Bioprocessing Equipment FAQ « Titan Research Group

Bioprocessing Equipment FAQ

Sanitary Fittings and Tubings Q&A

In support of advance of bioprocessing safety, some common FAQs are addressed in this blog:

    • [wpex more=”What are Sanitary fittings and tubing?” less=”What are Sanitary fittings and tubing?(click to hide)”]Sanitary fittings and tubing, also known as hygienic fittings and tubing and fall under North American ASME Bioprocessing Equipment (BPE) standard, which is listed in ASME B31.3 Process Piping. ASME B31.3 process piping also deals with construction of sanitary tubing systems in Section IX High Purity section.Sanitary fittings and tubing designed to ASME BPE are designed for cleanability whose surface finish and passivation is standardized to limit entrapment areas where bacteria could form or harbor. They are also corrosion resistant when system are cleaned by either dismantling a system and manually cleaning it or using a CIP (clean in place) process. [/wpex]
    • [wpex more=”What are Sanitary fittings and tubing made of?” less=”What are Sanitary fittings and tubing made of?(click to hide)”]Most sanitary fittings are either 304 or 316L stainless steel. More noble alloys such as AL6XN, Titanium and Hastelloy are available in limited quantities and sizes.[/wpex]
    • [wpex more=”What kind of surface finish is required?” less=”What kind of surface finish is required?(click to hide)”]The quality of the surface finish is categorized by its Ra. Ra is the average distance between peaks and valleys on the metal surface. It is normally measured in micro inches. The minimum Ra measurement to render a fitting as “sanitary” is 32. Many industries such as the biopharmaceutical industry require tubing to be the 15-20Ra range.[/wpex]
    • [wpex more=”What are the BPE and 3A sanitary fitting similarities?” less=”What are the BPE and 3A sanitary fitting similarities?(click to hide)”] BPE and 3A fittings are considered sanitary and because both are measured by tube OD they may be welded to one another. The triclamp dimensions for the for the two are also the same. But not all dimensions are consistent between BPE and 3A[/wpex]
    • [wpex more=”What are the BPE and 3A sanitary fitting differences?” less=”What are the BPE and 3A sanitary fitting differences?(click to hide)”] 3A fittings started their use in the dairy industry. They are marked with the 3A to indicate for use in the dairy applications. An ASME subgroup, known as the BPE, developed its own standards for fittings. These fittings needed extended tangents to accommodate the orbital weld heads used heavily in the autogenous welding procedures used in the joining of pharmaceutical fittings. BPE fittings dimension are requirements are outlined in the Bioprocess Equipment standard and are designed to be fully drainable when properly installed.3A and BPE fittings is the availability of lot and material traceable certs. On 304 3A fittings, normally getting heat certificates can be a challenge. BPE fittings, on the other hand, almost never ship without them and often have a QR code on the package that allow a smartphone to almost instantly retrieve the MTR as per the ASME BPE QA requirements.As for materials, 3A fittings are commonly offered in both 304 and 316 stainless steel. BPE fittings are offered exclusively in 316L SS.Regarding surface finish, both 3A and BPE fittings have 32 Ra or better “sanitary” finishes. 3A fittings meet this spec and often exceed it. The standard BPE finish is the #3 PC or SFF1 finish. The #3 finish has a 20 Ra Mechanical ID polish and an unpolished OD. The most common BPE finish is the #7 or PL finish. This is a 20 Ra mechanical ID finish and a 32 Ra polished OD. BPE also offers an electropolish finishes- PL and PM. These finishes feature a 15 Ra ID w/ EP and either polished or unpolished OD’s. Due to the expense of obtaining these finishes, BPE fittings are generally more expensive than 3A fittings.

      As for end styles, BPE fittings are available in exclusively butt weld and hygienic triclamp ends. While 3A offers I line, John Perry, or Q line fittings available in other sanitary fitting styles.[/wpex]

    • [wpex more=”Is sanitary tubing and sanitary piping the same?” less=”Is sanitary tubing and sanitary piping the same?(click to hide)”] Many people assume pipe and tube are the same, but in the wold of process piping engineering, they are not the same. [/wpex]
    • [wpex more=”What is pipe?” less=”What is pipe?(click to hide)”] Pipe is measure in Nominal Pipe Size (NPS) and is offered in different “schedules” which idicate wall thickness of the pipe, where the higher the schedule number the thicker the wall of the pipe. All pipe schedules of a given size have the same OD dimension, but the OD of a particular NPS is not the same as the NPS. As the schedule number gets bigger the pipe ID gets smaller due to the thicker wall. The NPS never matches the actual pipe dimensions, which can be confusing. Standards for pipe schedule and NPS are ASME B36.19M for example, and also in the ASME B31.3 process piping code.[/wpex]
    • [wpex more=”What is tubing?” less=”What is tubing?(click to hide)”] Almost all sanitary tubing and fittings are measured in tube size which is a measure of the outside diameter of the tube. One inch tubing is one inch OD… etc. However, tubing is offered many wall thickness which are normally called out as the actual thickness of the wall or as a “gauge number”. The gauge number represents the various wall thickness available in tubing. The higher the gauge number the thinner the wall. Tube standards are called out in ASTM specifications, such as ASTM A450, and also in the ASME B31.3 process piping code.[/wpex]
    • [wpex more=”Can I weld or attach a pipe to a tube?” less=”Can I weld or attached pipe to a tube?(click to hide)”] Yes, but an adapter would be required. Many adapters are available for different kinds of butt weld joint sizes. Different end fittings are sometimes used where welding is not practical for cleaning and/or maintenance.[/wpex]