The Importance of Accurate Subsurface As-Builts For OSHA Confined Space Compliance

The Importance of Accurate Subsurface As-Builts For OSHA Confined Space Compliance

One death on a construction site is too many, yet OSHA reported that 951 people died on construction sites in 2021. Thousands more were injured. Many of those injuries, and 10 deaths were due to complications arising from working in confined spaces.

Confined spaces are defined by OSHA as including, but not limited to, tanks, vessels, silos, storage bins, hoppers, vaults, pits, manholes, tunnels, equipment housings, ductwork, pipelines, etc.

While working in a confined space itself may not cause injury or death, the risks workers may encounter while in those tight spaces do.

So, it is crucial to have accurate subsurface and aboveground as-built information for your site that includes the areas surrounding confined space work areas. The ability to immediately find and access that information could be the difference between a life saved and a life lost.

Construction Worker sitting in a crawl space with harnesses attached.
Workers in permit-required confined spaces must be given proper PPE and safety devices to aid in their retrieval

The most common causes of serious injury and death in confined space accidents are caused by the following issues:

  • Oxygen Deprivation
  • Toxic Gasses & Vapors
  • Sudden Release of Liquids and Solids in the Space and/or Toxic Gas Exposure Upon Disturbance/Removal
  • Explosions & Fires
  • Toxic Solid or Liquid Residues
  • Extreme Heat
  • Falling Objects
  • Machinery or Equipment Use or Incorrect Exposure to Machinery
  • Electrocution
  • Poor Visibility
  • Gasses or Hot Substances, or Super-heated Water Pipe Spills

The nature of confined space work often involves welding, painting, chemical use, or flame cutting, all of which increase the risk for the worker.

OSHA’s 621-page ruling – known as Subpart AA of part 1926 of the Code of Federal Regulations – detailing its updated best practices rules for confined space safety is the result of a years-long effort to address these concerns. Safety Directors on construction sites across the U.S. do their best to train their crews and subcontractors on their company’s written safety plans that detail their approved confined space safety measures, but as we all know, individuals sometimes fail to effectively assess risks. That’s when accidents, injuries, and fatalities occur.

So, here’s a quick listing of the best practices laid out in the regulations regarding what they call Permit-Required Confined Spaces.

A Permit-Required Confined Space is defined as posing a serious hazard to human life due to inadequate ventilation and/or toxic air quality. The features of a Permit-Required Confined Space include:

  • A Potential or Actual Hazardous Atmosphere
  • Materials That Could Potentially Engulf a Worker
  • Downward-Sloping Floors or Inward-Converging Walls That Taper into a Smaller Area Wherein a Worker Could Be Trapped and Asphyxiated
  • Unguarded Machinery, Extreme Heat, Fall Hazards, or Other Recognized Health or Safety Risk


When such a space is identified on a jobsite, the employer – usually the general contractor – is required to develop a written program to address the safety issues that complies with OSHA 1926.1203(d).

The employer or GC is required to comply with general requirements like confined space identification & signage, permitting, testing & evaluation, and communications, and to provide retrieval systems that meet OSHA requirements.

They are also required to provide best practice guidance for falls that detail entrance guarding, fall protection gear like restraint lanyards and lifelines, safe access to vertical entrances, backup fall protection equipment, and training.

Providing primary and secondary PPE & training for rescue workers and emergency services also fall under the scope of the employer’s responsibilities, and they must assess the response fitness of any employees who may be involved in a rescue effort.

Each employee is required to receive training and practice simulated rescues annually.

One of the important items noted in Occupational Health & Safety Magazine is the fact that “Non-entry rescue is the preferred and safest means of confined space retrieval and is required unless the retrieval equipment would increase the overall risk of entry.”

Knowing the exact as-built conditions surrounding the confined space – the depths of utility lines, locations of water and sewer pipes, abandoned tanks and lines, and potential secondary entrances – are vital to the retrieval of workers from hazardous confined spaces, whether you are entering to rescue or deploying retrieval equipment prior to a worker entering the space.


Accurate As-Builts Help Reduce Risk for Rescue & Retrieval Efforts in Confined Space Accidents

You want your crews to get home safe every day. So does GPRS. It’s why we do what we do.

That’s why we provide 99.8% accurate imaging and utility locates throughout the U.S., plus millimeter-accurate 3D laser scans of existing conditions, interactive video pipe inspection reporting that provides photo and video of sanitary and storm sewer systems to pinpoint features and defects, and pressurized water line leak detection services. Every GPRS Project Manager is committed to the pursuit of 100% subsurface damage prevention, and their detailed and accurate work on over 500,000 jobs stands as testament to the company’s commitment to safety.

Every GPRS customer receives a complimentary KMZ file and PDF of their utility map, and a SiteMap® Personal subscription, where they can access their utility and other as-built data from anywhere, 24/7, to speed planning, regulatory compliance, and rescue & retrieval efforts.

Learn how your accurate utility data can be available at the touch of a button, here.

Construction worker in crawl space with external harness attached.
External harnesses and lifelines must be attached to mechanical retrieval devices if the confined space is over 5ft. in depth

It’s Been Seven Years. Did OSHA’s Regulation Reduce Confined Space Construction Site Deaths?

The statistics since OSHA reformed its rules surrounding confined spaces in 2015 do not reflect the agency’s hope and expectation to curb confined space deaths to 4% of what they were prior to the new rules and regulations going into effect.

1,030 workers died in the eight years spanning 2011- 2018 from confined space occupational injuries. That’s an average of 129 per year. Two-thirds of the deaths detailed in this period were workers killed while attempting to rescue a team member from a confined space. One might expect that those numbers would have decreased dramatically following the 2015 ruling, but in fact, confined space fatalities soared from a low of 88 in 2012 to 166 in 2017.

OSHA's table shows that accidents and fatalities grew after the initial enactment of its confined space regulations

Data from 2021, however, does indicate a sharp decline to 10 fatalities, which is a 92% decrease, putting OSHA within striking distance of its stated 96% reduction goal. However, outside factors like the pause in business from pandemic and supply chain-related issues likely also played a part in the decrease.

Frequently Asked Questions

What makes a non-permit-required confined space?

As per OSHA’s regulations on confined spaces, “Non-permit confined space means a confined space that does not contain or, with respect to atmospheric hazards, have the potential to contain any hazard capable of causing death or serious physical harm.”

Confined spaces, however, should always be considered more risky than working in normal conditions, and a large factor in construction safety is having accurate utility and concrete as-built information.

Examples of non-permit confined spaces include equipment closets, crawl spaces beneath homes, ventilated tunnels, and drop ceilings.

What is an example of a non-entry rescue?

When you must attempt to extricate a worker from a confined space without anyone else entering the same space, it is considered a non-entry rescue. Safety harnesses affixed with lanyards or lifelines are the most common non-entry rescue PPE for confined space work. It is important to note, however, that any confined space deeper or longer than 5 ft. requires that the retrieval device (lifeline) must be attached to a mechanical device outside the space.

Learn more about GPRS’ commitment to safety, here.