The Platinum Group Blog

Identify Confined Spaces in Construction Sites and Their Dangers

Written by The Platinum Group | Apr 1, 2025 12:00:00 PM

Construction sites are inherently filled with potential hazards, but confined spaces present unique and often underestimated dangers. Accidents in these areas frequently occur because workers fail to recognize they are operating in a confined space. That’s why confined space identification is the first step in safeguarding workers from injury or fatality.

This comprehensive guide will help you understand what defines a confined space, identify examples on a typical worksite, and recognize when a permit-required confined space applies. Through education and proactive site evaluation, construction professionals can significantly reduce the risk of confined space incidents.

What Is a Confined Space? – OSHA’s Definition

According to Occupational Safety and Health Administration (OSHA) standards, a confined space must meet all three of the following criteria:

  • Size: The area is large enough for workers to enter and perform assigned tasks.
  • Restricted Entry or Exit: The space has limited or restricted means of entry and exit. This doesn't mean there’s only one doorway—it could also refer to difficult access, such as needing a ladder or crawling under low-clearance structures.
  • Non-Continuous Occupancy: The space is not intended for prolonged human occupancy. It may lack adequate ventilation, proper lighting, or enough room for comfortable and safe movement.

These characteristics make confined spaces uniquely hazardous, especially when not marked or communicated to personnel.

Common Examples of Confined Spaces on Construction Sites

Many work environments include areas that naturally meet OSHA’s confined space criteria. Here are typical examples you might find on a job site:

  • Manholes and sewer systems
  • Storm drains and water mains
  • Lift stations
  • Tanks (both aboveground and underground)
  • Basements without stair access
  • Crawlspaces or attics
  • Vessels or silos

Workers entering these areas must be trained and informed about the specific risks and safety measures required to avoid injuries or fatalities.

Permit-Required Confined Spaces: What Qualifies?

While not all confined spaces require a permit, certain added dangers elevate the risk level and necessitate strict control measures. A permit-required confined space (PRCS) includes one or more of the following hazardous conditions:

Hazardous Atmosphere

This includes:

  • Oxygen-deficient environments (less than 19.5%)
  • Oxygen-enriched environments (greater than 23.5%)
  • Flammable gases, vapors, or mists exceeding 10% of their lower explosive limit
  • Toxic gases such as carbon monoxide or hydrogen sulfide

Engulfment Hazards

Materials such as water, sand, or grain that could quickly surround and suffocate an individual.

Entrapment Risks

Spaces with inwardly sloping walls or floors that taper into a narrow area, increasing the risk of workers becoming trapped or suffocated.

Other Serious Hazards


Includes moving machinery, sharp protrusions, electrical risks, venomous animals, or extreme temperatures that could cause harm or death.

If a confined space includes any of these dangers, employers must implement a written permit space program to ensure all hazards are properly controlled before workers enter.

Evaluating Confined Spaces: Best Practices for Safety

Every potential confined space on a job site must be evaluated by a qualified professional. This evaluation determines whether the space meets OSHA’s confined space criteria and if a permit is required for entry.

Key Evaluation Steps Include:

  • Visual inspection of the area
  • Atmospheric testing using calibrated gas detectors
  • Review of blueprints or site layouts
  • Interviews with site engineers and supervisors

It’s essential to remember that each space must be assessed individually. Two similar-looking tanks, for example, may have drastically different hazard profiles based on what materials were stored or what ventilation is available.

Confined Space Entry Procedures and Safety Guidelines

Once a confined space is identified and classified (as either permit-required or not), a proper confined space entry program must be established. This typically includes:

  • Posting signs to clearly mark confined spaces
  • Lockout/tagout procedures to prevent the accidental activation of equipment
  • Atmospheric monitoring before and during entry
  • Ventilation systems ensure breathable air
  • Rescue plans and equipment are readily available in case of emergency
  • Trained personnel, including a designated attendant, supervisor, and entrant

Failure to follow these procedures can lead to severe consequences, including injuries, deaths, OSHA fines, and reputational damage.

Employee Awareness and Training

Your workforce must be trained to recognize confined spaces and understand their responsibilities during entry. Training should include:

  • Confined space identification techniques
  • Permit procedures and hazard communication
  • Proper use of PPE and gas detectors
  • Emergency rescue procedures

Ongoing refresher courses and site-specific training help reinforce awareness and ensure compliance with safety standards.

Prioritize Safety Through Identification and Prevention

Confined spaces are among the most dangerous areas on a construction site—but they don’t have to be. With proper confined space hazard identification, evaluation, and adherence to OSHA standards, these risks can be controlled or eliminated.

Always treat confined spaces with the respect and caution they demand. If you’re ever in doubt about a space, stop and consult your supervisor or a certified safety professional. At the end of the day, your safety is the top priority. Recognizing and respecting confined spaces could be the difference between going home safely and becoming part of a tragic statistic.

To learn more about this potential risk and your Workers' Compensation coverage, make sure to contact a TPG Workers' Comp Specialist at 909.466.7876 today!

Also, learn how Understanding California's Workers’ Comp Mod Factor can help lower your risk and check out these Wildfire Smoke Precautions for Outdoor Workers.