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Major pharmaceutical company reduces downtimes, improves safety using drone for tank inspections

22 February 2022

Large scale tanks used for manufacturing pharmaceutical products are made out of stainless steel, since it is the best material for cleaning, and they must be kept clean at all times. After each production run the tanks are cleaned with acid and lye.

A production tank at the manufacturing site – Image: Flyability
A production tank at the manufacturing site – Image: Flyability

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But when a plant receives a new tank, or when a new cleaning process is implemented for a tank, health and safety personnel must follow a strict protocol to verify that the tank is completely clean from all foreign contaminants and that future cleanings will be successful.

The protocol requires personnel to spray a fluorescent substance called Riboflavin inside the tank using a long rod, thoroughly coating the sides of the vessel. The Riboflavin sticks to the surfaces inside the tank. After the tank is thoroughly coated, the Riboflavin is then cleaned off in order to show whether the cleaning processes being used are working correctly, and that the CIP (clean in places) protocol will deliver acceptable results in routine operation.

The reason for following this protocol is to test the efficiency of the cleaning process being used in the tanks. Riboflavin essentially acts as a stand-in for potential contaminants, helping personnel to easily see whether their cleaning processes are actually working.

If Riboflavin remains after the first round of cleaning, then the cleaning process must be adapted and the Riboflavin must be re-applied and re-cleaned until the cleaning process succeeds in leaving no more Riboflavin inside the tank.

In general, the protocol requires cleaning personnel to enter the tank twice: 

1. After the Riboflavin has been sprayed within the vessel, to ensure full coverage within the tank.

2. After the Riboflavin has been cleaned off, to ensure that none of it remains within the tank.

Riboflavin on the inside of a tank (left) and an image from the Elios 2 showing trace residue of Riboflavin (right) – Image: Flyability
Riboflavin on the inside of a tank (left) and an image from the Elios 2 showing trace residue of Riboflavin (right) – Image: Flyability

When entering the tank, health and safety workers use UV lights to illuminate the Riboflavin, first to verify full coverage and then to verify that none of the substance is left within the vessel. The entire process is commonly called a Spray Shadow test or a Riboflavin test.

After the test is complete, the company can move forward with using the tank for manufacturing with the confidence that future cleaning steps are working correctly and all parts of the tank can be cleaned.

Customer needs

A major pharmaceutical company owned several large tanks at a manufacturing site located in Austria. The company wanted to explore how new technologies could help make its Riboflavin tests quicker, in order to reduce downtimes and increase savings. It also wanted to see if it was possible to conduct the two verifications required in the cleaning tests – first ensuring full coverage of the Riboflavin, and then ensuring that no more Riboflavin was present after cleaning – remotely, so that workers wouldn’t be required to enter the tanks.

AEROVISION Drone Support, a drone inspection services company based in Austria, proposed testing Flyability’s Elios 2 for the plant’s next round of Riboflavin testing. The drone is designed to fly in confined spaces in order to collect high quality visual data and was therefore deemed suitable to entering the tanks for the tests.


The drone was able to collect all the visual data needed for the two steps of the plant’s Riboflavin tests, conducting tests on five tanks in one day. Using a large screen, visual data from the drone was live-streamed from inside the tank. The operator of the Elios 2 followed the two tank cleaning steps outlined before, but replaced manned entry with drone entry:

The Elios 2’s live-streamed data from inside a tank – Image: Flyability
The Elios 2’s live-streamed data from inside a tank – Image: Flyability

1. After the Riboflavin was sprayed inside a tank, the Elios 2 was flown inside to ensure that the substance had fully covered the interior of the tank. 

2. After the Riboflavin was cleaned off the inside of the tank, the drone again flew inside the tank to ensure that none of the substance remained.

As a result of using drone entry rather than manned entry, an estimated €60,000 was saved by reducing the downtime of the tanks with the time needed for the five Riboflavin tests being reduced from ten hours to just four. Using a drone also meant that no plant personnel were required to enter the tanks and the number of people needed to conduct the tests was reduced from five to just three.

In some instances, the drone did find that not all of the Riboflavin had been fully removed, which meant that a second round of cleaning and tests needed to be done. These findings are fairly common. But when the testing is done manually, they can lead to prolonged downtimes, since a person has to physically enter the tank each time in order to see whether any Riboflavin remains.


Given the success of AEROVISION Drone Support’s test of the Elios 2, the pharmaceutical company said it was interested in using drones more often for the tank inspections it performs as part of its Riboflavin testing.

More tanks are being installed at the plant within the next six months, all of which will require Riboflavin tests, and the company now plans to use drone entry for the spray shadow tests it will need to conduct in the future. The company is also interested in seeing whether UV lights can be attached to the Elios 2, which would enable better visualisation of the fluorescent Riboflavin.

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