What is High-Purity ASME BPE Surface Finishing Used for?

The surge in demand for ASME BPE surface finishing for piping and tubing can be attributed to increased high-purity manufacturing. This is primarily because the purity of the final product relies on the purity of the materials used, which, in turn, depend on the systems they pass through.

ASME BPE Standards for Fluid Processing Equipment

In general, ASME BPE standards encompass specifications for designing and constructing fluid processing equipment requiring a specified level of purity control and bioburden management.

These standards cover the materials employed, the methods of design and construction, and the completed system's inspections, testing, and certification.

While the focus is primarily on the surfaces that come into contact with the product or raw materials during manufacturing and storage, these guidelines also extend to other system components involved in the process, such as filtration, clean steam, water for injection (WFI), and sanitization.

Although the finished product may ultimately reside in a tank or vessel, it is worth noting that approximately 90% of the time, fluid products and ingredients interact with surfaces within the piping and fittings. Hence, it becomes crucial to ensure that the interior surfaces of these components do not contribute to fluid contamination.

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ASME Surface Finish Designations: From SF0 to SF6

In line with this objective, ASME has classified seven surface finish levels, each with specific surface preparation and smoothness requirements. These surface finishes are denoted as SF0 through SF6. The smoothness of a surface is determined by its roughness average, commonly referred to as the Ra value.

The following chart provides a comparison of the various SF designations, elucidating the methods through which they are achieved and the corresponding required smoothness levels:

Source: Rodger Industries Inc

What is High-Purity ASME BPE Surface Finishing Used for?

Surface Finish Designation Requirements

The chart reveals that the ascending order of smoothness does not directly correspond to the numerical designation.  

SF0 represents basic piping and is commonly utilized for fluids like compressed air, chilled water, and steam, which do not come into contact with the product. Conversely, SF4 is the smoothest surface designation and is the most used in pharmaceutical applications.

This level of smoothness is attained through a combination of mechanical polishing utilizing power equipment and an electrochemical process that eliminates any remaining surface roughness.  

The Max Ra measurement is pivotal in ensuring that any exceptional measurements, such as the highest peak on the surface, conform to the specified requirements.

Importance of Smooth Surfaces in Piping and Fittings

The primary objective of electropolishing is to achieve an exceptionally smooth surface, preventing the accumulation of fluids or solids. Even a build-up of purified product debris can serve as a starting point for contamination or corrosion.  

Since this can occur within the system without being detected by filtration mechanisms, potential issues may go unnoticed until a product fails.  

A smooth surface facilitates the cleaning of the system by allowing residual substances to be flushed out, reducing the reliance on cleaning agents that may not be compatible with the manufacturing process.

Processing and Installation of High Purity Piping

Remembering that this process is neither a "plug and play" nor a "set it and forget it" approach is crucial. Ensuring that the piping meets the requirements of a high-purity manufacturing process necessitates careful attention before, during, and after construction.  

In some instances, the tubing can undergo off-site processing by the manufacturer, be transported in sealed packaging, and safely installed on-site without compromising the internal purity of the pipe. However, in many instances, the construction or assembly environment can contaminate the tubing's interior as soon as it is unpacked.  

To adhere to the necessary standards, it is customary to electropolish the piping before installation, followed by thorough cleaning and passivation after installation. This comprehensive process involves removing any debris that might have entered during assembly and purging the system of atmospheric pollutants.

Electropolishing before installation guarantees compliance with industry standards, while subsequent cleaning and passivation after installation ensure that the tubing meets the high purity standards required for manufacturing processes.

Benefits of Proper Maintenance, Reduced Downtime and Product Quality

A well-designed system incorporates internal filters and implements a regular schedule for their inspection and replacement throughout its operational lifespan. It is also crucial to establish a scientifically based maintenance plan that includes routine activities such as inspections, cleaning, derouging, and repassivation.

By adhering to such practices, the system's integrity, longevity, and reliability can be upheld, leading to various financial and operational advantages, including extended service life, reduced unplanned downtime, and minimized product spoilage.

Why Adhere to ASME BPE Standards?

To ensure high-purity manufacturing processes, it is paramount to comply with ASME BPE standards for piping and tubing surface finishing.  

These standards delineate surface finish designations that prevent the contribution of contaminants from the interior surfaces of components to the fluid being transported. Pre-installation electropolishing processes guarantee adherence to industry standards.  

Implementing proper maintenance activities, such as inspections, cleaning, derouging, and repassivation, fosters system integrity, longevity, and reliability.

Consequently, this results in decreased occurrences of unplanned downtime and improved product quality. Moreover, designing systems according to the latest ASME BPE standards for high purity offers companies a competitive advantage.

By partnering with reputable industry leaders like Astro Pak, companies can ensure that their systems align with operational objectives. Such collaboration allows businesses to leverage decades of practical experience and best practices.

This information has been sourced, reviewed and adapted from materials provided by Astro Pak Corporation.

For more information on this source, please visit Astro Pak Corporation.


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