What is a Confined Space?

A confined space is a space that is large enough to enter and perform work, not designed for human occupancy, with limited openings for entry and exit.

Permit Evaluation: Permit-Required vs. Non-Permit Confined Spaces

There are two types of confined spaces. Those that require a permit for entry are classified as permit-required confined spaces (PRCS) and those that can be entered without a permit are called non-permit confined spaces (NPCS).

Note for Employers:

 No permit system is required to enter and work in confined spaces. However, similar written operating and rescue procedures are needed. Also, the results of atmospheric testing of the space shall be written and maintained at the work site for all affected employees to review.

What is the difference between permit-required and non-permit confined spaces?

When initially classifying confined spaces, the best approach is to consider every space that has an atmospheric and/or non- atmospheric hazard, or even the potential to contain an atmospheric hazard such as a PRCS. The downgrading of a PRCS to a NPCS can be done only when all hazards have been thoroughly evaluated and eliminated.

A permit-required confined space fits the definition of a confined space and has one or more of the following characteristics:

  • Contains or has a potential to contain a hazardous atmosphere (e.g., paint thinner).
  • Contains a material that has a potential for engulfing the entrant (e.g., liquid, soil).
  • Contains inwardly converging walls or a floor that slopes downward and tapers to a smaller cross-section where an entrant could be trapped or asphyxiated.
  • Contains any other recognized serious safety or health hazard (e.g., unsafe temperature, electrical shock, corrosive chemicals).

A non-permit confined space fits the definition of a confined space but does not contain or have the potential to contain any atmospheric hazard capable of causing death or serious physical harm.

What is the difference in rescue plans?

Because of the speed at which confined space hazards can incapacitate and kill, self-rescue is the preferred plan. The self- rescue plan provides entrants with the best chance of escaping a permit space when hazards are present. Whenever authorized entrants recognize their own symptoms of exposure to danger- or atmosphere, or when a prohibited condition is detected, entrants are still able to escape from the space unaided and as quickly as possible.

Non-entry rescue is the next-best approach when self-rescue is not possible because non-entry rescue can be started right away and prevents additional personnel from being exposed to unidentified and/or un-controlled confined space hazards. Usually, equipment and other rescue aids are employed to assist in removing endangered entrants. In situations where a configuration of the space or other elements prevents the removal of the worker, entry rescue may be the only solution.

Off-Site Rescue If off-site rescue cannot be provided quickly enough, it is not a real option!

  • Remember that while the window of opportunity for a rescue is very brief—only four minutes—the response time for an off-site rescue team may be considerably longer. After four minutes have elapsed, the victim could suffer brain damage or die. In some emergencies, rescuers may have even less than four minutes to act. Other situations may allow more time.
  • Arrange for ahead of time any offsite rescue services and ensure such service can adequately supplement your onsite capabilities. Supply the number and description of each permit-required confined space in the facility ahead of time.
  • Disclose all known hazards associated with space(s) so that appropriate rescue plans can be developed.
  • Provide access to space so that off-site rescue personnel can familiarize themselves with the site, develop a rescue plan in advance, and practice rescue operations.

Common FAQs:

  1. How would I identity Confined Space at a client’s or my facility?

    1. Look for tanks (above or below ground), pits, sumps trenches, clarifiers and some machinery such as furnaces, ovens and mixing vats, to name a few.
  2. What is considered “Entry” into a Confined Space?

    1. Entry is considered the moment any body part breaks the plane to the opening of a confined space. This includes, but is not limited to, hands, feet, arms, legs, and entire body. Therefore, just reaching into a confined space for a tool is considered “entry.”
  3. What are the primary hazards associated with Confined Spaces?

    1. While there are physical hazards associated with confined space, the primary hazard is atmospheric. Due to the nature of confined spaces, there can be a deficiency in oxygen, as well as the presence of toxic, combustible, or flammable properties.
  4. Are there special requirements for workers to wear a respirator?

    1. Yes, an annual fit test for the make and model of respirator for each employee, in addition to medical evaluations, training, and recordkeeping.
    2. An employee is only fit tested to a specific respirator, therefore, they cannot simply use any respirator in sight, unless they are also fit tested for other makes and models.
  5. When entry into a Confined Space is needed, what are the required resources to proceed safely and correctly?

    1. There must be (at a minimum) a three-person crew with a 4-gas air monitor with as much ventilation as possible. The crew must consist of one entrant, one attendant (hole watch) and one confined space supervisor. Additionally, there must be a rescue plan, which usually includes a rescue team.
  6. What is a Permit-Required Confined Space (PRCS) compared to a Non Permit-Required Confined Space (NPCS)?

    1. A PRCS is required when the area contains, or has the potential to contain, a hazardous atmosphere, materials that could engulf an entrant, an internal configuration that could trap or asphyxiate an entrant, or any other recognized serious safety or health hazards.
    2. A NPCS is used when all hazards have been thoroughly evaluated and eliminated.

**HTS treats nearly all Confined Spaces as Permit-Required.

  1. Is a Rescue Plan required?

    1. Yes, a rescue plan is required with realistic options based on the specific situation; every job is different!
  2. How does HTS fit into the picture?

    1. HTS has trained Confined Space entry teams with the proper equipment to safely perform tasks, such as cleaning or hazwaste removal, to maintain compliance and execute the job safely. HTS also staffs trained RESCUE team members and the equipment to perform Horizontal or Vertical rescues.
  3. What are HTS’s capabilities?

    1. HTS can provide stand-by confined space rescue services for our client’s staff while performing an entry. HTS can also provide a confined space entry team to perform work or provide both rescue and entry.

The OSHA website has more information regarding confined space and many other tools you may find helpful. If you have any questions, HTS Environmental Services is also a resource for you. Contact our EHS Department at (562) 906-2633.

Note: The information contained on this page is general in nature and should not be substituted for professional advice.