The use of unmanned aerial systems to carry out inspections
Drones can be deployed to help decision makers decide on safety and maintenance issues within industrial plants. However their use requires not only new application techniques but also a different approach with regard to work procedures, as well as a detailed understanding of drone technology and how it works; its limitations and potential.
Since the dawn of man, we have looked to the sky and wondered what it would be like to fly with the birds. Then, it was more about the thrill of the flight. Lately it has been more about transportation and civilian progress. Today we live in a world where flying machines do not need to have a human on board, allowing for unimaginable design and uses.
Unmanned Aerial Systems (UAS) or drones are doing everything from delivering medicine in developing countries and providing disaster relief to providing better, safer, and more cost effective infrastructure inspections. UAS’s are benefiting from advancements from cell phones, automotive, gaming and GPS technologies. These developments are running at a mind boggling rate, which create a huge spectrum of operator and equipment capabilities.
UAS lifecycles are running at between six and eighteen months, half that of cell phones. If you were able to see something more often, how would your decisions change? Could you run longer between turnarounds? Would your asset be able to stay in service a few extra years? Would your plant run more safely? To take advantage of the technology, plant leadership and personnel have to think about doing work differently. To do that we have to understand the technology, how it works, its limitations and best applications.
Applications for the use of drones
Let’s start with applications. It is safe to say that anything above your head is an option for UAS inspections. There are three pillars to consider when looking at using UAS: safety, cost/time, and a need for better data. Usually improved safety is a given because you don’t have to put a human at risk. Reduced cost and time usually happens through less scaffolding and rope access, although it may not always be obvious.
An example is pre-turn around preparation. While you many have never used a UAS for turnarounds and may consider it an additional cost, if it saves 2–3 days on a turn-around, overall it is a saving. Lastly, UAS can provide information that was never before obtainable by accessibility or prospective.
Here is a list of applications common today:
- Flares - Stacks
- Tanks (floating and fixed roof)
- Pipe racks
- Construction progress
- Volumetric surveys (secondary tank
- containment, aggregate piles)
- Site mapping (high resolution Google Earth)
- Emergency services
- Internal flying for HRSG/Boilers and tanks
These applications can be found at nearly every plant with ranges in complexity and levels of post-processing. Each one has the potential for significant saving and increased safety.
Limitations when using drones
Limitations are mostly concentrated within the aircraft capabilities and sensors. Aircraft limitations are flight time, wind speed, camera resolution, zoom capability and safety features. One major limitation in the plant environment is Electrically Classified areas or Intrinsically Safe zones (IS).
This is managed by using good sensors with high zoom that can keep the aircraft out of the IS areas while doing the inspection. You should be able to use a UAS that can fly 60+ feet away from the object and still get resolution as if you were standing an arm’s length away.
Here is a list of main considerations:
• Data management
• Operators experience
Not all UAS are built the same. There are personal/recreational grades and there are commercial grades of equipment. A good example is a Cessna 172 and a Boeing airliner. Both are aircraft but with two very different capabilities. The same thing goes for the operator; a pilot with a private license will not have the same capabilities as one with a commercial license.
Make sure you ask about the aircraft to be flown and the experience of the operator. While the aircraft is important to get the sensor to the right location, the sensor is really what brings the value. It is the tool getting you the data from which to make decisions. Many of the sensors carried for inspections today are IR and visual cameras. There are many things to consider with the sensor including weight, zoom, mega pixels, and gimbal to manage targeting and vibration.
You also have to think about management of the sensor while in flight. The functionality to switch from video to photos, manage lighting, and adjust zoom on the fly all help gather the right data, the first time. There are various regulations throughout the world when it comes to using UAS. Generally speaking most Civil Aviation Authorities (CAA) have developed a process for using the technology.
That said, you do have to get approval for commercial operations. CAA’s are mostly interested in ensuring safe operations. They want to know you have a comprehensive operations manual, licensed operators and registered aircraft. Airspace approvals can be a challenge due to the fact that most plants are located in proximity to major airports. While this is not impossible it does take additional coordination with Air Traffic control to ensure safe operations and compliance.
UAS’s are commonly used for internal inspections of HRSG/boilers and tanks.
With cameras taking photos of 8-10 Mb and 4k video, data management is something to consider. The value of the data is that it can be used in a variety of ways. It could be an owner visual with raw images, in a report form or interactive with video goggles. It be stored by the service provider and accessible through the internet or behind the customer firewall. Usually multiple people use the data to manage the asset so putting it in a place that is shareable is important.
As of today there is no standard way to manage it. Integration into day to day operations is critical to realize the advantages of new technology. It is usually a top down and bottom up approach within organizations. In many cases, corporate initiatives to reduce confined
About Aaron Cook
Aaron Cook is the Unmanned Systems Manager at the Mistras Group. He is an ATP rated pilot and the former Director of Aviation at Northwestern Michigan College. Mistras Group is a leader in non-destructive evaluation and embraces robotic technology to reduce elevated and confined space work while increasing value to their customers.