Would you find it hard to believe that a seemingly simple ink marker could be responsible for the jobsite shutdown of two under-construction
nuclear power plants?
Like many industries, such as shipbuilding, military and
aerospace, nuclear power generation utilizes many established
specifications to ensure that the highest levels of safety, quality and performance are being met on that project. So when
it was discovered that the marker being used on the jobsite
wasn’t fully compliant with the specifications for the project,
construction abruptly came to a halt.
Due to the increasingly sensitive nature of these industries,
more and more attention is focused on the materials used in
their construction. Upwards of 90 percent of all jobsites use
multiple types of markers every day for a wide range of applications, yet little time is typically spent considering how those
markers can positively or negatively affect a project.
Whether ink or paint, markers create a permanent mark
by leaving a dye or a mixture of various resins and pigments
directly on the surface of a metal. This direct contact allows
for the interaction of any number of elements or compounds,
some of which can cause gradual to rapid formation of pitting,
intragranular and galvanic corrosion of the material.
Because so many of these industries work with materials
that are required to withstand extreme temperatures, pressures
and materials, any general degradation of those materials can
lead to catastrophic failures. The engineers at these two jobsites
recognized the potential dangers. The safest answer – the only
answer – was to close the sites until a solution could be found.
When Low-Chloride/Low-Halogen Isn’t Enough
The most commonly sought marking products in these
challenging environments are labeled as “Low Chloride” or
“Low Halogen.” Halogens are a group of elements consist-
ing of fluorine, chlorine, bromine, iodine and astatine that,
when in contact with water, form acids. Not only do these
halogens easily bypass the passive films found on materials
like stainless steel, the acids formed can rapidly corrode
the metal with which it comes into contact. Because hal-
ogen, and specifically chlorides, are often highlighted as
being the primary culprits in causing corrosion from mark-
ers, it is easy to assume that they will not lead to unwanted
corrosion of a metal. The fact is that there are many other
chemicals in the ink or paint that have the ability to cause
the same unwanted degradation of the metal, and it is
important to identify these other prominent areas of risk.
Galvanic corrosion is caused when two dissimilar metals
are touching in the presence of an electrolyte. This can
commonly be seen when copper and certain steels come
into contact for long periods of time. Some of the chemicals in inks or paints can be high in certain metals that are
dissimilar to the surface material and can quickly cause the
effect to occur. In addition to these metals, sulfur is one
of the more commonly found compounds that in various
formulations can also cause corrosion, but in a different
manner. When in contact with water or steam, for example,
sulfur can turn it highly acidic, and this reaction intensifies
at temperatures higher than 176 degrees F (80 degrees C).
This acidification can rapidly degrade the metal, weaken
welded components and potentially create any number of
highly dangerous situations.
Many markers labeled as being “Low-Chloride” or
“Low-Halogen” utilize a series of tests to determine the
parts per million (ppm) of the chemicals in the formulation
to determine if they meet levels required to be generally
accepted for use on metals. Because there is no industry
standard for maximum chloride or halogen content, these
can vary by manufacturer, and claims are based upon what
is often called a “typical analysis.”
It is important to note that although these analyses provide
details for both chloride and halogen content, they may not
Low Corrosion Marking:
Is a Low-Chloride/Low-Halogen
Product Enough to Ensure
Safety and Compliance?
By Kevin Talbott
Marketing Manager at LA-CO Industries, Inc.