Steel Corrosion Assessment & Protection

Completed Steel Corrosion Protection System

For a number of a years, DPA Specialist Consulting Engineers have been at the forefront of the corrosion protection industry. Many currently available anti-corrosion products have been developed through DPA to suit specific application requirements where the more commonly used anti-corrosion coatings systems fail.

Our Industrial Chemists provide an invaluable link between anti-corrosion coatings specifications and application, with their in depth knowledge of the chemistry of such materials enabling our engineers to compile technically superior specifications.

DPA's services in the assessment and protection of structures in terms of corrosion ranges from the investigation of failures to corrosion consultancy, quality surveillance and quality auditing.

DPA's wide range of services include:

Industrial plant surveys: Plants and structures are surveyed in detail in order to assess the corrosive condition of each unit or specific area. Corrosion protection specifications for each afflicted area can then be developed.
Failure investigations: Independent third party investigations of coating failures are undertaken and full reports are prepared, detailing the failure mechanism/s and recommended remedial procedures.
New projects: Excellent corrosion control hinges on an appropriate detailed specification. DPA is in the position to compile all necessary specifications and contract documents for any coatings and corrosion related project.
Chemical resistance: The resistance of coatings materials to a chemical service environment is critical in the specification of appropriate anti-corrosion measures. Our industrial chemists are continuously involved in updating our data base of suitable materials and coatings with respect to resistance to the effects of chemicals. Track records of previous applications are continually maintained as part of the data base.
Corrosion condition assessment: DPA utilises ultrasonic wall thickness testing instruments and pit depth testers so as to ascertain a statistical representation of the corrosion condition of structures. Such data is used in the economical specification of suitable remedials.
Coatings testing: A number of coatings testing techniques are employed by our industrial chemists and technicians in the assessment of coatings suitability. Such tests include accelerated exposure tests where coatings condition is assessed in terms of resistance to a high chloride environment. Quality surveillance and/or quality auditing can be undertaken at a number of levels, depending on the project requirements.
Corrosion Activities undertaken by DPA

Visual inspection: All stages of the coating process are visually inspected. The final film is inspected to ensure that defects such as runs, sags and misses are eliminated.

Surface preparation: Standards of abrasive blast cleaning or mechanical cleaning are compared against the ISO series of visual standards to ensure that the specified standard is achieved.

Surface profile: The peak to valley height of the surface profile is measured with a surface profile gauge and the results are statistically assessed.

Soluble salts: The presence of soluble salts is a common cause of coatings failure and premature corrosion. An indication of the condition of the surface in terms of contamination with soluble salts is obtained by using the well known Weber Reilly solution and assessment charts.

Film thickness testing: Coating thickness is monitored at application stage with wet film gauges and after the coatings have cured, electro-magnetic gauges are used to monitor the dry film thickness of the coating. The results are statistically assessed to ensure that the film thickness falls within the specification tolerances.

Adhesion testing: The adhesion of coatings is tested by means of cross hatch adhesion testing and pull off testing.

Porosity detection: Rogue peaks, entrapped bubbles and low film thicknesses can give rise to a porous film coating. This condition can be detected by measuring the electrical resistance of the film by means of wet sponge and spark testing.

Environmental parameters: It is essential to ensure that environmental parameters including temperature and relative humidity are continuously monitored to ensure successful coatings applications. Cognisance is taken of surface temperatures, due point temperatures and wind velocities. Sophisticated data logging equipment is often used on larger projects where the monitoring of large areas is critical.