Confined Space Drone Inspections: The Next Frontier

Introduction

The requirement to inspect confined spaces exists in nearly all industries. However, working in a confined space environment is hazardous. Unfortunately, many workers are injured and killed each year while working in confined spaces in Canada. An estimated 60% of the fatalities have been among the would-be rescuers. A confined space can be more hazardous than regular workspaces for many reasons. To effectively control the risks associated with working in a confined space, a confined space hazard assessment and control program should be implemented for your workplace. All jurisdictions within Canada have strict regulations dealing with confined space entry.

If the confined space cannot be made safe for the worker by taking precautions, then workers should NOT enter the confined space until it is made safe to enter by additional means.  All confined spaces should be considered hazardous unless a competent person has determined otherwise through a risk assessment.

What is a Confined Space?

A confined space is defined as a fully or partially enclosed space that:

• is not primarily designed or intended for continuous human occupancy.
• has limited or restricted entrance or exit, or a configuration that can complicate first aid, rescue, evacuation, or other emergency response activities.
• Can represent a risk for the for the health and safety of anyone who enters, due to one or more of the following factors: (1) its design, construction, location, or atmosphere; (2) the materials or substances in it; (3) work activities being carried in it, or the (4) mechanical, process, and safety hazards present.

Confined spaces exist below or above ground and can be found in almost any workplace. A confined space, despite its name, is not necessarily small. Industrial examples of confined spaces include silos, vats, hoppers, utility vaults, tanks, water supply towers, sewers, pipes, access shafts, truck or rail tank cars, aircraft wings, boilers, manholes, pump stations, digesters, manure pits, storage bins, and culverts. Ditches and trenches may also be a confined space when access or egress is limited. Maritime (cargo) ships, container vessels, and bulk carriers all have numerous confined spaces incorporated into their design and construction. Barges, shipping containers and fish holds are also considered as possible confined spaces.

What are the Hazards in a Confined Space?

All hazards found in a regular workspace can also be found in a confined space. However, these dangers can be even more hazardous in a confined space than in a regular worksite.

Hazards in confined spaces can include:

• Poor air quality: There may be an insufficient amount of oxygen for the worker to breathe. The atmosphere might contain a poisonous substance that could make the worker ill or even cause the worker to lose consciousness. Natural ventilation alone will often not be sufficient to maintain breathable quality air.
• Hazards from asphyxiants: Simple asphyxiants are gases which can become so concentrated that they displace oxygen in the air (normally about 21 percent). Low oxygen levels (19.5 percent or less) can cause symptoms such as rapid breathing, rapid heart rate, clumsiness, emotional upset, and fatigue. As less oxygen becomes available, nausea and vomiting, collapse, convulsions, coma and death can occur. Unconsciousness or death could result within minutes following exposure to a simple asphyxiant. Asphyxiants include argon, nitrogen, or carbon monoxide.
• Chemical exposures due to skin contact or ingestion as well as inhalation of 'bad' air.
• Fire hazard: There may be an explosive/flammable atmosphere due to flammable liquids and gases and combustible dusts which if ignited would lead to fire or explosion.
• Process-related hazards such as residual chemicals, release of contents of a supply line.
• Physical hazards – noise, heat/cold, radiation, vibration, electrical, and inadequate lighting.
• Safety hazards such as moving parts of equipment, structural hazards, engulfment, entanglement, slips, falls.
• Vehicular and pedestrian traffic.
• Shifting or collapse of bulk material.
• Barrier failure resulting in a flood or release of free-flowing solid or liquid.
• Visibility (e.g., smoke particles in air).
• Biological hazards – viruses, bacteria from fecal matter and sludge, fungi, or moulds.

Why is Working in a Confined Space more Hazardous than Working in other Workspaces?

Many factors need to be evaluated when looking for hazards in a confined space, as there is a smaller margin for error. An error in identifying or evaluating potential hazards can have more serious consequences. In some cases, the conditions in a confined space are always extremely hazardous. In other cases, conditions are life threatening under an unusual combination of circumstances. This variability and unpredictability is why the process of hazard and risk identification and assessment is extremely important and must be taken very seriously each and every time one is done.

Some examples include:

• The entrance/exit of the confined space might not allow the worker to get out in time should there be a flood or collapse of free-flowing solid.
• Self-rescue by the worker is more difficult.
• Rescue of the victim is more difficult. The interior configuration of the confined space often does not allow easy movement of people or equipment within it.
• Natural ventilation alone will often not be sufficient to maintain breathable quality air. The interior configuration of the confined space does not allow easy movement of air within it.
• Conditions can change very quickly.
• The space outside the confined space can impact on the conditions inside the confined space and vice versa.
• Work activities may introduce hazards not present initially.
• Lack of communication between the workers in the space, the attendant and the emergency response team.

Statistics of Confined Space Fatalities

In the United States, it has been estimated that about 2.1 million workers enter permit-required confined spaces on an annual basis. According to the U.S. Bureau of Labor Statistics, 1,030 workers died from occupational injuries involving a confined space during the period from 2011 to 2018. The annual figures range from a low of 88 in 2012 to a high of 166 in 2017. The annual number of fatal injuries involving confined spaces for the period from 2011 to 2018 is as follows:

For 643 of these fatal accidents, the most common types of confined spaces resulting in fatal occupational injuries (from 2011 to 2018) are:

Source: Fact Sheet | U.S. Bureau of Labor Statistics | Fatal occupational injuries involving confined spaces | July 2020

Takeaways from the Safety Data

The above data only identifies fatal incidents, not confined-space related injuries, the number of which would obviously be significantly higher than the number of fatalities. Sadly, the number of fatal confined space-related deaths is not decreasing with time. The statistics show that we have not improved mitigating, or eliminating, the risk of confined space injuries and fatalities. In this context, even a single human death or injury in a confined space accident is simply one too many.

The Solution

Drones provide state-of-the-art confined space inspections which are safe, cost-efficient, and time and resource saving, while producing high-quality data. By any metric, the implementation of drones to conduct confined space inspections is a superior alternative to human-based confined space inspections. The next part of our article will examine the use case for drone-based confined space inspections.

The Use Case for Drones in Confined Space Inspections

As noted previously, the requirement for confined space inspections exist in nearly all industries. Stricter regulations, HSE (Health, Safety and Environment) guidelines and ageing assets require increasingly frequent, more thorough, and more complex inspections of elements such as silos, tanks, sewers, pipes, access shafts, chimneys, boilers, manholes or underground cable galleries. Confined space drones, which excel in complex and dangerous confined space environments, are able to easily satisfy these expanded inspection requirements.

Advantages of Confined Space Drone Inspections

1. Enhanced Safety

There is a high degree of inherent risk in confined space inspections. Confined space inspection environments present four (4) primary hazards to human inspectors: 

• Mechanical hazards which include falls, slips, entanglements, entrapment, collapse or falling debris, structural hazards, moving parts of equipment and machinery, and engulfment.
• Insufficient amount of atmospheric oxygen for the inspector to breathe, or exposure to asphyxiants and potentially harmful gases.
• Presence of hazardous chemical or biological substances.
• Risk of fire or explosion.

The above risks to human confined space workers are only mitigated at a high cost in terms of planning, protective equipment, scaffolding, staging, administrative time to apply for and process entry permits, and very often requires an inspection team of at least two (2) people to conduct an inspection.

The primary reason for human inspectors to enter a confined space is to collect visual inspection data. However, specialized confined space inspection drones such as the Flyability Elios 2 can completely replace the need for a human inspector to enter a confined space, collecting visual (and thermal) inspection data that is of such high quality that the human inspector is no longer required to enter the confined space at all. Instead, the human inspector is able to review the inspection data remotely in complete safety.

Regardless of the specific use case, all of the hazards presented to a human confined space inspector can be eliminated by the use of a drone.

2. Return on Investment (ROI) and Cost Savings

Using drones to replace human-conducted confined space inspections can save companies vast amounts of money. Companies can realize these savings in the following ways:

• Elimination of the requirement for scaffolding.  Temporary structures like scaffolding that are used for inspections can be incredibly expensive to put in and take out, sometimes costing tens or even hundreds of thousands of dollars for a single inspection. Using a drone eliminates the need for scaffolding, which represents vast potential savings for companies.
• Reduced asset downtime. Because installing and removing scaffolding is so time-consuming and labour-intensive, using a drone can also mean significantly shorter turnaround times, lessening the loss of potential revenue from having assets offline. In addition, the drone is able to complete the visual inspection in a fraction of the time that human inspector(s) can. Shutdowns are significantly shorter using drones for visual confined space inspections, saving the asset owners from significant lost revenues.
• Lower liability insurance requirements. Because deploying a drone is safer than sending a person into a confined space asset, some companies have been able to reduce their premiums for liability insurance by using drones for confined space inspections.

3. More Frequent Inspections

Because drones represent a relatively inexpensive solution for visual inspections, companies are able to increase the frequency of inspections performed over time, while still realizing significant financial savings over traditional inspections.

More frequent inspections carry the additional benefit of increasing the longevity of a company's assets by detecting defects earlier in the maintenance cycle, allowing them to be repaired long before they become mission-critical and thus requiring forced and extended downtime.

Increasing the frequency of inspections can also help companies to operate their assets longer at peak efficiency levels. This has the collateral benefit of reducing their greenhouse emissions and their carbon footprint in production, thus helping companies to become more environmentally friendly. A recent study by Boiler Room Consulting determined that using drones to conduct boiler inspections could result in the reduction of CO2 emissions by as much as 649 metric tons a year.

4. Defect Location

If a repair team has to dig into the ground or cut into an asset to fix a defect found in a confined space inspection, positional accuracy of the defect becomes very important. A 3D point cloud (digital model) of an asset generated by a drone inspection flight is able to determine the exact location of every defect found in the inspection. Defect localization becomes even more critical in complex assets. This positional information can significantly improve the inspection process by providing a quick way for all parties involved in the maintenance process (inspectors, maintenance crew, site managers, and other stakeholders) to gain accurate knowledge into where repair work may need to be performed.

5. Creation of a Permanent Digital Record of an Asset's Condition

While manual confined space inspections may only produce video and still images of potential defects found during the visual inspection, a drone flight records inspection data (both visual and infrared data) of the entire asset. This visual data provides a historical record of the condition of the asset at a given point in time. Furthermore, this visual data can be used to produce sophisticated 3D models and/or point clouds which can contain even more detail and information about the condition of an asset at a given point in time. This exhaustive quantitative data can assist with investigating the causes of an accident or breakdown, or to accurately track the evolution of a defect’s development. Drone technology enables the creation of permanent digital inspection records, providing companies with a robust historical record of their key assets' condition over time.

6. Improved Access to and within Assets

The Flyability Elios 2 confined space drone is able to navigate entry points as small as 18" (457 mm) in diameter, which allows this drone to access and reach areas where human entry simply is not possible. In addition, even if manned entry into an asset is possible, it may not provide access to key parts of an asset, but a confined space drone like the Elios 2 can often reach otherwise inaccessible areas. Drones have mobility in three dimensions which provides them with the ability to access virtually any place, from any angle, regardless of the shape, material and geometry of the environment. This three-dimensional mobility provides aerial drones with a significant performance advantage over ground or surface-based mobile robotic devices which are restricted to movement in two-dimensions. Finally, drones have significantly greater range when compared to tethered robotic crawlers. Some examples of improved access to assets include:

Sewer inspections. Some sewer systems contain gases that are dangerous to people, or water running at a volume and velocity that is too high for a person to safely enter. If the diameter of the pipe is wide enough, a drone can enter and safely record visual data from a distance, providing visual access to inspection data that wouldn’t be accessible to a person. These challenges can limit manned entry for sewer inspections, and in some cases can prevent a full visual inspection of the entire sewer system.

Wind turbine internal inspections. Inspectors are often limited in how far they can enter a wind turbine to inspect its internal equipment, both by physical constraints to entry and by law. However, a drone can easily circumnavigate these limitations, providing inspectors with more data on the condition of the machinery inside the turbines than would be possible to collect using traditional inspection methods.

Bridge inspections. Some bridges contain spaces that are difficult, if not impossible, for inspectors to access, such as tight areas between beams and box girders. These tight spaces can make bridge inspections challenging for manned entry, and in some cases can prohibit a full visual inspection of the entire bridge from being carried out.

In the above situations, a confined space drone can provide human inspectors with access to tight, inaccessible spaces for the purposes of visual data collection, spaces which would be otherwise impossible to access without a drone.

7. Superior Data

Confined space drones record comprehensive visual and thermal inspection data of an entire asset. They are able to record 4K video as well as capture detailed still images. The inspector is able to save these digital data outputs on a computer and refer to them at a later time to monitor changes to assets over time. Photogrammetry software is able to process this visual data to create sophisticated point clouds (3D models) which contain exhaustive information that can provide a detailed historical record over an asset's lifespan and can be referred to at any given time.

Conclusion

From the benefits of increased safety and efficiency to the quality of data generated, drones represent an ideal means of conducting confined space inspections. Drone technology can revolutionize the confined space inspection process while generating substantial realized savings for your company. Please do not hesitate to contact me for a demonstration of leading-edge confined space drone inspection technology.

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Grayson Lee is a subject matter expert in the industrial application of drone technology. He is director and chief pilot of Digital Content Solutions Inc. Grayson is a Transport Canada Advanced sRPAS pilot, a Transport Canada compliant training provider and flight reviewer, as well as a Pix4Dmapper certified user, a FLIR Level I sUAS thermographer, and a certified confined space drone pilot. He specializes in aerial photogrammetry (mapping) and inspection of critical infrastructure and high-value assets.

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