Posted on: May 27, 2022

Confined Spaces Definition: What Are Confined Spaces?

confined spaces definition

According to the U.S. Department of Labor, roughly 2.1 million workers enter permit-required confined spaces every year on the job. For some, the hazards they encounter inside will be deadly.

In most years, there are between 100 and 150 job-related confined space fatalities. Most are the result of either trench collapse or getting trapped by material in a storage container. Silos and grain bins are especially risky.

The OSHA Confined Space Standard is designed to assess the hazards of a confined space and minimize the risk to people entering those spaces for work. But what does it cover and how does it work?

Confined Space Entry Training for Construction

189 159

Confined Space Entry Training – 8 Hour General Industry

189 159

What Is a Confined Space?

OSHA's confined space definition is a "space that

  • Is large enough and so configured that an employee can bodily enter and perform assigned work; and
  • Has limited or restricted means for entry or exit (for example, tanks, vessels, silos, storage bins, hoppers, vaults, and pits are spaces that may have limited means of entry); and
  • Is not designed for continuous employee occupancy."

In plain language, that's a space that's hard to access and not designed for a person to spend time in but big enough to climb into for work.

Where Can You Find OSHA's Confined Space Standard?

It depends on your industry, as OSHA defines it. There are three:

  • For General industry, §1910.146
  • For Construction, §1926 Subpart AA (effective 2015)
  • For Maritime (specifically, Shipyard), §1915 Subpart B

The general requirements (and goals) are similar across all three, but the Construction and Shipyard standards address unique industry-specific circumstances.

For example, construction work often involves multiple employers per site and a hectic environment, so the Construction confined space standard codifies roles and responsibilities that are simply assumed by the General Industry standard.

The Shipyard confined space standard, on the other hand, is designed to account for the complexity of confined spaces on ships, the presence or proximity to fuel and other combustible materials, and the wide variety of hazardous cargo.

What Does OSHA's Confined Space Standard Require?

Generally speaking, OSHA's confined space standards require employers to:

  • Evaluate for Hazards. If a workplace has an area that meets OSHA's confined space definition, the employer is required to evaluate the space for hazards (and reevaluate when use or configuration changes).
  • Get a Permit If Required. When the employer finds certain circumstances inside the confined space, it becomes a permit-required confined space (sometimes shortened to PRCS or "permit space"). A permit must be acquired before worker entry occurs.
  • Inform Employees at Risk. OSHA requires employers to disclose the existence, location, and danger of any permit-required confined spaces to employees that may be exposed to their hazards with signage. Sufficient training can be used instead of signage.
  • Implement Safety Controls. The necessary controls depend on the hazards of the space, the work being performed, the industry standard being followed, and more. This ranges from barring access to having emergency rescue procedures in place.
  • Train Workers Who Will Enter. Employees need to be trained sufficiently enough to comply with the standards related to their role, work, industry, and the hazards present. They also need to understand

What Makes Something a Permit-Required Confined Space?

Any confined space is inherently risky in that it's hard to get out of and it prevents easy communication with the outside world. When you combine those risks with any hazards that can cause death or serious harm (like the above), then entering the confined space requires extra precautions.

A confined space requires a permit when it has at least one of the following hazards:

  • A hazardous atmosphere (or the potential for it), including
    • Too much or too little oxygen
    • The buildup of flammable or combustible elements in the air
    • The buildup of airborne contaminants that can make you sick
  • A material that can engulf or asphyxiate the entrant, like a liquid and free-flowing solid (such as grain or dirt)
  • A configuration inside that can trap or asphyxiate the entrant, including
    • converging walls or a sloping floor that tapers to a smaller cross-section
    • intrusive pipes, machinery, or other heavy fixed items
  • Any other recognized, serious safety or health hazard

There are many different types of permit-required confined spaces, but here are a few examples:

  • Storage vessels designed to hold liquids, gases, or free-flowing solids
  • Excavations or trenches, which can collapse or flood with little notice
  • Pipes, ducts, flues, or conduits big enough to enter
  • Manholes, access shafts, and wells
  • Cesspools and holding pits
  • Inspection and maintenance pits for heavy machinery
  • Silos and hoppers

What Are Some Examples of Non-Permit Confined Spaces?

When a confined space doesn't meet any of the permit conditions, it's called a non-permit confined space. Examples of non-permit confined spaces include:

  • Ventilated tunnels
  • Drop ceilings
  • Equipment closets
  • Machinery cabinets

As long as someone has assessed the potential for hazards in the space (with the current use and configuration), entry doesn't require special precautions.

Who Must Sign a Confined Space Entry Permit?

The supervisor who originally authorizes entry needs to sign the confined space permit.

But that's just one of the 14 pieces of required information needed on an entry permit. They are the:

  • Confined spaces to be entered
  • Purpose of entry
  • Date and authorized duration of the permit
  • Authorized entrants
  • Names of attendants
  • Authorizing supervisor's name and signature
  • Hazards of the space being entered
  • Measures used to isolate the permit space and eliminate/control hazards before entry
  • Acceptable entry conditions
  • Results of any initial or periodic tests performed, along with when and by whom
  • Rescue and emergency services that can be called on and how to do so
  • Communications procedures used to maintain contact during entry
  • Equipment to be used in the confined space (like PPE, testing or communications equipment, and alarm systems)
  • Any other information related to ensuring employee safety and any additional permits for the work within the permit space

The requirement for a confined space permit ensures that your team has planned things out and considered safety requirements before entry.

Where Can You Get Confined Space Training?

As an OSHA-authorized online training provider, we offer mobile-friendly, self-paced confined space courses for both General Industry and for Construction. You'll learn how to stay safe in a hazardous confined space and the requirements for various aspects of an entry program.

Enroll and get started today!