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605 Confined Space Safety
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Confined Spaces in Construction

Introduction

Unlike most general industry worksites, construction worksites are continually evolving, with the number and characteristics of confined spaces changing as work progresses. Multiple contractors and controlling contractors are found more often at construction worksites than at general industry worksites.

A confined space on a construction site.

OSHA's 1926 Subpart AA, Confined Spaces in Construction, standard applies to construction work performed in confined spaces, except for certain construction activities that are subject to confined space provisions in other OSHA construction standards. The activities excluded from this standard are:

  • Diving – regulated by 29 CFR Part 1926 subpart Y.
  • Excavations – regulated by 29 CFR Part 1926 subpart P.
  • Underground Construction, Caissons, Cofferdams and Compressed Air – regulated by 29 CFR Part 1926 subpart S.

Before work begins at a worksite, each employer must ensure that a competent person:

  • identifies all confined spaces in which one or more of the employees it directs may work, and
  • identifies each space that is a permit space, through consideration and evaluation of the elements of that space, including testing as necessary.
  • Maintenance holes (such as sewer, storm drain, electrical, communication, or other utility)
  • Sewers
  • Storm drains
  • Water mains
  • Lift stations
  • Tanks (such as fuel, chemical, water or other liquid, solid or gas)
  • Pits (such as elevator, escalator pump, valve or other equipment)
  • Bins
  • Boilers
  • Incinerators
  • Scrubbers
  • Concrete pier columns
  • Transformer vaults
  • Heating, ventilation, and air conditioning (HVAC) ducts
  • Precast concrete and other pre-formed manhole units
  • Drilled shafts
  • Enclosed beams
  • Vessels
  • Digesters
  • Cesspools
  • Silos
  • Air receivers
  • Sludge gates
  • Air preheaters
  • Transformers
  • Turbines
  • Chillers
  • Bag houses
  • Mixers/reactors
  • Crawl spaces
  • Attics
  • Basements (before steps are installed).

Knowledge Check Choose the best answer for the question.

5-1. Before work begins at a worksite, each employer must ensure that a competent person identifies _____.