The project engineer specified that the new Water For Injection (WFI) distribution loop for a pharmaceutical manufacturer in Ireland ought to be fitted with sanitary fittings, including elbows, tees, reducers, ferrules, and clamps, all made of 316L stainless steel with an electropolished internal finish of 20 µ-inch Ra or better. There were three different bids that came in from three various suppliers. The first was a premium European company that met the WFI specifications and offered a lead time of 20 weeks along with a price that took almost 15 percent of the total mechanical budget for the project. The second supplier does not have the ability to provide the material test reports for every fitting because it is a regional distributor working with different brands.
The third and final supplier, Eagle Fittings, did satisfy all the requirements set by the engineer and quoted a lead time of 8 weeks for a price that was about 60 percent of that of the premium supplier.
This way, the engineer awarded the contract to Eagle Fittings and the WFI loop has been in service for 3 years already. The best sanitary fitting definition differs from one application to another — for dairy processors, best means 3-A certified, 316L stainless steel with a competitive price; for pharmaceutical injectables, it means being ASME BPE compliant with controlled chemistry 316L, an electropolished surface finish of 15 to 20 µ-inch Ra and traceability of every material; for craft breweries, it means having a sanitary fitting that is easily cleaned and drained, produced of 316L stainless steel and delivered in a short period of time.
In conclusion, the top sanitary fitting is the one that satisfies all the needs of the particular function being performed, the materials, surface finish, dimensional tolerances, cleanability, drainability, and guarantees, the documentation and deadlines. A sanitary fitting is characterized by the material, which is to be 316 stainless steel and has to be chosen in such a way that ensures that sulfur content is kept at the acceptable levels for welding and corrosion resistance.
What a Sanitary Fitting Is — and How It Differs from an Industrial Fitting
A sanitary fitting refers to a type of a connector made of stainless steel and is also known as hygienic and high-purity fittings. Such fittings connect tubing sections on a process line carrying a product that humans can consume, inject, or otherwise come into contact with. The main distinguishing feature of a sanitary fitting is not its design — sanitary and industrial piping types both feature elbows, tees, reducers, and ferrules. Instead, it is determined by the internal surface finish, material chemistry, ease of cleaning, and documentation.
A fitting of industrial type is built to withstand pressure and connect tubes, and it does both of this while being easy to clean, drain fully, and made of materials that will not corrode, leach, or hold microorganisms when coming into contact with products, an aggressive CIP (clean-in-place) system, and a repeated thermal cycle of SIP (sterilize-in-place). The difference between sanitary and industrial fittings is visible under a microscope and can be confirmed by passing a material test report.
For example, a conventional elbow of stainless steel made for industrial applications might have a cast interior, with the Ra index of over 63–125 microns, using the 304 type of stainless steel that is an adequate material for tasks such as functioning with compressed air, cooling liquid, or hydraulic oil. However, it cannot be used for food processing. Then again, a sanitary fitting will be produced using only the 316L type of stainless steel and will have an electropolished interior with the Ra index as low as 20–32 microns for food production, or 15–20 when used for pharmaceutical production.For a complete introduction to the design principles and the standards that define a sanitary fitting, our article on what a sanitary fitting is explains the requirements in detail.
The Standards That Define a Quality Sanitary Fitting: 3‑A, BPE, and FDA
The sanitary fitting is characterized by belief of the manufacturers who claim it, but it is, in fact, defined by its conformity to the certain, published, and verifiable standard. The standards in question are three most popular in today’s market of sanitary fittings, namely, 3A Sanitary Standards (North American standard for food and dairy processing devices which is associated with a so-called 3A certified fitting made and tested in accordance with 3A requirements, 3A being a trade mark of the standard whose use is controlled by 3A SSI), ASME BPE (Biotechnological and Pharmaceutical standard which is stricter than 3A in terms of material chemistry and surface finish), and FDA compliance (the material specification of elastomer seals and plastics in the fitting).
Whenever a fitting has been marked with the logo symbolizing compliance with the 3A or BPE standards, it has been confirmed to be compliant with the respective standard by a third-party organization. In case a fitting has only a claim about being “suitable for” or “designed to comply with” such standard made by the manufacturer, than it hasn’t been checked by any third parties. The accompanying documents to a quality sanitary fitting include the test results, surface finish proof, and certification of conformity.
How to Choose the Best Sanitary Fitting for Your Application
Choosing the right sanitary fitting for any given process means understanding how the specifications of the ingredients of the fitting comply with the requirements matching the chemical properties of the physical conditions in which the fitting will work. The decision can be facilitated by using the following criteria.
What kind of products will be in contact with the fitting, and what are the conditions for cleaning in place (CIP) and sterilization in place (SIP)? The fitting should be compatible with the product and the products used in cleaning and sterilizing the fittings. 316L stainless steel should be used as a default material for any hygienic equipment. However, in case of high acidity or high chloridcontent at high temperatures, it might be necessary to choose a more expensive material, e.g. AL-6XN or Hastelloy C-22.
What surface finish is required by your standards? The standard surface finish for 3-A dairy and food applications is equal to a polished and electropolished finish that measures 32 µ-inch Ra (0.8 µm). For ASME BPE pharmaceutical application, the required surface finish is equal to 20 µ-inch Ra (0.5 µm) for the majority of surfaces that will come into contact with the product, while 15 µ-inch Ra (0.38 µm) is required generally for the most sensitive applications. The finish must be certified, and the certification must accompany the fitting.
What kind of connection does your system have? Tri-Clamp connections are standardly used for hygienic applications where frequent assembly and disassembly of equipment is required. Automatic orbital butt-welded connection is recommended for permanent installations where a completely smooth and crevice-free internal side of the equipment is needed. Threaded connections (NPT, BSP, or any tapered connections) cannot be used in product contact, as the deadly threads cannot be cleaned with CIP system. The connection type of the selected fitting and the connection system must be compatible.
What documents does your system require? At least a material test report, a surface finish report, and a conformance certificate should be included. In some cases, a positive material identification (PMI) report and dimensional inspection report may also be required, depending on the needs of pharmaceuticals.
What lead time and the after-sale service does the supplier provide? A perfect fitting may be useless if the supplier cannot deliver it on time, or cannot provide any needed support in installing it. Therefore, make sure to ask the supplier about the lead time, as well as the technical support they provide via different means of communication during the process of installation and operation of the equipment.
Eagle Fittings manufactures sanitary fittings — elbows, tees, reducers, ferrules, clamps, and adapters — in 316L stainless steel, with the electropolished surface finishes, the 3‑A and BPE certifications, and the full documentation package that a regulated hygienic process requires. Our fittings are supplied with the material test reports, the surface finish data, and the certificates of conformance as standard — not as a paid extra — because a fitting that will carry a food product, a beverage, or a life‑saving drug must arrive with the proof of its quality already in the box. For a broader look at the full range of hygienic components, our sanitary ball valve collection and the complete range of fittings, valves, and strainers are built for the repeatable, documented performance that a regulated process demands.
Frequently Asked Questions
What is the difference between a sanitary fitting and an industrial fitting?
In sanitary fittings, the internal structure has perfect crevice-free geometry, is made from 316L grade stainless steel, is electropolished to have an Ra value of 32 micrometers or better, uses Tri-Clamp or butt weld connection in place of threaded connections and has the documentation of the finish and material. On the contrary, industrial fittings are meant to withstand pressure and join pipes but they cannot be cleaned with CIP method, be fully drainable or keep bacteria out of the process and thus cannot be used interchangeably in hygienic processes.
What material is best for sanitary fittings?
316L stainless steel is considered the best material when it comes to the sanitary fittings. The presence of molybdenum within the material makes it impervious to the pitting and crevice corrosion caused by hot chlorinated, acidic, and caustic cleaning solutions in CIP. The alloy must have a limited sulfur content for pharmaceutical applications (≤0.020%) if high quality of the welding and the enough corrosion resistance, which is demanded by ASME BPE, are needed. Although for very aggressive chemical environments, more costly materials like AL-6XN or Hastelloy C-22 can be specified, such instances are rare. For a detailed comparison of the material options, our article on 304 vs 316 stainless steel explains the metallurgical differences.
How do I verify that a sanitary fitting is genuinely 3‑A or BPE compliant?
In order to check whether a sanitary fitting is actually compliant, ask the vendor for the 3-A certificate or the ASME BPE certificate, the material test report which links the metal to its mill heat number, the Ra surface finish measurement and its measurement method, and the ISO 9001 or equivalent quality system certificate of that vendor. If the vendor provides these documents willingly, it shows that he is a certified vendor. If he is hesitant or offers only standard compliance documentation, then you are dealing with a vendor who does not comply.
Why are threaded connections not used in sanitary fittings?
Threaded connections introduce spiral gaps between male and female threads that cannot be effectively cleaned with CIP. This leads to residue, cleaning chemicals, and even bacteria becoming stuck in the thread clearance and protected from the cleaning flow of the CIP solution. Sanitary systems use Tri-Clamp or automatic orbital butt-weld fittings to provide a clean system without crevices that is fully drainable.The 3‑A Sanitary Standards and the ASME BPE standard both prohibit threaded connections in product contact for this reason.
References
- 3‑A Sanitary Standards, Inc. — Hygienic Equipment Design and Material Standards. The defining standards for sanitary fittings, valves, and pumps used in dairy and food processing in North America.
- ASME BPE — Bioprocessing Equipment Standard. The pharmaceutical and biopharmaceutical standard for hygienic equipment design, surface finish, material chemistry, and documentation.
- Alfa Laval — Sanitary Fittings and Process Components. A global manufacturer of hygienic fittings, valves, and pumps, with 3‑A and BPE‑certified product lines.
- Swagelok — High‑Purity and Sanitary Fluid System Components. A manufacturer of high‑purity fittings, valves, and tubing for pharmaceutical and semiconductor applications, with BPE‑compliant product ranges.
What essentially qualifies as the best sanitary fitting? It is one that fulfills the criteria in terms of material properties, finish of the surface, dimensional tolerances, ability to be cleaned, and specifications of certificates and documentation pertaining to your operation - all this at a price that does not include the extra charge for a brand that is not required by your auditor. For dairy production, this can be a fitting that is made out of 3-a-certified electropolished 316L at a price corresponding to this industry’s silos.
