Have you tried stainless steel piping yet?

We have worked on several projects with a local contractor where stainless steel was used for the ammonia piping system.  One of the most obvious benefits of using stainless steel over carbon steel is the elimination of corrosion.  The use of carbon steel piping presents a challenge to work with, even though it has been the most common piping material in use for ammonia refrigeration systems.

To reduce the potential for corrosion with carbon steel piping it is important to consider pipe coatings.  However, the use of coatings also presents an issue of obtaining a clean pipe surface so that the coating can properly adhere to the pipe itself.  In some instances, sandblasting has been used on the exterior surface of the pipe.  This works well but leaves a lot of abrasive debris behind and increases the need to keep the pipe sealed during the cleaning process.  Pickling of the pipe can also work.  However, either process may eradicate the heat numbers or other distinctive markings which identify the pipe material.

A second consideration is that the pipe must be coated quickly after being cleaned.  In humid environments a light rust may form quickly and defeat the original purpose of cleaning the pipe.

A final thought pertaining to coatings is their application.  Assuming the pipe is properly prepared the use of primer coatings or bonding layers may be required for proper adhesion of the final top coat. In addition, the top coat should be applied to meet the  coating manufacturer’s minimum dry film thickness.

No insulation system is vapor-proof.  Some moisture will eventually find its way into the piping network.  And when it does, the corrosion process may begin.

Using stainless steel piping may also offer benefits of lower roof loads due to weight also.  This may be accomplished by the use of lighter gauge walls.  Depending on construction labor and material total costs, you may find the use of stainless steel piping offers substantial benefits.

If you are using carbon steel pipe, what do you coat the pipe with and what are your surface preparation requirements?

Tags: carbon steel piping, corrosion, insulation, pipe coatings, refrigerant piping, stainless steel piping

This entry was posted on Friday, August 14th, 2009 at 10:40 am and is filed under industrial refrigeration. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.