November 2018

Environment and Safety

The benefits of unmanned aerial vehicles in plant inspection services

As the technology surrounding unmanned aerial vehicles (UAVs), or drones (FIG. 1), continues to advance, so too do the ways they are used.

Smith, M., Spitfire Aerial Services

As the technology surrounding unmanned aerial vehicles (UAVs), or drones (FIG. 1), continues to advance, so too do the ways they are used. With drones making an ever-increasing impact in a variety of industries, they are also beginning to make their way into the oil and gas sector, thanks to an increasing number of use cases and a willingness to adopt this new technology. However, to get the most out of unmanned inspections, it is important to understand what drones are capable of and how they can best be used to achieve the greatest benefits possible.

FIG. 1. Due to the many benefits they offer, UAVs are being adopted in many industries, including oil and gas, for inspection, surveying and safety services.
FIG. 1. Due to the many benefits they offer, UAVs are being adopted in many industries, including oil and gas, for inspection, surveying and safety services.

Benefits of using drones.

With the advancements in unmanned vehicle technology, the list of benefits that they can provide continues to grow. To put it simply, unmanned aerial inspections are faster, safer and cheaper than traditional manned inspections.

By utilizing drones for inspection purposes, the need for manned inspections can be greatly reduced, or even eliminated. In many cases, a UAV can identify an indication or defect and capture the data required to determine not only the extent of the finding, but also the kind of repair(s) to be made. If further examination of an indication is needed, the initial aerial inspection has already located exactly where the follow-up manned inspection must be focused.

Drones can also have a positive impact on the safety of plant personnel. In emergency situations, drones can be deployed as a “first responder” to determine if the area is safe and to identify any potential safety hazards. For example, when a wind turbine suffers a catastrophic failure, drones can be used to answer several preliminary questions. These include whether it is safe to send a technician up the tower; if any potential safety hazards exist that technicians should be aware of; if, in the case of a fire, the automatic extinguisher deployed correctly; and if the cause and point of origin can be identified.

Another benefit to utilizing unmanned inspections is the speed at which inspections can be performed. After the team is onsite, the craft can be in the air to begin an inspection within minutes. Manned inspections may require additional equipment, the deployment of bucket trucks, and the planning and rigging for climbing and/or rappelling. After an inspection is completed and the craft has landed, the raw data can then be copied onsite and delivered to decision-makers immediately, allowing site personnel to obtain critical information on any potentially severe indications as soon as they are identified.

The third primary benefit is reduced cost. Reducing the time it takes to mobilize and complete an inspection, and decreasing the need for any additional equipment, translates into direct savings from the cost of the inspection. Since the inspection is not manned, the facility will not need to halt operations while the work is being performed, which helps avoid reductions in output. In addition, potential savings can be found in the avoidance of unrealized costs. The data collected by a UAV is of equal or better quality than the data collected by manned inspections. Rather than collecting one or two images of an indication and writing a report, an inspection performed by a drone will collect dozens of images from a variety of angles that can be analyzed by more than just one individual. The digital nature of the data also allows for easy historical comparison and analysis, which can result in additional insights, such as the speed at which similar defects will worsen, the likelihood of defect reoccurrence and other potential problem areas for that type of defect.

FIG. 2. By utilizing drones for inspection purposes, the need for manned inspections can be greatly reduced or even eliminated.
FIG. 2. By utilizing drones for inspection purposes, the need for manned inspections can be greatly reduced or even eliminated.

Applications of UAVs.

Some of the most common uses of UAVs are for the inspections of columns and flare stacks, pipes and pipe racks, storage tanks and environmental ponds (FIG. 2). However, drones are also capable of performing site surveys, and can provide benefits in lay-down yards and material management. Since drones are capable of performing both visual and infrared inspections, their uses can vary tremendously.

When focusing on inspection applications, some of the indications and defects that can be detected include corrosion, cracks, spillage, leaks and malfunctioning hardware (e.g., nuts, bolts, brackets and seals). Weld inspections are also becoming more common as camera payloads for UAVs become more advanced. Due to the ease of historical comparison and analysis, important insights into safety issues such as corrosion vulnerability, rates of corrosion, hotspots for cracks and estimated rates of crack propagation are becoming easier to obtain.

With advancements in GPS technology, photogrammetry has also become a useful tool for applications such as site surveys and material management. Some UAVs are capable of capturing data that can be used to make topographic maps and generate 3D models in which accurate distance, area and volumetric calculations can be made. These 3D models can also be exported and used in computer-aided drafting programs for renovation and/or expansion planning and design.

Autonomy.

Autonomous flights are performed by using designated flight paths set by the pilot, and points of interest can be created to instruct the craft to capture imagery and/or record videos during flight. One common use of autonomous missions is for the assessment of construction progress. By being able to consistently fly the same path and capture the same images on separate deployments, tracking the progress of a construction project can be done by not only analyzing the captured imagery, but also by using photogrammetry to generate 3D models from the collected data. However, while autonomy is the primary focus of many top drone manufacturers, the technology does not meet many of the current expectations. It is important to understand what drones are, and are not, capable of so that reasonable expectations can be set.

Most commercial UAV platforms on the market carry GPS systems that can complete autonomous missions successfully, but the quality of the collected data does not always meet the standards required for a meaningful inspection. These autonomous flights are not a viable option for more advanced inspections and applications, such as weld inspections, or uses in small and complex environments. The GPS systems being used by drones can keep the craft in the same location with a tolerance of approximately 6 in. in any direction, but that tolerance can be greater in harsher environments (e.g., high winds). For more advanced inspections, 6 in. can greatly impact the success or failure of a mission. For example, being 6 in. farther away from a weld being inspected can result in data that is insufficient for an accurate analysis. In more complex environments, 6 in. can also be the difference between a successful flight and an impact resulting in a crash.

One of the most important factors regarding autonomy is that there will still always need to be someone overseeing the operation. First, in the US, it is required by the Federal Aviation Administration (FAA) that a licensed pilot is present for all commercial UAV operations, including autonomous flights. Second, and more importantly, the pilot can abandon a mission and take manual control of the craft if something goes wrong. This is particularly important when factors out of the pilot’s control affect the safety of the craft or of other individuals. If wind speed or direction suddenly changes, the pilot may need to take control of the craft to avoid a collision. If another aircraft enters the surrounding airspace, the pilot may need to move the drone out of its flight path.

Navigating the market.

As the popularity and availability of drones have increased, the unmanned inspection market has become extremely saturated with people buying drones from their local electronics store and thinking that this off-the-shelf equipment is all they need. However, among other critical technical criteria, unmanned aerial inspections should always be performed by a team of at least two professional individuals, including a pilot and an inspector. Determining which companies are capable and qualified to provide this service (and which companies are not) can be difficult, but two primary factors should always be considered when deciding which company is best:

The platform. With the number of drone manufacturers increasing, the variety of different drone platforms can seem overwhelming. However, the first thing to know is that, if a drone can be purchased from a store shelf, it will (most likely) be unsuitable for performing inspections. The technical specifications and capabilities of such a craft will not only be well below the standards needed to gather meaningful data, but these platforms can also become hazards to safety rather than a tool to improve it.

One primary issue with many of the store-bought platforms lies in the onboard GPS systems. Due to their size and payload capacities, these lower-end drones cannot carry the robust systems that high-end platforms can, and a sudden weak or lost GPS signal can result in the pilot losing control of the craft altogether. On a similar note, the batteries must be smaller and lighter, which means that they will not include the additional components required to make them intrinsically safe. Older platforms will also experience these same issues due to the limitations of the technology at the time of their development. Some people will try to convince you that these issues have been remedied by installing aftermarket upgrades, but many of the current systems that have solved these issues are incompatible with platforms released prior to 2017.

Another platform-based factor that cannot be ignored is the camera system that will be used. The smaller and cheaper drones will only have one camera payload option, but the more advanced systems will have a variety of different compatible options to choose from that will vary greatly in their capabilities. Before hiring someone to perform inspection work, it is highly recommended to look at sample images and data collected, and to know the conditions in which that data was collected. At a minimum, any inspection data should be captured at HD quality—known as 1080P. For more detail-intensive inspections (e.g., weld inspections), the minimum should be Ultra HD—known as 4K.

Certifications and experience. The second primary factor to consider when navigating the market is the personnel that will be performing the inspection(s). Every commercial UAV pilot is required by the FAA to have a Part 107 UAV operator’s license (FIG. 3). However, it is important to know how the collected data will be analyzed. Does the inspector have any certifications regarding inspection or conditional assessment? Will the inspector be the only person analyzing all the data, or will the inspector just be signing the reports? If the latter, do the persons analyzing the data and writing the reports have any certifications? These are important questions to consider, as many drone companies do not come from inspection backgrounds.

FIG. 3. The FAA requires that all commercial UAV pilots have a Part 107 UAV operator’s license.
FIG. 3. The FAA requires that all commercial UAV pilots have a Part 107 UAV operator’s license.

Another personnel-related factor to consider is the experience of not only the company, but also the experience of the personnel who will be working on your site. The most important thing to consider in this regard is the number of flight hours the pilot has and the circumstances under which those flight hours were earned. Pilots may have an impressive log of flight hours that were earned in open fields and low winds, but that does not mean they can fly in small, complex environments under high pressure. In addition, it is also important to note what drone platform those flight hours were earned on. Every platform will behave and handle differently, and it is essential that the pilot has experience flying the platform that he or she will be operating on your site.

To a lesser extent, the inspectors’ experience is important and should also be considered. However, it does not necessarily have to be a deal breaker if the inspectors have a lack of experience when it comes to the work that they have been hired to do. Because the data collected is completely digital, you should acquire a copy of every image that is taken and every video that is recorded. By doing so, you can not only do your own analysis, but you also have the option of seeking out independent analysis and assessments from a more experienced party. While having an experienced inspector does have its advantages, having an experienced pilot should be the top-priority decision.

Takeaway.

As drone technology is advanced and improved upon, the number of applications for, and benefits of, utilizing UAVs will continue to rise. New and improved systems will widen the speed, safety and cost gaps that separate manned inspections from unmanned inspections. The sooner your facilities can implement these new methods, the quicker these benefits will take effect. However, unless the right selection and vetting processes are put into place, the advantages of utilizing unmanned inspections can quickly become disadvantages and liabilities. HP

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