„The testing chamber, and the staff's approach and willingness beyond requirements — I can only recommend them.“
Tomáš Matús
Google review
Surface Degradation Evaluation
In our laboratory we evaluate the degradation of materials, metallic and other surfaces, paints and coating systems before and after stress tests. We assess visible defects, changes in appearance, the extent of damage and signs of corrosion according to customer requirements and the relevant technical standards. The evaluation is particularly suitable after corrosion, climatic, condensation, UV and other exposure tests, when the condition of the surface treatment, the extent of degradation and any failure of the protective or decorative function of the coating need to be objectively documented.
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Over 30 years of experiencein the supply & service of testing technology
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Warranty & post-warranty servicefor our own and competitors' equipment
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Training of your employeesto increase their expertise
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Accredited laboratoriesfor external tests and calibrations
Evaluation of paint and coating degradation according to ČSN EN ISO 4628
The ČSN EN ISO 4628 series of standards is used to evaluate the degradation of the surface of materials, paints and coatings, in particular to classify the quantity and size of defects and the intensity of changes in appearance. In practice it is used to assess changes caused by ageing, weathering, UV radiation, humidity, corrosion or other stress.
The evaluation looks at typical signs of degradation of the surface treatment, such as blistering, rusting, cracking, flaking, chalking, delamination, and corrosion around a scribe or the formation of filiform corrosion. The result is a clear classification of the extent of damage, which helps to compare the resistance of individual coating systems and surfaces.
This evaluation is particularly suitable for:
- coating systems,
- hot-dip and electroplated coatings,
- anodised surfaces,
- powder-coated surfaces,
- metal parts with a protective coating,
- samples after corrosion tests,
- samples after UV and climatic exposure,
- quality control of surface treatments,
- comparison of suppliers, technologies or production batches.
Blistering, rusting, cracking and flaking of coatings
During degradation of the surface treatment a whole range of visible defects can occur. The most common include blistering, the formation of corrosion products, cracking of the coating or its flaking from the substrate.
These defects may signal insufficient surface preparation, unsuitable technology or application conditions, poor compatibility of layers, weak coating adhesion, low vapour permeability and moisture resistance, or an insufficient protective function of the surface treatment against corrosive attack or weathering with UV radiation. Timely laboratory evaluation helps determine the extent of damage and compare the behaviour of different systems after the same exposure.
The evaluation can be carried out, for example, according to these parts of the standard:
- ČSN EN ISO 4628-2 – assessment of the degree of blistering,
- ČSN EN ISO 4628-3 – assessment of the degree of rusting,
- ČSN EN ISO 4628-4 – assessment of the degree of cracking,
- ČSN EN ISO 4628-5 – assessment of the degree of flaking.
Chalking, delamination and corrosion around a scribe
For paints and coating systems, changes that occur after weathering tests with UV radiation and humidity, climatic or corrosion tests are often evaluated as well. A typical example is chalking of the surface, i.e. the formation of a powdery layer due to degradation of the binder.
Evaluation of degradation around a scribe is important especially for protective coatings, where the system's ability to prevent the spread of damage from a defined artificial defect that simulates mechanical damage is assessed. The results help to evaluate the protective function of the coating and compare the resistance of individual surface treatments. A special case of evaluating corrosion at a scribe is filiform corrosion, which occurs especially on non-ferrous substrates such as aluminium alloys.
Applicable parts of the standard:
- ČSN EN ISO 4628-6 – assessment of the degree of chalking by the tape method,
- ČSN EN ISO 4628-8 – assessment of delamination and corrosion around a scribe or other artificial defect,
- ČSN EN ISO 4628-10 – assessment of the degree of filiform corrosion.
Evaluation of samples after corrosion tests according to ČSN EN ISO 10289
The ČSN EN ISO 10289 standard is used to evaluate test samples and products with metallic or other inorganic coatings on a metal substrate after corrosion and other exposure tests. It allows the protective function of the coating and its appearance after exposure to be assessed separately.
In practice, the following are evaluated in particular:
- the extent of corrosion of the base material,
- the condition of the protective coating,
- appearance changes of the surface,
- corrosion products,
- local defects,
- overall functionality and integrity of the surface after the test.
The output can be a protective rating Rp and an appearance rating Ra, supplemented by photo documentation and a verbal comment on the extent of damage.
We'll be happy to advise you.
Ing. Radek Lovětínský
Head of the testing laboratory
What our laboratory offers you
We carry out laboratory evaluation of surface degradation focused on assessing defects of paints, coatings, surfaces and other surface treatments. We evaluate blistering, degree of corrosion, cracking, flaking, chalking, delamination, corrosion around a scribe and filiform corrosion. As a matter of course we also apply standards other than just ISO, in particular according to customer requirements. The tests are suitable for quality control, development of coating systems, comparison of different surface-treatment technologies and validation of products after stress exposure. Most often we evaluate samples after salt spray, condensation tests, cyclic corrosion tests, UV exposure or long-term ageing under combined conditions. Our services also include photo documentation, a verbal description of the damage, classification of the extent of defects, comparison of a reference and an exposed sample, and follow-up microscopic analysis of selected defects. Our standard also includes interpretation of the results with a proposed solution or a statement of conformity with requirements.
Scope of tests
- Evaluation of paint and coating degradation
- Assessment of blistering, corrosion and cracking
- Evaluation of flaking and chalking
- Delamination and corrosion around a scribe
- Filiform corrosion and surface appearance changes
- Evaluation of samples after corrosion tests
What We Test for You
Chalking, delamination and corrosion around a scribe
Evaluation of chalking, delamination, corrosion around a scribe and filiform corrosion serves to assess the degradation and protective function of paints and coating systems after UV, climatic or corrosion tests according to ČSN EN ISO 4628-6, 4628-8 and 4628-10.
Blistering, rusting, cracking and flaking of coatings
Evaluation of blistering, rusting, cracking and flaking of coatings serves to assess visible defects, the extent of degradation and the protective function of surface treatments after exposure according to ČSN EN ISO 4628-2, 4628-3, 4628-4 and 4628-5.
Evaluation of paint and coating degradation according to ISO 4628
Evaluation of paint and coating degradation according to ISO 4628 serves to classify defects and changes in the appearance of surface treatments after ageing, UV, climatic or corrosion exposure and makes it possible to compare the resistance of individual coating systems, technologies, suppliers or production batches.
Which standards we test to
In the field of surface degradation evaluation we work with standards for assessing defects of paints, coatings and surface treatments after stress tests. We assess each order individually according to the type of surface, the material of the product, the coating system and the purpose of the evaluation. We carry out tests for surfaces and surface treatments of industrial products and their parts. If needed, we will help you choose a suitable standard, test procedure or specification for evaluating samples after corrosion, climatic, UV or other exposure tests. Thanks to our competence and flexible scope of accreditation, we also carry out evaluations to standards other than just ISO, according to the customer’s wishes and requirements.
Accredited standards
- ČSN EN ISO 4628-1 – General evaluation of coating degradation
- ČSN EN ISO 4628-2 – Blistering
- ČSN EN ISO 4628-3 – Rusting
- ČSN EN ISO 4628-4 – Cracking
- ČSN EN ISO 4628-5 – Flaking
- ČSN EN ISO 4628-6 – Chalking
- ČSN EN ISO 4628-8 – Delamination and corrosion around a scribe
- ČSN EN ISO 4628-10 – Filiform corrosion
- ČSN EN ISO 10289 – Evaluation of samples after corrosion tests
How Does It All Work?
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Non-binding inquiry
Tell us your testing requirements (e.g. via the inquiry form, email or phone).
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Consultation & requirements specification
We contact you and clarify the test specification and timeline.
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Price quotation
You receive a structured price quotation from us.
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Ordering
After your order we reserve the date and capacity.
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Delivery of samples
You deliver the samples to us in person or by courier.
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Performing the test
We carry out the test on the reserved date.
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Preparing the test report
After the test we send the test report electronically.
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Follow-up support
We'll gladly go through the test results with you.
Words From Our Clients
„JD Dvořák — a company where the impossible does not exist and where it is not only about work. I am glad to have the honour of working with JD Dvořák.“
Libor Pala
TRL Space Systems s.r.o.
„We have worked with JD Dvořák for a long time in testing, the rental of climatic chambers, and the service and calibration of our equipment. We value the helpfulness and professionalism of the department heads and technicians we are in regular contact with during tests and the work carried out. Our technicians also make use of training in various areas of testing, which provides both an expansion of theoretical knowledge and practical demonstrations.“
Jiri Turek
Google review
„What I greatly appreciate is the personal approach to solving every problem. Whether it concerned specific testing requirements or the need for individual consultation, I was always met with willingness and expert help that led to a smooth and efficient collaboration. For me, JD Dvořák is not only a professional company, but also an excellent partner in research and education.“
„We have worked with JD Dvořák since 2020. Since then we have completed several installations together, and throughout they have provided service and the necessary calibrations, always at the highest professional level. They have also helped us with our special requirements and we can always rely on them. Their approach is not only professional and customer-oriented, but also very human, and the cooperation is always pleasant.“
Jan Špaček
Fresenius Kabi Horatev CZ s.r.o.
„Cooperation with JD Dvořák is at an excellent level, as proven by more than 20 years of trouble-free collaboration.“
Libor Šmíd
TÜV SÜD Czech s.r.o.
„You do good work — thank you for the long-term cooperation.“
Ing. Ivan Vavrík
Bel Power Solutions s.r.o.
„Thank you for the professional cooperation so far. You are a very reliable partner for us.“
Ing. Miloslav Mensinger
Škoda Auto a.s.
Test report
This document contains key information about the tested sample and the course of the test. We provide the report in Czech or English according to your needs.
We issue both an accredited and a non-accredited test report according to customer requirements. The type of report is determined by the chosen testing standard.
- Information about the tested sample
- Place and date of the test
- Equipment used and its calibration status
- Description of the test procedure including laboratory conditions
- Graphical record of the test
- Responsible persons
- Photo documentation of samples before and after the test
Why test with us?
Expertise in the field
Not sure how to test your sample? We'll help. We have years of experience and will recommend the most suitable procedure. And if you already know exactly what you want, we'll be your partner — without unnecessary questions.
Flexibility
Our equipment covers most requirements. If something is missing, thanks to our links with manufacturers of testing technology we can often arrange even specialised equipment outside our laboratory.
Reliability & speed
You can rely on both the equipment and our arrangements. We service and calibrate everything ourselves, so we can react quickly and adapt tests to get you results as soon as possible.
Personal approach
Every job is unique to us. We always try to understand your needs and tailor the service exactly to what you expect.
We'll be happy to advise you.
Ing. Radek Lovětínský
Head of the testing laboratory
Frequently Asked Questions
Surface degradation evaluation serves to objectively assess defects and appearance changes of paints, coatings and other surface treatments. It helps determine whether, after exposure, blistering, rusting, cracking, flaking, chalking, delamination or other surface damage has occurred.
The evaluation is particularly suitable after corrosion, climatic, condensation, UV or long-term exposure tests. It is also used for quality control, development of new coating systems, comparison of suppliers or handling complaints.
ČSN EN ISO 4628 is used mainly to evaluate defects and appearance changes of paints and coatings, such as blistering, rusting, cracking, flaking, chalking or delamination. ČSN EN ISO 10289 is used to evaluate metallic and inorganic coatings on a metal substrate after corrosion tests, including protective and appearance rating.
The output is normally a test report with a classification of defects according to the relevant standard and customer requirements, photo documentation, a verbal description of the degradation and a comparison of the reference and exposed sample. We always adapt the scope of the output to the type of surface, the customer's requirements and the purpose of the test.
