Does "Subpart AA - Confined Spaces in Construction" Apply to You?

Subpart AA provides the standards for confined spaces in the construction industry. According to the scope, examples of locations where confined spaces may occur include, but are not limited to, the following: Bins; boilers; pits (such as elevator, escalator, pump, valve or other equipment); manholes (such as sewer, storm drain, electrical, communication, or other utility); tanks (such as fuel, chemical, water, or other liquid, solid or gas); incinerators; scrubbers; concrete pier columns; sewers; transformer vaults; heating, ventilation, and air-conditioning (HVAC) ducts; storm drains; water mains; precast concrete and other pre-formed manhole units; drilled shafts; enclosed beams; vessels; digesters; lift stations; cesspools; silos; air receivers; sludge gates; air preheaters; step up transformers; turbines; chillers; bag houses; and/or mixers/reactors. Are your employees engaged in construction activates involving confined spaces? If yes, then this subpart applies to you.

This subpart does not apply to:

  • Construction work regulated by subpart P -  excavations
  • Construction work regulated by subpart S -  underground construction, caissons, cofferdams and compressed air
  • Construction work regulated by subpart Y - commercial diving operations

This subpart provides key definitions applicable to the subpart including the following:

Confined space means a space that:

  • Is large enough and so configured that an employee can bodily enter it;
  • Has limited or restricted means for entry and exit; and
  • Is not designed for continuous employee occupancy.

Permit-required confined space (permit space) means a confined space that has one or more of the following characteristics:

  • Contains or has a potential to contain a hazardous atmosphere;
  • Contains a material that has the potential for engulfing an entrant;
  • Has an internal configuration such that an entrant could be trapped or asphyxiated by inwardly converging walls or by a floor which slopes downward and tapers to a smaller cross section; or
  • Contains any other recognized serious safety or health hazard.

It provides standards regarding the general requirements (i.e., space evaluation, confined space program, procedures, entry communication and coordination), permit-required confined space program requirements (i.e., written permit space program, entry permits, entrants, attendants, testing), permitting process (i.e., canceling permits, completing permits, terminating permits), and entry permit (i.e., purpose of entry, hazards present, entrants, safety measures). It also provides the requirements pertaining to training, duties of authorized entrants, duties of attendants, duties of entry supervisors, and rescue and emergency services. In addition, the subpart requires employee participation (i.e., information available to employee, employee consultation on permit space program) and provision of documents to secretary (i.e., documents need to be available to OSHA).

More information can be found on the A-Z safety and health topics page for confined spaces.