SYSTEM CLEANLINESS Part 2
Copyright REDOX 2002
The preservation process of piping for your system is critical in keeping rust from forming
during the installation process. Under ASTM D4174 Section 7,1.2. it calls for a Vapor Space
Inhibiting oil on the wetted surface of all components including pipe. Normal pickled pipe
usually comes with a heavy AW 46 type oil as a preservative. This does not meet the standards
but actually facilitates the formation of rust. The axiom that water and oil do not mix is
true here. As the pipe is dried in the final stages of the pickling process there always remains
a thin layer of water on the ID of the pipe. Using non-VSI oil gives an initial protection
that may last up to a few hours. After that the water acts as a lubricant allowing the oil
film to slide to the bottom of the pipe. This process can be witnessed when removing the plugs
from the pipe and seeing the milky oil and water pour out. Now, not only are the walls of
the pipe bare and unprotected, but water in the bottom of the pipe and oil are forming chemical
reactions that lead to more rust.
In adhering to ASTM D4174 Section 7.1.2. the piping will store better during the installation
phase because the VSI oil is always emitting a small amount of vapor to continually protect
the pipe. Additionally, REDOX VSI oils have one other unique attribute--they are hydrophobic
and thus lift water out of the grain of the metal thus eliminating the oil and water problems
associated with pickled pipe.
In installations where the piping will take more than a few days to install, the cost savings
in not having to try and flush out rust from pickled pipe will save tens of thousands of dollars
in unnecessary flushing and give a superior operating system.
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