• Publication Date:
  • Publication Type:
    Final Rule
  • Fed Register #:
  • Standard Number:
  • Title:
    Confined Spaces, Permit-Required


Occupational Safety and Health Administration

29 CFR Part 1910

RIN 1218-AA51

Permit-Required Confined Spaces

AGENCY: Occupational Safety and Health Administration (OSHA), Labor.

ACTION: Final rule; technical amendment.

SUMMARY: On January 14, 1993 at 58 FR 4462, the Occupational Safety and Health Administration (OSHA) published a final rule on Permit-Required Confined Spaces, 29 CFR 1910.146 in the Federal Register. On June 29, 1993 at 58 FR 34844, OSHA published a corrections document for that final rule which contained corrections to the regulatory text and to several appendices of the final rule. This document adds a metric equivalent in paragraph (k)(3)(ii) and further revises the "Atmospheric monitoring" section of appendix E, "Sewer System Entry", of the final rule.

EFFECTIVE DATE: May 19, 1994.

FOR FURTHER INFORMATION CONTACT: Mr. James F. Foster, Occupational Safety and Health Administration, Office of Information and Public Affairs, room N-3647, U.S. Department of Labor, 200 Constitution Avenue NW., Washington, DC 20210, Telephone: (202) 219-8181.

SUPPLEMENTARY INFORMATION: OSHA published its final rule on Permit-Required Confined Spaces, 29 CFR 1910.146, on January 14, 1993 at 58 FR 4462. Corrections to the regulatory text and several appendices were published on June 29, 1993 at 58 FR 34844.

Amendment to 29 CFR 1910.146

The last sentence of 1910.146(k)(3)(ii) requires that a mechanical device be used to retrieve personnel from vertical type permit spaces more than 5 feet deep. OSHA failed to include the metric equivalent of 5 feet in this provision. Since it is the policy of the U.S. Government and OSHA to include metric equivalents of U.S. units wherever possible, OSHA is correcting 1910.146(k)(3)(ii) by adding the metric equivalent (1.52 meters) of 5 feet.

Amendment to Appendix E

In the correction notice of June 29, 1993 (58 FR 34844), OSHA removed all reference to "broad range sensor instruments" from the "Atmospheric monitoring" section of non-mandatory appendix E (see 58 FR 34845) because the Agency felt that it was inappropriate to suggest a particular type of sensor instrument for all sewer entries. However, it appears that, by removing the reference to the broad range sensor, OSHA inadvertently created the impression that the Agency now favored the use of substance-specific sensors over the use of broad range sensors for atmospheric monitoring in sewer systems. This was not the Agency's intent. As stated in the preamble to the final rule, the choice of sensors or other monitoring equipment will, in general, depend on the extent to which the employer has been able to identify the atmospheric hazards present or potentially present in the sewer. Where the employer has already identified those hazards, substance-specific sensors are preferable, because they accurately indicate the concentrations of the identified air contaminants. By contrast, where the employer has not been able to identify the specific atmospheric hazards present or potentially present in the sewer, broad range sensors are preferable because they indicate that the hazardous threshold of a class (or classes) of contaminants (i.e., hydrocarbons) in the sewer have been exceeded.

Sewer permit spaces generally cannot be isolated from adjacent sections of the sewer. This means that air contaminants arising or introduced elsewhere in a sewer system can enter a sewer permit space, without warning, during entry operations. This, in turn, may make it difficult for employers to anticipate the potential atmospheric hazards of a sewer permit space. OSHA expects employers to consider the predictability of sewer permit space's atmosphere when selecting the appropriate equipment for atmospheric testing and monitoring.

Accordingly, OSHA is revising the information in 1910.146, appendix E, pertaining to atmospheric testing and monitoring in sewers. The reference to broad range sensors is restored and the advantages and limitations of both the oxygen sensor/broad range sensor instrument and the substance-specific device are more clearly stated. However, no preference is expressed for either type of meter. Instrument selection is left up to the employer, who is in a position to decide what type of testing instrument is appropriate for a particular sewer entry.

Exemption From Notice and Comment Procedures

With regard to this action, OSHA has determined that it is not required to follow procedures for public notice and comment rulemaking under either section 4 of the Administrative Procedure Act (5 U.S.C. 553) or under section 6(b) of the Occupational Safety and Health Act (29 U.S.C. 655(b)). This action does not affect the substantive requirements or coverage of the standards themselves. This technical amendment does not modify or revoke existing rights or obligations, nor does it establish new ones. This action simply provides additional information on the existing regulatory burden. OSHA, therefore, finds that notice and public procedure are impracticable and unnecessary within the meaning of 5 U.S.C. 553(b)(3)(B). For the same reasons, OSHA also finds that, in accordance with 29 CFR 1911.5, good cause exists for dispensing with the public notice and comment procedures prescribed in section 6(b) of the Occupational Safety and Health Act.

Exemption From Delayed Effective Date Requirement

Under 5 U.S.C. 553, OSHA finds that there is good cause for making this technical amendment effective upon publication in the Federal Register. This technical amendment simply provides additional information on the existing regulatory burden without increasing that burden.

List of Subjects in 29 CFR Part 1910

Confined spaces, Hazardous atmospheres, Monitoring, Occupational safety and health, Safety.

Authority: This document was prepared under the direction of Joseph A. Dear, Assistant Secretary of Labor for Occupational Safety and Health, U.S. Department of Labor, 200 Constitution Avenue, NW., Washington, DC 20210.

Accordingly, 29 CFR 1910.146 is amended as set forth below:

Signed at Washington, DC, this 12th day of May, 1994.

Joseph A. Dear,
Assistant Secretary of Labor.


1. The authority citation for subpart J of part 1910 continues to read as follows:

Authority: Secs. 4, 6, and 8, Occupational Safety and Health Act of 1970, 29 U.S.C. 653, 655, 657; Secretary of Labor's Order No. 12-71 (36 FR 8754), 8-76 (41 FR 25059), 9-83 (48 FR 35736) or 1-90 (55 FR 9033), as applicable.

Sections 1910.141, 1910.142, 1910.145, 1910.146, and 1910.147 also issued under 29 CFR part 1911.

1910.146 [Amended]

2. The last sentence of paragraph (k)(3)(ii) of 1910.146 is amended by adding "(1.52 m)" between the words "feet" and "deep."

3. Section (2), Atmospheric monitoring, of Appendix E of 1910.146 is revised to read as follows:

(2) Atmospheric monitoring. Entrants should be trained in the use of, and be equipped with, atmospheric monitoring equipment which sounds an audible alarm, in addition to its visual readout, whenever one of the following conditions are encountered: Oxygen concentration less than 19.5 percent; flammable gas or vapor at 10 percent or more of the lower flammable limit (LFL); or hydrogen sulfide or carbon monoxide at or above 10 ppm or 35 ppm, respectively, measured as an 8-hour time-weighted average. Atmospheric monitoring equipment needs to be calibrated according to the manufacturer's instructions. The oxygen sensor/broad range sensor is best suited for initial use in situations where the actual or potential contaminants have not been identified, because broad range sensors, unlike substance-specific sensors, enable employers to obtain an overall reading of the hydrocarbons (flammables) present in the space. However, such sensors only indicate that a hazardous threshold of a class of chemicals has been exceeded. They do not measure the levels of contamination of specific substances. Therefore, substance-specific devices, which measure the actual levels of specific substances, are best suited for use where actual and potential contaminants have been identified. The measurements obtained with substance-specific devices are of vital importance to the employer when decisions are made concerning the measures necessary to protect entrants (such as ventilation or personal protective equipment) and the setting and attainment of appropriate entry conditions. However, the sewer environment may suddenly and unpredictably change, and the substance-specific devices may not detect the potentially lethal atmospheric hazards which may enter the sewer environment.

Although OSHA considers the information and guidance provided above to be appropriate and useful in most sewer entry situations, the Agency emphasizes that each employer must consider the unique circumstances, including the predictability of the atmosphere, of the sewer permit spaces in the employer's workplace in preparing for entry. Only the employer can decide, based upon his or her knowledge of, and experience with permit spaces in sewer systems, what the best type of testing instrument may be for any specific entry operation.

The selected testing instrument should be carried and used by the entrant in sewer line work to monitor the atmosphere in the entrant's environment, and in advance of the entrant's direction of movement, to warn the entrant of any deterioration in atmospheric conditions. Where several entrants are working together in the same immediate location, one instrument, used by the lead entrant, is acceptable.

[FR Doc. 94-12088 Filed 5-18-94; 8:45 am]