rescue and/or emergency services must take the measures listed in 1910.146(k)(2) and supply all necessary equipment and training at no cost to those employees. Subpart AA, on the other hand, specifically requires these actions in 1926.1211(b).

We have reviewed some of the differences and similarities between 1910.146 and 1926 Subpart AA, but in-depth study, training and understanding is required for employers and employees to be in total compliance with OSHA’s rules.

About the Author: Danny Raines, CUSP, safety consultant, distribution and transmission, retired from Georgia Power after 40 years of service and opened Raines Utility Safety Solutions LLC, providing compliance training, risk assessments and safety observation programs. He is also an affiliate instructor at Georgia Tech Research Center OSHA Outreach in Atlanta. For more information, visit

Safety Management, Worksite Safety

Danny Raines, CUSP

Danny Raines, CUSP, is an author, an OSHA-authorized trainer, and a transmission and distribution safety consultant who retired from Georgia Power after 40 years of service and now operates Raines Utility Safety Solutions LLC.