A Systems Application Approach to Corrosion Testing

Moving beyond component testing:

As leaders in the industrial insulation market, we at Johns Manville are committed to thoroughly testing our current products, competitive products, and future product requirements.  We use these tests to evaluate our products for applicability in various situations.  Given the extensive number of applications that require insulation, it is important to stress there is no “one-size-fits-all” product for all applications, and we believe it’s critical to find the product attributes that provide the solution your application requires.

The primary test protocols used to evaluate industrial insulations are almost always publicly available test methods that can be reviewed by anyone.  This allows a fair baseline for any manufacturer, engineer, testing agency, and end-user to evaluate a product.  Many of these tests are test protocols that are formed and detailed by ASTM International, which is a consensus organization made-up of volunteers within a specific industry.

The test methods are developed by an organization, such as ASTM, and referenced in product specifications, data sheets, and contracts.  Such tests are often laboratory scale set-ups that focus on minimizing variation in the test results while still providing accurate behavior of a particular material and its attributes.  Examples of product attributes that are often tested for industrial insulations include thermal conductivity, water vapor sorption uptake, maximum temperature usage, and indicators of corrosion rates.

Recently, test methods that attempt to replicate “real-world” conditions have been developed by outside laboratories, end users, and manufacturers.  Systems, as opposed to individual components, are the new focus in these testing scenarios since everything must work together in these “real-world” applications.  In regard to testing for corrosion potential, pinpointing one source to test is difficult as all components, including jacketing, insulation, coating, installation technique, sealing, and environmental conditions play a role.

System and “real-world” testing results are often difficult to interpret, time consuming, and more complicated than standards addressing laboratory set-ups that focus on examining only one material property.  System tests often have many variables that must be controlled and monitored as much as possible.  That being said, trends and conclusions can often be made if the results are reproducible and show differentiating performance.  By utilizing an independent third-party agency to conduct the testing, manufacturers’ biases can be reduced so that the materials and conditions under analysis and test protocols can be more accurately evaluated.

As part of our on-going focus to understand our products in various applications, we have initiated a testing program at a third-party testing agency to evaluate products and test protocols under accelerated and/or severe CUI (corrosion under insulation) conditions within a system.  The test protocol evaluates the corrosion rate of carbon steel pipes that can be uncoated or applied with a protective CUI coating wrapped with different insulations.  The test set-ups can be submerged in water or dry; exposed to different liquid solutions including chloride water; and cycled between room temperature and 700°F for different periods of time.  The length of time proposed under these conditions is 6 months.

Three different electrochemical analysis test methods are being explored to evaluate corrosion rates and capture a quantitative report of corrosion in the proposed systems. The systems are being analyzed frequently (monthly at a minimum, though usually more often), and post-analysis of the systems will also be conducted to understand the qualitative function of the insulations, coatings, and environmental conditions on the systems.

Over the next few months, the independent lab testing will be completed and analyzed on 6-8 systems using the protocols described above. The data will provide details on the testing protocol as well as results of different insulation materials, coatings, and environmental conditions.  Preliminary results for the different systems look promising and reproducible.  However, until the testing is completed, only a partial picture can be drawn, resulting in all of us waiting for the complete picture.

Assuming that the test methods are approved, we will be able to share new, long-term testing results that can help equip you to better understand corrosion under insulation and how systems work, reducing the impact corrosion has on you, as system operators.