Archive: Jun 2023

Sanitary Stainless Steel Piping Systems

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Due to its highly corrosion-resistant nature, the requirement to provide a hygienic environment for both liquids and air service to a process will often involve sanitary stainless steel. The industries that demand a sterile microbiological-free system can be found in Aerospace, Semi-Conductor, Food & Beverage, Pharmaceutical and Personal Care. Some facilities, such as Nuclear and other power generating plants may not have the same need for a biological free environment but require the other benefits found in a sanitary stainless-steel system, such as the durability of the steel.

Sanitary Stainless steel piping systems typically have welded joints with elongated bends and are so designed so that there is a smooth transition from section to section and, therefore, contaminants cannot accumulate. The welds need to be smooth and have full penetration inside and precautions must be made to prevent oxidation during welding. Most Sanitary Stainless-Steel systems use a grade of steel that is either 304 or 316. This type of steel contains Chromium Oxide which protects the sheets or piping components from corrosion or contamination. Welding processes that keep a consistent temperature and exhibit a lower heat input will help maintain the proper amount of Chromium in the steel. Inert gases such as Argon or Helium are commonly used to create this type of welding condition. Orbital welding systems are very precise and reliable due to their speed, consistency and ability to perform most welding in a sterile environment with limited human involvement.

Borescope testing (fiber optics) is frequently required on sanitary stainless steel piping to insure that the interior welds on the piping can be visually seen and confirm that there is a smooth surface with no pits, cracks or areas where contaminants could accumulate. Passivation or pickling can additionally be performed if further hygienic cleaning of the pipe is required.

Discoloration around the welds is often a good indicator of potential corrosion hazards in a sanitary stainless-steel system and should be kept to a minimum or eliminated.

The fabrication and installation of sanitary stainless-steel piping, fittings, valves and equipment requires a contractor’s commitment to extreme quality assurance, proper documentation, verifiable traceability of materials and the ability to provide assistance to the facility during commissioning and start up. Waco has trained welders who are practiced at sanitary stainless steel welding processes. We have a trained QA/ QC staff that keeps updated on current requirements and certifications. We have a quality system in place that streamlines the entire process from design to product delivery.