OSHA yesterday proposed a rule designed to protect construction industry employees from the hazards resulting from exposure to confined spaces. The agency is accepting public comments on the proposed standard until January 28, 2008.

The proposed rule addresses construction-specific issues and uses a comprehensive, step-by-step approach to confined space safety by defining how to assess the hazards and classify the space. It provides minimum safety and health requirements and procedures to protect employees who work in or near confined spaces, and includes requirements for training, hazard analysis, classification, entering, working, exiting, and rescue.

The proposed standard would require controlling contractors to coordinate confined space operations among a site's multiple employers, regardless of whether or not the controlling contractor has employees in the confined space.

While the agency had issued its general industry confined space rule in 1993, that standard does not apply to construction employers, as it does not specify the appropriate level of employee protection based on the hazards created by construction activities performed in confined spaces.

Under 29 CFR Part 1926 Confined Spaces in Construction; Proposed Rule, employers would first determine whether there is a confined space at a job site and then determine if there are existing or potential hazards in the space. If there are such hazards, the employer then would classify the space according to the physical and atmospheric hazards found in it.

The four classifications are: Isolated-Hazard Confined Space, Controlled-Atmosphere Confined Space, Permit-Required Confined Space, and Continuous System-Permit-Required Confined Space.

The proposed requirements for each type of confined space are tailored to control the different types of hazards.

AContinuous System-Permit-Required Confined Space (CS-PRCS)is a confined space that is a part of, and contiguous with, a larger confined space (such as sewers) that the employer cannot isolate from the larger confined space. It is also subject to a potential hazard release from the larger confined space that would overwhelm personal protective equipment (PPE) and/or hazard controls, resulting in a hazard that is immediately dangerous to life and health (IDLH).

The CS-PRCS classification ensures that the employer recognizes that there are difficulties associated with isolating the hazards of other larger spaces connected to the CS-PRCS, and, therefore, special precautions are necessary, in addition to the other PRCS requirements.

APermit-Required Confined Space (PRCS)is a confined space that has any one of the following: a hazardous atmosphere that ventilation will not reduce to and maintain at a safe level; inwardly converging, sloping or tapering surfaces that could trap or asphyxiate an employee; or an engulfment hazard or other physical hazard.

AControlled-Atmosphere Confined Space (CACS)is a confined space where ventilation alone will control its atmospheric hazards at safe levels. Continuous monitoring is required unless the employer demonstrates that periodic monitoring is sufficient. In a CACS, the atmospheric hazard is controlled but not eliminated. A confined space cannot be classified as a CACS if it has a physical hazard (unless that hazard has been isolated). OSHA believes that the use of CACS measures, as compared with PRCS measures, would be as protective and typically more cost-effective for the employer.

AnIsolated-Hazard Confined Space (IHCS)is a confined space in which the employer has isolated all physical and atmospheric hazards. “Isolated” means the elimination or removal of a physical or atmospheric hazard by preventing its release into a confined space.

This proposed standard does not replace the more hazard-specific construction standards that are already in place, according to OSHA. Rather, it is designed to provide additional protections needed to deal with hazards that may arise when employees are working in or near a confined space.