Whether it is the FDA, NASA or some other external agency – many organizations have mandates to ensure that corrosion (rust or rouge) is not present in their product and distribution systems, tanks, vessels or equipment. Therefore, stainless steel systems for water, steam or products must be free of corrosion. Removing corrosion, also referred to as ‘derouging’, is critical for product safety and also extends the life of systems and equipment. Rouge not only can cause surface degradation, but also expose contaminants into the final product. In addition, rouge areas may exacerbate bioburden issues within the system itself causing greater contamination.
What is Rouge?
A general term used to describe a variety of discolorations in high purity stainless steel systems. It is compose of metallic (primarily iron) oxides and/or Hydroxides. Three types of Rouge are as follows:
Type 1 Rouge originates from an external source. It usually appears as a lightly-adhered red or orange “dusting” of the surface. Most Type 1 Rouge is metal oxide particles that are broken loose by erosion of rouge or cavitation at pump impellers or internals. This type of rouge is relatively easy to remove chemically or by electropolishing. Generally, a wipe may or may not remove Rouge Type 1. However, it is best to passivate the surface after Type 1 rouge removal to ensure Rouge removal.
Type 2 Rouge forms at the site where it is seen and where chloride exposure is induced. It typically has a red, reddish-orange, or brownish color. A chemical process removes the rouge or it may need more aggressive derouging formulations or by electropolishing. The surface must be passivated after Type 1 rouge removal.
Type 3 Rouge normally contains a form of iron oxide called magnetite, which is black in color and forms in high temperature steam systems. It often has relatively high silica content in many cases which can make it resistant to chemical removal, necessitating the use of more aggressive chemicals. On shiny surfaces, it may appear tightly adhered and shiny, but on rough surfaces, it is less tightly adhered and may have a powdery appearance. Removal of Type 3 Rouge, includes aggressive chemical solution, or mechanical polishing and/or electropolishing.
Each type of rouge has a specific chemistry and process for remediation. Post derouging, it is imperative to Passivate in order to provide enhanced corrosion resistance.
Trust the Rouge Experts
For over 60 years, Astro Pak has been perfecting the chemistry and cleaning process of passivation and derouging. Our proprietary chemistry, UltraPass® is a chemical treatment for stainless steel and other metals that enhances the ability of the treated surfaces to resist corrosion. It ensures the greatest chrome level on the surface, which in turn yields optimal resistance to future corrosion.
Astro Pak delivers chemical cleaning & passivation services to installed systems: pre-operational, pre-commissioning of new construction, post modification, or for maintenance during shut-downs. Whether it is UltraPass®, nitric acid, or other chemistries, we can process piping, fittings, vessels or other types of equipment. In addition to our expertise in circulating chemistry through facility equipment, tanks, and distribution systems, we also have a Gel Passivation process to address surface discoloration, spot rouge, HAZ of welds, or corrosion on most exterior surfaces. We can perform our work at customer facilities or in one of our nationwide locations.
Astro Pak commits to providing customers with the level of excellence they expect and deserve by:
- Rapid Response
- Highly Trained Personnel delivering superior consulting services
- State of the Art Equipment Nationwide
- Advanced Chemistry & Process Technology
- Superior Documentation (Meeting cGMP Requirements)
We routinely respond to emergency situations for critical utilities, systems and equipment. When our job is complete, you will receive cGMP compliant documentation packages for your systems and equipment maintenance records. Let our experienced and credentialed team of chemists, engineers, and other professionals on staff EXCEED your expectations.
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