Accelerated Corrosion Testing (ACT) of external pipeline coatings traditionally has been associated
with the ASTM B117 Salt Fog Test (which is also similar to other standards like the BS3900 Parts
F4 and F12 and the ISO standard 7253). There are other types of ACT for coatings that use “salt
spray” type tests; for example, the acidified salt spray (ASS) and copper acidified salt spray (CASS)
tests, which use test solutions containing acetic acid and copper chloride with acetic acid. Recently,
ACT of coatings has been performed using corrosive gases in a closed environment at constant
temperature and with varying relative humidity (RH). This test resembles the standard ACT for
Electronic Equipment and Devices. The objective of these (sometimes cyclic) tests is to try to mimic
naturally occurring wetting and drying cycles with the addition of a known acceleration factor.
The standard ACT tests are important in the development of new coatings and are commonly used to
qualify new coatings and surface treatments for novel material/environmental applications. Common
practices employ rapid “round robin ACT testing” to down select coating systems from a large number
of candidate systems before proceeding with additional testing (including laboratory testing and/or field
testing). Unfortunately, the standard ACT tests have been shown to inaccurately predict the
performance of coatings in real service conditions. Moreover, utilizing ACT during preliminary robin
testing could lead to inaccurate rankings.
This paper aims to comment on common ACT methods and their accuracy, and to identify those ACT
methods that, with additional development, could more realistically mimic service environments, and
therefore more accurately predict long-term performance. Additionally, this work describes testing on
coatings used for both internal and external coating of pipelines. Of particular interest, the specific
ranking between mechanical testing and corrosion testing will be discussed.
Keywords: Coatings, Coatings Testing, Accelerated Testing, Accelerated Corrosion Testing, Corrosion
Testing, Internal Pipeline Coatings, External Pipeline Coatings, Pipeline(s), EIS