Inspection and maintenance of steel civil and technological structures are basic activities to ensure their safe and most effective operational life. Requirement/activities of inspection and maintenance are based on implemented Asset Integrity Management, or they can be defined by legislation. For example, in the Czech Republic in accordance with valid development law, the operator/owner is obliged to properly maintain the structure.

The owner/operator of a structure must, according to valid legislation, implement inspection and maintenance activities to ensure the structural and operational integrity of structures. As a clue for these activities they can use the ISO 13822 standard or the Czech ČSN 73 2604 standard. A lot of owners want to increase the operational reliability and maximize service life of their assets beyond legal requirements. To achieve these goals, they want to implement knowledge and procedures from other standards, such as API, EEMUA, ASME, EN, etc.

The cardinal and key method of inspection is visual inspection. This method is also very cost effective in comparison to other NDT methods. Our company provides both variants of visual inspection - direct or remote accordance with the EN 13018 standard. In cooperation with the Drony SIT company we perform indoor remote visual inspection using a special collision resilience drone, the ELIOS 2 from Swiss-based company Flyability. This drone was designed for indoor usage – for access to confined space where there is risk of collision with inspected structures/technology. Remote visual inspection is performed by analysis of image/video captured by 4K camera or thermal camera which is placed on the ELIOS 2 drone.

Process of visual inspections:

  • Inspection of coating degradation
  • Inspection of corrosion level
  • Inspection of completeness of structural elements and their deformations
  • Inspection of structural joints - completeness of bolted joints, welds and rivets
  • Inspection of the integrity of parts of the structure, such as integrity of roof plates

Captured images/videos during remote visual inspection are not the final result of our work. Results are conclusions on what is wrong or not. We always perform assessment of indicated flaws – we design procedures of repair or project other more advanced NDT methods. With our NDT partners we are able to carry out a detailed analysis of the structures.

Flyability ELIOS 2

ELIOS 2 is the second generation of special collision resilience drone for remote visual indoor inspections. This drone is designed for indoor usage which allows access to confined space where there is risk of collision with inspected structures/technology. A good example is a visual inspection of truss girders on roofs. The drone's anti-collision feature is ensured by a protective frame that is resilience to collision up to 5m/s. In comparison with the first ELIOS 1 version, the protective frame no longer rotates around, but is rigid. This is a bit of an advantage because it doesn’t block the cameras’ view. On the drone is a newly mounted ultra HD 4K camera with 3840 x 2160 resolution and a Lepton 3.5 Flir 160 x 120 thermal camera. ELIOS 2 has a new “Distance lock” function that assists a fixed constant distance from the inspected surface. The drone has a modified LED lighting system with an output of 10K lumens that can be partially switched off to adapt the lighting conditions to the inspection needs.