OSHA Confined Spaces Requirements | CO2Meter.com
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OSHA Confined Spaces Requirements

confined spaces osha 

A confined space is any enclosed space with limited entry and exit access. Because of the possibility of harmful gasses, OSHA has created safety standards for workers who access confined spaces.

Table of Contents

What is OSHA's definition of a Confined Space?

Examples of Confined Spaces

OSHA Confined Space Air Monitoring Requirements

OSHA Regulatory and Recommended Limits for CO2

Why are OSHA Confined Space Standards and Training Important?

Atmospheric Monitoring in Confined Spaces

Confined Space Equipment and Monitoring

Additional Resources

What is OSHA's definition of a Confined Space?

In the gas detection world we rely on the Occupational Safety and Health Administration (OSHA)  when referencing required workplace safety standards, assessments, and guidelines. In the US, OSHA ensures safe and healthful working conditions for workers by setting and enforcing standards.

According to OSHA, a confined space is defined as the following:

  1. A space large enough to enter in and work
  2. A space which holds limited opening for entry and exit
  3. A space not designed for continual worker occupancy

A confined space must meet ANY or ALL of the above criteria to be designated a confined space. Examples include freezers, underground pits, sewers or wells, tunnels, tanks, chimneys, grain silos, or commercial freezers.

For example, even if a worker enters and exits a beer cooler several times a day, because it only has one door to enter and exit it is defined as a confined space.

OSHA also defines two different types of confined spaces:

  1. Non-permit confined spaces
  2. Permit-confined spaces

Non-Permit Confined Spaces

Non-permit confined spaces are defined as spaces that do not have a hazardous atmosphere, cannot engulf an individual or asphyxiate upon entry, does not hold internal configuration hazards, and does not contain any recognizable hazard. Using our example above, a beer cooler would be classified as a non-permit confined space.

Permit Confined Spaces

Permit-required confined spaces are defined as a confined space that has one or more of the following criteria:

  1. Contains, or has the potential to contain a hazardous atmosphere
  2. Contains material that can have the potential to engulf an individual/entrant
  3. Has walls that converge inward, or floors that slope downward and taper into a small restricted area that could asphyxiate or trap an entrant
  4. Contains any other recognized safety or health hazards
  5. Is large enough and configured that an employee can bodily enter and perform assigned work
  6. Has limited or restricted means for entry or exit (ex., tanks, silos, keg coolers, storage bins, vaults, and pits)
  7. Is not designed for continuous employee occupancy

The Code of Federal Regulations created 29 CFR 1910.146 for OSHA. 29 CFR was written to place an affirmative duty on employers to train their employees and staff who work in or enter any confined space locations. The code also places a particular emphasis on employers and staff to be aware of the potential hazards, recognize the precautions to take, and be knowledgeable about protective equipment needed to safely perform tasks and duties

Ironically, although OSHA created and actively promotes these standards, many individuals throughout the beverage, brewery, agriculture, and safety industries are unaware of them and lack the knowledge needed to work in and around these hazardous spaces.

Examples of Confined Spaces

  • Oxygen-deficient atmospheres
  • Vaults
  • Condenser Pits
  • Fermenters, Mash Tuns, Silos
  • Indoor Greenhouse or Cultivation Rooms
  • Keg Coolers (Cold Box)
  • Manholes
  • Pipe assemblies
  • Ventilation Ducts
  • Chemical/Water Tanks
  • Sumps
  • Containment Cavities
  • Heat Sinks
  • Electrical Transformers

OSHA Confined Space Air Monitoring Requirements

For those individuals, team members, and staff that are required to enter confined spaces, OSHA has established a list of criteria that must be met and for meeting standards and procedures.

  • A written program must be developed addressing potential hazards and precautions
  • Inform those employees who have not been trained in the standard to keep away during the entry activities
  • Each employee who is involved or has the potential to be involved in confined-space entries must be trained before entering any space
  • Use appropriate signs and barricades to prevent entry from others
  • Identify and evaluate hazards in the permit space, before entry
  • Specification of acceptable entry procedures. This includes having an oxygen content between 19.5 percent and 23.5 percent, LFL of substances below 10 percent and below established PELs, TWAs, and TLVs. – Isolation of the permit space
  • Lockout/Tagout procedures will be followed on all applicable equipment.
  • Indication of specific locking and tagging equipment to prohibit use while the entry is taking place. (Ex: Control or elimination of atmospheric hazards through purging, inerting, flushing or ventilating)
  • Maintenance of appropriate gas detection/ventilation equipment

OSHA Regulatory and Recommended Limits

OSHA Regulatory



OSHA Regulatory


9000 ppm

California Regulatory

TWA 5000 ppm
(ST) 30,000 ppm

OSHA Recommended Short term exposure Limit

30,000 ppm

OSHA Recommended 8-hour TWA

5000 ppm

* PEL - personal exposure limit
* TWA - Time Weighted Average
* ST - Short term

OSHA Page Link

Why are OSHA Confined Space Standards and Training Important?

There are several safety precautions that individuals need to be aware of in their daily work environments, however, confined spaces have continued to be recognized as critical due to the number of deaths and fatalities around confined space and hazardous gas exposure.

According to OSHA, there were 1,030 confined space occupational injuries between 2011 and 2018. Of these, 94 were fatal injuries as the result of inhalation of a harmful gas.

Atmospheric Monitoring in Confined Spaces

Because confined spaces exist and are potentially dangerous there are certain atmospheric monitors and gas detection solutions that have been designed specifically for detecting gas concentrations in hazardous environments. Although individuals working in and around confined spaces often believe they can detect if a hazardous gas is present by smell, there is no other tool that can sense gas concentrations more effectively, quickly, and accurately than a  professionally designed and manufactured gas monitor, detector, or analyzer.

Without proper fixed or portable monitoring in place, individuals can quickly experience overexposure to hazardous gases. Symptoms can include fatigue, headaches, nausea, asphyxiation, and even death from overexposure.

OSHA additionally specifies that "In order to enter any confined space without the use of special types of personal protective equipment or monitoring, such as a self-contained breathing apparatus - atmospheric conditions must have these characteristics:"

  • Oxygen: 19.5 percent to 23.5 percent 
  • Flammability: below 10 percent of the lower flammable limit (LFL) for gases, vapors, mists or combustible dust
  • Toxic gases: below the permissible exposure limit (PEL)/threshold limit value (TLV) or time-weighted average (TWA) of a substance

Should a hazardous space contain higher than allowable gas concentrations, utilizing a proper gas detection monitor is a must and will instantly alert the users that higher concentrations are present by audible and visual indicators.

Confined Space Equipment and Monitoring

In addition to portable safety monitors or wall-mounted safety monitors  confined space equipment includies:

  • Gas-detection equipment
  • Ventilating equipment
  • Proper warning signage
  • Communication equipment (if necessary)
  • PPE to be used when engineering controls such as ventilation equipment is not practical
  • Lighting equipment
  • Barricades to prevent unauthorized entry (Ladders to provide safe access to and egress from the permit space)
  • Rescue and emergency equipment

1. Personal Safety Monitors for Confined Spaces

co2 safety alarm

Portable safety monitors and alarms like the SAN-10 Personal 5% CO2 Safety Monitor or the SAN-20 Personal Low Oxygen Safety Monitor are designed for employees who work in enclosed areas where carbon dioxide or other gas buildup may cause personal harm. In addition, the device also features audible/visual alarm indication, exclusive data logging capabilities, and a man down alarm that can be triggered when an employee fall occurs.

For those looking to detect multiple gas concentrations, we recommend a device like the CM-1000 - Multi-Gas Sampling Data Logger

2. Enclosed Area Safety Monitors

co2 safety alarm

A common gas detection monitoring system that is used throughout beverage, brewing, agriculture, restaurant, and safety industries is the Remote CO2 Storage Safety 3 Alarm. It is designed to detect and alarm for high carbon dioxide concentrations in confined spaces such as fermentation cellars, keg coolers, indoor greenhouses, and mechanical rooms. The device also allows the user to trigger an exhaust fan or send an alert to the fire control panel.

For other enclosed area applications where there is a danger of inert gases displacing oxygen the RAD-0002 Remote Oxygen Depletion Safety Alarm is recommended.

See more products to help you meet OSHA Confined Space Requirements.

Additional Resources

To educate you and your employees on proper confined space guidelines, precautions, and standards the best place to start is the OSHA website. OSHA compliant consultants and training sessions are available online as well.

For an example of a confined space written program template, view this free template by the Brewer's Association Safety Committee.

For more information on confined space and OSHA procedures or additional training, contact us today.

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