Introduction to Swiss Approval Thermography Inspection Services
Applications of Infrared, or Thermal Inspection, are very wide, and can range from osmosis on fibers (glass or carbon), to moisture avoidance in houses, passing through surface repairing and coating defects.
Depending on the type of inspection that should be performed, it is very important to guarantee the thermal capabilities of the camera, otherwise the inspection can lead to erroneous considerations.
As a general rule, we can say that small size of defects, requires high thermal and optical capabilities of the camera.
The skill of the operator plays a key role in the inspection, since it is responsible of all the set-up of the camera and the evaluation of the image given.
It is easily understood that the higher the characteristics of the camera, the better the quality of the inspection.
Higher characteristics means thermal sensitivity, which can range from 0,1°C to 0.02°C, depending on sensor dimension, optics and settings. Since infrared inspection is a superficial inspection, in order to perform a complete inspection, it is necessary to combine both superficial and volumetric.
With this combination, a component or a defect, can be completely identified, and the tailored corrective action can be applied.
Volumetric control implies to control the volume of the object. The most common control is by ultrasound or ultrasonic test, which is a contact and non destructive examination. By means of ultrasound it is possible to evaluate thickness's and internal flaws that cannot be reached by infrared inspection. As an example, considering a putty repaired area, infrared inspection tells us the extension of area repaired, but for measure the thickness, ultrasonic testing is required.
All metal parts can be inspected, like propellers, shaft, crank case and basements. Another inspection that can be performed on ship's external coating is the determination of gloss and colour. Gloss is measured by a gloss-meter that by means of reflection of a an emitted light beam, rank the gloss in terms of GU, gloss units, from 0 to 100. Color can be checked with a portable colorimeter or spectrophotometer. The colour is measured according to RAL scale, or custom rating system.
Application in Yachts / Marine
Infrared inspection can be applied easily in yacht because is a non-contact and non-destructive operation and do not alter the characteristics of the equipment and materials to be inspected.
Depending on type of inspection, there are some requirements that has to fulfil. For hull, keel, rudder, propeller, shaft or ventral fins inspection, the ship should be in dry dock.
External coating on hull or structures, can be inspected satisfactorily allowing to identify the most common defects, like blisters, cracks, osmosis, degradation and delamination. It is also possible to identify repaired areas and their condition, since the putty used has different thermal properties from the fiber glass or metal.
Osmosis and blistering Inspection Services
Osmosis is a phenomenon caused by when a fluid with high salt content is separated by a porous media, from a low salt content fluid. In the ship, the high salt content is sea water, and the low content salt is the air. The porous media is aged fiber glass and coating layers. For steel structures, the porous media are the coating layers only, and the low content salt fluid is any bubble of air entrapped during coating. Salinity through the ocean in the world, is not uniform so osmosis can be different depending on the sea. During osmosis the sea water penetrates the coating, and creates some underlayer solid salt accumulation. This salt has different thermal properties of the entire hull, so after thermal exciting, it is possible to identify precisely the area interested.
Fiber Glass condition monitoring services
Fiber glass is a material made of glass flakes, mainly silica, bonded in an epoxy resin matrix. The shape of the object plays an influence on the mechanical properties. When completely cured, the different directions of the flakes, gives an important mechanical resistance which due to shaping flexibility, can be used widely in marine industry. Ageing of the epoxy resin is a process which depends on the environment where the ship operates.
The performance of the engines, regardless if they are electric or combustion, can be monitored with infrared camera. More precisely, if there is some misalignment in the shafts or basement, this vibration will produce an abnormal heating that can be easily seen. It is possible to check the thermal insulation of the motors in order to don't create hot spots inside the ship cabins.
Electrical Installations Inspection Services
Electrical wiring, cabinet, motors can be assessed through a thermal camera. From physics it is known that a current passing through an object produce a heating due to the friction of the electrons. The heat produced a clear image of thermal anomalies.
If in a room there is a specific value of humidity and temperature, moisture can be formed on the wall and in more aggressive form, can create mould. Conditions can be created by any mean, but normally can be found when there is a transition from a hot area to cold area. Mould and moisture, viewed through a infrared camera, are blue because the water have a lower temperature/emissivity of the surrounding wall.
Reporting and Certification of Thermography Inspection Services
Due to complexity and importance of the controls above mentioned, the performing operator should be duly qualified in order to ensure the highest skill and technical advise of the area inspected. The regulating standard for qualification of the operator is ISO 9712. Being qualified by this international standard, requires a previous experience endorsed by Swiss Approval. For coating inspection, Swiss Approval Inspectors are FROSIO or NACE certified, and can perform inspection services of the highest value. Swiss Approval Certified Perosonnel includes UT and Advanced UT Level II experts, in order to execute specific inspection activities on materials and parts. Depending of the nature of service, a Swiss Approval Report or Certificate of Conformity can be issued, after completion of inspection and the related technical review.
Swiss Approval can provide full inspection service, superficial and volumetric, on coatings, mechanical and electrical parts of any construction or ship. Welding inspectors and qualified Welding Engineers, can monitor and inspect any repair or work on steel parts. Our staff is fully qualified and certified according to ISO 9712 for non-destructive examinations, ultrasonic, infrared, liquid penetrant, magnetic particle and x-ray film interpretation. NACE and FROSIO certified coating inspectors can evaluate the condition of the external coating and provide monitoring to tailored repair activities, according customer / project needs.