Using traditional methods, a boiler inspection is a long process: 3 days for the boiler to cool off; 2 days to install scaffolding, up to 4 days to do the inspection, and another 2 days to remove the scaffolding. And then there is the cost of all that downtime, about $30,000 per day in net profit loss for a typical 500 MW coal plant.
This process requires up to 40 contractors, numerous hazardous man-hours, and a great financial investment; the costs involved with the scaffolding alone can be upwards of $140,000, depending on the size of the boiler.
But energy companies can use drones to cut inspection time 4 days to 1, with no scaffolding required. Hazardous man-hours are drastically reduced and inspections can be completed at a fraction of the cost.
But what does a boiler inspection by drone look like? Where does one begin? Our pilots captured the experience during a recent mission in California.
Before Inspection, Provide Drone Training
You have two options for performing a boiler inspection by drone. You can hire a Drone Services Provider that has experience in boiler inspections (like Measure). Or you can invest in existing personnel to get certified as Part 107 uav pilots. If you have many assets that need maintenance, you may want to invest in cross-application drone training for your internal, licensed pilots. AES did just that and hired Measure to provide the training.
AES pilot training on DJI Phantom Pro 4s in California.
Before heading into the boiler for on-the-job application training, pilots were tested and trained on basic and advanced uav operations.
With a trained staff and/or professional drone pilot, you are ready for inspection day.
Inspection Step 1: Safety Training
As with any inspection, we hold a safety meeting before the inspection to cover all safety precautions and processes. Some topics covered include:
|Operational Risk Assessment||The weather conditions, crew's health, hydration, etc.|
|Crew Coordination & Resource Management||Establish crew member roles during the inspection - who is Pilot-in-Command, Visual Observer (VO), etc.|
|Communication Plan||What are we going to be using to control the drone? How are we going to communicate amongst ourselves (walkie talkies, etc)|
|Navigation & Flight Planning||Where are we going to launch from? Where are we going to land? What flight hazards exist, etc.|
|Battery Life Requirements||Do we have adequate backup batteries? When do we stop to replace the battery?|
|Payload & Research Plan||What data are we trying to compile? What are the metrics we are looking for?|
|Emergencies & System Failures||Just in case, we cover what to do in the case of aborts, loss of control, flyaway procedures, and crew emergencies.|
Inspection Step 2: Suit Up
Even though the boiler has been cooled off from its extremely hot temperatures (up to 1,000 degrees Fahrenheit), it can still get hot and stuffy inside due to limited air circulation. Due to the extreme conditions, heavy gear and fire-resistant clothing is required, including hard hat, safety glasses, steel toe boots, and coveralls.
Measure pilot Matthew Jungnitsch “gearing up.”
It is also extremely helpful to open up all the manholes and support holes a couple days in advance to allow for cooling and air circulation, especially on a hot day.
Inspection Step 3: Lockout Procedure
The lockout procedure is a tricky, but critical part of a safe, successful inspection.
Before the inspection, crews close every valve, disconnect all the fittings, and do everything needed to ensure the boiler is not lit or ignited while people are inside. Each of those valves and fittings are secured with a lock. The keys to those locks are then put inside a box, and the identified Master Key holder puts a lock on that box...and he or she is the only one with the key.
Signing out the keys from the lockout board.
The lockout box.
Andy's got the Master Key.
Nobody can unlock those locks without going through the Master Key holder, which in the case of a drone inspection, will likely be the Pilot-in-Command.
Inspection Step 4: Entering the Boiler Hole
Once everyone is geared up and keyed up, we enter the hole. There is just one hole to get in and out of the boiler, and each crew member must enter one by one.
Before entering the boiler, the Pilot-in-Command goes over last-minute instructions and reviews safety precautions. The goal here is to have as few people inside the boiler as necessary. Due to the harsh conditions, we want to be able to get in, do a thorough and excellent job swiftly, and get out.
Andy, Pilot-in-Command, goes over last minute instructions before going in.
We also have to ensure the drone gets in and out of the boler without harm.
Entering the boiler hole can sometimes be a rather awkward experience. Although the job itself is something we take very seriously, it is nice to have a little lightheartedness when climbing through an opening as if at a playground.
Peering through the portal.
One by one, the crew enters the boiler.
Inspection Step 5: Inspection inside the Boiler
Once the team is inside the boiler, we get the drone up and flying. It is crucial to provide light inside the dark boiler for two reasons:
1. Adequate lighting is critical to getting adequate pictures and providing good data back to the data analysis team.
2. The vision and collision sensors on the drone itself need light to operate effectively. With no light, the drone has an increased chance of crashing.
Hanging floodlights on the boiler walls (not shown in these photos) is highly recommended.
As you can see, it is very dark inside the boiler.
During flight, the drone is inspecting burners, walls, tubes that line the walls, soot blowers, igniters, scanners, temperature probes, and more.
The drone doing its thing inside the boiler.
The whole job can take half a day or a whole day, depending on how big the boiler is.
"Being inside the boiler feels like a movie," Andy Justicia, the Pilot-in-Command, remarks. "With the emptiness of the walls going 150 ft up, it's super clean, which is surprising. It's a surreal experience."
Inspection Step 6: Document Results
In order to properly document the inspection, it is critical to have an engineer familiar with the boiler on site during the inspection. The Pilot-in-Command should take images in a planned and patterned way so that engineers can match the images with the proper parts.
One has to admit that the images captured are mysteriously quite lovely.
Boiler inspection photos taken by the DJI Mavic Pro.
When it comes to boiler inspections, the drone is unequivocally superior to a person trying to see something that requires scaffolding to view. A boiler inspection using drones cuts the inspection time by 75% and completely eliminates the downtime, costs, and hazardous man-hours associated with scaffolding.
When you consider the numbers, the boiler inspection by drone is a no-brainer.