December 2019 SPRAY 29
more than 1–2 containers to increase the likelihood of finding
the deepest pit and thus obtain the best estimation for the actual
pitting rate.
The highest pitting rate found after one year of storage testing
is typically the most accurate estimator for the actual pitting rate
Package service lifetime is the age of
a filled package before it leaks or stops
spraying; it is different from shelf life,
which is considered to be the time when
a specified percentage of the product’s
active ingredients have lost their potency...
and thus the best PSL estimator. Increasing the test temperature
will not provide a quicker or more accurate estimation of
the actual pitting rate for room temperature, nor can data from
higher temperatures be used to shorten the storage test length.
Estimated PSL from pitting data is typically a better pass-fail
criterion than a pass-fail criterion based on visible corrosion/
no visible corrosion. Remember that general corrosion typically does
not lower PSL. Consequently, pitting corrosion depths should be
measured during spray package corrosion examinations.
Pitting rates can also be accurately estimated with electrochemical
test data when the appropriate test parameters and
statistical models are used with the data. Electrochemical test provides
pitting rate data in significantly less time than a storage test.
Please visit www.pairodocspro.com for more information. Thanks
for reading and I’ll see you next year. SPRAY