This article covers the similarities and the differences between the two fittings and hopefully clears a simple misconception.

The division of sanitary fittings – ASME BPE Fittings and 3A Sanitary Standard Fittings – is something that still comes up a lot when talking to customers. People who are not intimately familiar with the industry can struggle to distinguish between regular sanitary or 3A fittings and BPE fittings.

To begin with, how are the two similar? Well, both BPE and 3A fittings are considered sanitary. Both are measured in the same way sanitary tubing is – by tube OD. This means one can weld the two fitting types together. The tri clamp dimensions for the for the two are also exactly the same – which means when looking for 3A or BPE fittings, one is just as likely to confuse 1” or 1.5” fittings. Some of the fittings also have the same overall dimensions. Both the 14WMP and BPE S14WMP short welding ferrules, for instance, have the same OAL.

That is about where the similarities end, and the rest of this article will highlight some of the differences between the two. 3A fittings have their roots in the dairy industry. They are marked with the 3A symbol, which lets customers know that these fittings are designed specifically for use in the dairy applications. As the industry evolved, 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. BPE fittings are designed specifically to be fully drainable when properly installed.

Another difference that should be highlighted is material availability. 3A fittings are commonly offered in both SS 304 and SS316. BPE fittings are offered exclusively in SS316L. The next thing that really sticks out is the end styles. Have you ever seen I line BPE fittings? The answer is no. BPE fittings are available in exclusively butt weld and hygienic tri clamp ends. One does not see the I line, John Perry, or Q line fittings available in other sanitary fitting styles.

Now, consider surface finish. Both 3A and BPE fittings have what is considered “sanitary” surface finish. Sanitary surface finish is generally considered any finish that is 32 Ra or better. 3A fittings meet this spec and often exceed it. BPE fittings, however, come in several additional flavours. 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. Some BPE fitting lines, such as Sieco Hygienic, even feature a light OD polish on their PC and PD fittings (which are generally insulated). 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. These are the fittings one can see on an uninsulated pharmaceutical process skid. After the PL and PC finishes, we get into the electro polish finishes – PL and PM. These finishes feature a 15 Ra ID w/ EP and either polished or unpolished ODs. These additional finish options are the biggest reason why BPE fittings are generally more expensive than 3A fittings.

Another difference one can see between 3A and BPE fittings is the availability of lot and material traceable certs. On 304 3A fittings, one does not even get heat certs and on 316 they still aren’t always available. BPE fittings, on the other hand, almost never ship without them. Sieco Hygienic fittings even ship with a QR code on the package that allows a smartphone to almost instantly retrieve the MTR. Material traceability and verification are absolutely critical in the pharmaceutical process world.

So there it is – just a few of the similarities between BPE and 3A fittings. If anyone likes to know more about the differences, Sieco also keeps the largest inventory of sanitary fittings, tubing, pumps, and valves. Decades of combined experience will help users to make sure they get the right fitting the first time.

Sieco Vacuum and Hygienic Products Pvt Ltd, Bangalore. Tel: 080-41658078. Fax: 91-80-41658997. Mobile: 092431-10681. Email: mohanam.siecohygienic@gmail.com, siecoengineers@yahoo.com