The spring guide to aseptic fittings

If you are responsible for a process plant, you are undoubtedly familiar with the challenge. There is a wide range of different fittings available, and the requirements for documentation, hygiene and delivery reliability can be high. Regardless of whether your plant transports media in liquid, powder or gas form, the choice of coupling is important for maintaining good hygiene. And this is where you can save time on maintenance if you make the right choice from the start. 

The common denominator for the solutions we review is AISI 316L stainless steel. It is the industry standard for hygiene-sensitive applications, and the material forms the basis for the operational reliability you expect in your production. 

But how do you navigate DIN standards, Ra values and coupling types? We dive into the technology behind aseptic fittings so that you are equipped to make the right choices. 

Aseptic fittings are not just pipe connections. They are designed with one specific purpose in mind: to minimise the risk of bacterial growth and product residue accumulation. 

The difference is in the details. An aseptic coupling has extremely smooth surfaces and precise tolerances. The construction ensures that the gasket aligns perfectly with the pipe, so that no ‘pockets’ are created where the medium can hide. This means that when you carry out your cleaning and sterilisation processes (CIP/SIP), you can be sure that the liquid reaches every corner of the system. 

For those who produce milk, beer, juice or pharmaceuticals, this is not a luxury but a necessity. A single contamination can mean discarded batches and costly production stoppages. That is why aseptic fittings are the standard when food safety and product quality must not be compromised. 

The most commonly used aseptic fittings you will encounter include union fittings, blind nipples and weld on. In addition, there are flange liners, flange nuts and clamp liners for those places in the plant where you need quick disconnection. 

In the process industry, we typically work with three main types of aseptic couplings. They all fall under the DIN 11864 standard, but serve different purposes in your daily operations: 

• Shape 1 - Aseptic union coupling (DIN 11864-1): This is the classic screw connection. It is robust and suitable for locations that do not need to be disassembled daily, but where hygiene must still be top notch. 
• Shape 2 - Aseptic flange coupling (DIN 11864-2): Flanges are the solution when you need extra strength and tightness, often at higher pressures. They are bolted together and provide an extremely stable connection. 
• Shape 3 - Aseptic clamp coupling (DIN 11864-3): This is the favourite for busy maintenance teams. The clamp solution can be assembled and disassembled without tools. This makes it ideal for places in the plant where you often need to inspect, clean manually, or replace parts. 

Confusion often arises around pipe dimensions. The aseptic DIN standard is available in three different series, and it is critical that you choose the series that matches your existing pipe connection: 

• Series A: Suitable for DIN food pipes. 
• Series B: Suitable for ISO tubes. 
• Series C: Suitable for DS/SMS or INCH dimensions. 

By choosing the correct series, you ensure a smooth transition. 

Would you like to learn more about the different types of couplings? Then watch the video, where we go through them one by one. 

As mentioned, the material quality for aseptic fittings is AISI 316L/EN 1.4404. It resists the aggressive cleaning agents and high temperatures your plant is exposed to on a daily basis. But the quality of the steel is only half the story. Surface roughness is just as important. And why is this an important factor? Because a lower Ra value means a smoother surface. Microorganisms and product residues find it difficult to adhere to a smooth surface. The surface roughness of aseptic fittings is typically either Ra < 0.8 µm or the even finer Ra < 0.4 µm. 

In practice, this means you get: 

• Higher product safety: The risk of biofilm is minimised. 
• Effective cleaning: CIP/SIP processes become more effective and can potentially be carried out faster. 
• Longer service life: Proper surface treatment in combination with the right sealing materials extends the service life of the plant. 

Aseptic fittings are particularly common in food and beverage production, e.g. in dairies, breweries, juice and concentrate lines, and in the production of liquid foods. They support high hygiene requirements, long shelf life and a consistent level of quality across batches. You will also find them in the pharmaceutical and biotech industries, where even minimal contamination can have a major impact on efficiency, patient safety and regulatory approvals. 

The choice of aseptic fittings should be based on process requirements, existing piping systems and cleaning strategies. As a rule of thumb, consider the following: 

• Media type and cleaning: What products and cleaning/disinfecting agents will the system handle, and what temperature and pressure conditions are you working with? 
• Pipe standard: Is the plant built with DIN, ISO or DS/SMS dimensions, and which DIN 11864 series (A/B/C) does it best match? 
• Hygiene level: Are there particularly strict regulatory or customer requirements that call for a lower Ra value and specific material certificates? 
• Service and maintenance: How often are couplings expected to be separated for inspection, and is there a need for easy removal and reinstallation, e.g. with clamp solutions? 

As a supplier to some of Europe's most prominent food and pharmaceutical companies, we know that quality and delivery time are paramount to your business. That is why we stock a wide range of high-quality aseptic fittings, so you avoid unnecessary waiting times for critical components. 

Of course, we deliver with full traceability and batch numbers on our hose solutions. But we also know that standard products do not always solve the problem. Do you have special requirements, or are you facing a challenge that requires a customised solution? In our in-house assembly workshop, we can assemble and customise solutions exactly to your needs. This gives you the peace of mind that the components will fit perfectly into your production from day one. 

Contact us today on +45 7020 0422 or via inquiry@alfotech.eu. We are transparent in helping you with technical advice that will ensure your operations run smoothly.