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Quality By Design

One of the cornerstones of our industry is quality; from raw materials to end products, maintaining quality is important. It isn’t important just because supplying a quality product satisfies customers, but also because good quality reduces risk. When you look at a product, like a valve, there are many different aspects to ensuring the quality of the product matches your needs, such as:

  • Material
  • Traceability
  • Material joining (welding)
  • Surface finish
  • Quality assurance

Asepco Tank Bottom Valve, 2 inch

In this article, we look at how ASEPCO specifies and maintains quality. Along the way, we’ll discuss standards, testing, and specifications, and how these items work together to ensure that the quality of the product produced is the highest possible. So, where does this journey begin?

For our products, the journey starts with the established standards we use to ensure that different aspects of quality, such as those in our list above, are achieved and maintained. While there are many different codes and standards that guide the design and fabrication of our valves, such as ASME BPVC, ASME B31.3, and the CE-PED, out primary standard (which you have probably already guessed) is the American Society of Mechanical Engineers Bioprocessing Equipment Standard (ASME BPE).

The ASME BPE standard covers many different aspects of processing equipment and systems to ensure that the equipment can be properly cleaned, sanitized, and sterilized. The list from ASME BPE, GR-2 includes:

  • New system (and component) design and fabrication
  • Definition of system boundaries
  • Specific metallic, polymeric, and elastomeric (such as seals and gaskets) materials of construction
  • Component dimensions and tolerances
  • Surface finishes
  • Materials joining
  • Examinations, inspections, and testing
  • Certification

Designing for Quality

As you can see, this standard influences the quality of our products from the design stage all the way through fabrication and inspection. Before we even begin fabricating equipment, the BPE gives us clear guidance on the requirements our designs must meet. For example, Sealing Components (Part SG) section SG-3 lists the general design requirements for seals—in our case diaphragms and valves. This covers criteria like the service temperature and pressure ranges, as well as making sure that the conditions the diaphragm or valve will be exposed to during use are communicated to the vendor. Compliance with this section ensures that the quality of the diaphragm or valve provides sufficient life for each application it is used in by the customer. Other design requirements within Part SG cover different aspects of design.

SG 3.3.2 focuses on preventing designs from containing crevices or dead spaces that could be potential sources for contamination. For valve design, the criteria in SG-3.3.2.3 are used to ensure that valves are cleanable and sterilizable. SG-3.3.2.3 specifies requirements such as optimizing drainability, requiring process contact surfaces to be easily reached by CIP/SIP fluids, and welding valves into systems to minimize seal use.

Materials

Another key area that influences quality is material specification. Through the requirements of the BPE Standard, we ensure that our material is “…acceptable for use in hygienic service.” When it comes to valves, there are two primary types of materials we need to be concerned about: metallic materials and polymeric materials.

Appropriately, Metallic Materials (Part MM) of the BPE identifies which materials are acceptable for use in hygienic service. This section identifies materials that meet the welding and surface finish criteria listed in the BPE and references other standards that govern other aspects of materials, such as B31.3.

For our diaphragms, SG 3.3 lists the requirements for both biocompatibility and process compatibility. This standard works in conjunction with Polymeric Materials (Part PM). Compliance with this standard helps maintain the quality of the product being produced in the system through biocompatibility testing. It also ensures that the quality of the diaphragm is not affected prematurely by process conditions. Other criteria covered in this section ensure that the surface of the diaphragm is free of imperfections.

Traceability

One of the most critical aspects of quality by design is material traceability. Each lot of metallic material or components with process contact surfaces that we purchase must be supplied with a Material Test Report (MTR). The requirements for MTRs are listed in GR-5.3.1 of General Requirements (Part GR). Among the items listed on an MTR are the material type and the chemical composition of the material. Additionally, the mechanical properties may also be listed.

MTR example
Example of MTR

One reason we maintain this kind of traceability is to make certain that the material we receive is consistent with our customer requirements and industry requirements. The requirements for non-metallic materials, in our case diaphragms, are a little different.

While there is no material test report, there is information required for a Certificate of Compliance (CoC). The requirements for a CoC are listed in GR-5.3.2. Where an MTR includes chemical and mechanical analysis, a CoC confirms the manufacturing lot and the USP testing of the material. For both material types, this kind of traceability is critical to quality, because it proves that the materials are what they should be.

Material Joining

When it comes to fabricating valve bodies, the quality of the material joining (welding the fittings to the valve bodies) is just as important as the quality of the material. While there are specific criteria in the BPE Standard for each type of weld, when it comes to welding fittings to our valves, we use the criteria from Table MJ-8.4-1 (see table below).

Table MJ-8.4-1Table MJ-8.4-1
Table MJ-8.4-1 Discontinuities list

As you can see from the table, there are several criteria that manufacturers need to confirm are within specification to ensure that the weld quality is good enough for use in process. Of course, following welding, in most cases, we then grind the i.d. of the weld to give the valve a uniform surface finish.

Surface Finish

There are two types of criteria that are used to ensure the quality of the process contact surfaces of components:

  • Surface roughness
  • Surface anomalies

Following the BPE requirements for surface finish, such as those defined in Table SF-2.4-1 (below), we ensure that the process contact surfaces of our valves meet the roughness requirements of the Standard.

Table SF-2.4-1
Table SF-2.4-1 Ra readings

To confirm that our valves meet the Ra, as specified by the customer, we measure every part with a calibrated profilometer and include the results of those measurements in the documentation shipped with the order. In addition to surface roughness, we are also aware of any surface anomalies that can cause imperfections on the process contact surfaces of the valve, like those listed in Table SF-2.2-1, below.

Table SF-2.2-1
Table SF-2.2-1 Acceptance Criteria

By meeting surface roughness requirements and eliminating surface anomalies, we ensure that our valves help maintain a systems cleanability and reduce the risk of contamination.

Quality Assurance

Following the BPE, we maintain quality through a quality assurance program (as defined in GR-4) that covers our “…systems, methods, and procedures used to control materials drawings, specifications, fabrication, assembly techniques, and examination/inspection used in the manufacturing of bioprocessing equipment.”

Conclusion

When a product is designed using the ASME BPE Standard, all the areas from design through quality assurance, are employed to ensure that products introduced into the bioprocessing industry—like our valves—are made to a level of quality that ensures a robust life. In turn, this should give users, like you, a level of satisfaction knowing that by using this equipment you can reduce risks in your systems.

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