DIN 11850 and EN 10357

DIN 11850 was replaced by the European standard EN 10357 in the beginning of 2014 to unify different country specific standards into a common European standard. It is intended for use across all members of the European Union.

DIN 11850, DIN 11851, DIN 11852 are specific standards for hygienic tubes and fittings. The aseptic standards mainly used in the biotech and pharmaceutical industries are covered by DIN 11864, DIN 11865, and DIN 11866.

Even though efforts have been made to unify the standards there are still minor differences between the DIN 11850 and EN 10357.

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Hygienic DIN standards

EN 10357-A /DIN 11850 - Only for hygienic tubes
DIN 11851 - Only for hygienic unions
DIN 11852 - Only for hygienic bends, tees, reducers and tubular fittings
DIN 11853 - Only for hygienic clamp, flange and threaded connections

Aseptic DIN standards

DIN 11864 - Only for aseptic clamp, flange and threaded connections
DIN 11865 - Only for aseptic tees, reducers and bends
DIN 11866 - Only for aseptic tubes

Did you know that tubes and fittings make up 90% of the fluid’s surface contact throughout the process flow?

Watch the animation and learn how tubes and fittings are the vital backbone of any process line.

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DIN 11850 in general

DIN 11850 is a German standard (DIN stands for "Deutsches Institut für Normung", which means "German Institute for Standardization"). DIN 11850 specifies requirements for hygienic stainless steel tubes used in the food, dairy and beverage industries. It covers surface quality, dimensions and materials, ensuring that the tubes are suitable for processes where hygiene and corrosion resistance are critical.

It is important to recognize that DIN 11850 is exclusively applicable to hygienic stainless-steel tubes. The associated fittings, which are compatible with DIN 11850 for use in hygienic process lines, are covered under DIN 11851 to 11853. For those in need of an aseptic process line specifically for biotech or pharmaceutical industries, the relevant standards to consult are DIN 11864 to 11866 which are also covered in the text below.

EN 10357 in general

EN 10357 is a European standard (EN stands for "European Norm"). EN 10357 is a successor to DIN 11850 and harmonizes standards for stainless steel tubes used in the food, dairy and beverage industries. The standard ensures that these tubes meet strict criteria for a number of factors, which are vital for maintaining hygiene and preventing contamination in sensitive production processes.

The main factors included in EN 10357 are material surface, dimensions and tolerances, surface quality, mechanical properties, testing and inspection (visual inspection, dimensional checks, material properties and performance), hygienic design, certification, and traceability.

EN 10357 Comprehensive coverage

EN 10357 is a European Standard that specifies the technical delivery conditions for welded stainless-steel tubes.

EN 10357 is a broader effort to standardize the quality and performance of stainless-steel tubes across Europe, providing a reliable basis for manufacturers and users alike to specify and use tubes in applications where hygiene is of utmost importance. It is designed to harmonize the requirements for stainless-steel tubes providing a consistent quality standard that manufacturers can rely on to ensure the safety and hygiene of food, dairy and beverage products.

• EN 10357-A: Follows the old DIN 11850 sizes
• EN 10357-C: Follows ASME BPE sizes
• EN 10357-D: Follows ISO 2037 sizes

Key aspects of EN 10357 include: material grades, dimensions and tolerances, surface quality, testing, inspection, certification and marking.

DIN 11850 versus EN 10357

As previously noted, there are only minor differences between the two standards, but EN 10357 defines the tolerance for 254 mm tubes which is not defined in DIN 11850. Both standards define the straightness of the tubes to be 0,0015 x length and shall not exceed 2 mm per meter.

Both standards define the same manufacturing process, requirements, and surface characteristics. Please note that EN 10357 uses the prefix CL1/CL2 combined with the surface designation CC/CD/BC/BD whereas DIN 11850 only uses the surface designation CC/CD/BC/BD.

DIN 11850 defines the max pressure measured at 20°C and at 150°C. This is not defined in EN 10357, but we recommend using the max bar pressure mentioned in DIN 11850.

DIN 11850/EN 10357-A: Material quality

Under DIN 11850 and EN 10357, the material quality of stainless-steel tubes is specified in the standard. It is manufactured from stainless steel according to EN 1.4301/AISI 304, EN 1.4307/AISI 304L or EN 1.4404/AISI 316L and characterized by its purity, durability and resistance to corrosive processes. This quality is vital for maintaining the integrity of products flowing through these tubes.

DIN 11850/EN 10357-A: Dimensions and tolerances for precision engineering

These standards define strict dimensions and tolerances. Specifics like diameter, wall thickness, and length are tightly controlled to ensure uniformity and compatibility with existing systems. Alfa Laval offers a range of DIN tubes in the sizes from DN10 to DN200 (16 mm - 204 mm). Please also see table below for tolerances.

DIN 11850/EN 10357-A: Surface finish

Surface finish is critical in industries where hygiene is paramount. DIN 11850 and EN 10357 demand a smooth, non-porous surface to facilitate easy cleaning. The surface finish specifications play a crucial role in the production process.

Alfa Laval’s product range offers the surfaces in mat and polished, both annealed and not annealed. All surfaces with the standard designation BC, BD, CC or CD and internal surfaces with roughness (Ra mμ) value < 0.8. The external surface comes with a roughness (Ra mμ) value < 1.0 or pickled and a (Ra mμ) value < 1.6 in the welded area. All surfaces are according to both DIN 11850 and EN 10357. Please also see table below.

DIN 11850/EN 10357-A: Inspection and documentation

Tubes manufactured under DIN 11850 and EN 10357 undergo rigorous testing. This includes checks for mechanical properties, chemical composition, and surface condition.

Tubes according to this standard must be tested according to DIN EN 10217-7, test category 1 (TC1), or in conjunction with AD-2000-Merkblatt W2 according to test category 2 (TC2).

The measurement of roughness Ra according to DIN EN ISO 4287 is carried out in accordance with DIN EN ISO 4288 and must be checked at least on every 20th tube length. The roughness measurement is carried out at the end of the tube, 5 mm from the end. The joint area and the inner surface of the tube are to be measured and documented accordingly in the acceptance certificate.

A roughness measurement across the weld seam can be agreed separately if needed.

For externally ground tubes of the CD and BD types, ratio part measurements must be carried out to the same extent at least 100 mm from the tube end on the outer surface.

DIN 11850/EN 10357-A: Traceability and documentation

Traceability is an integral part of these standards. Each tube can be traced back to its manufacturing batch, ensuring quick resolution in the event of any material defects. This traceability is a critical aspect of quality control and risk management in sensitive industries.

Documentation should contain manufacturer or supplier name and location, product information, chemical composition, mechanical properties, heat treatment, inspection results, traceability including heat or batch number, and declaration of conformity.

Alfa Laval offers free MTR/3.1 certifications according to EN 10204 on all product-wetted parts from our online material certificate database FindMyCert. This certificate includes all the above-mentioned information.   

DIN 11850/EN 10357-A: Compatibility with fittings and joining methods

DIN 11850/EN 10357-A ensures that the tubes are compatible with various fittings and joining methods common in the industry. This compatibility is essential for a seamless integration into your existing systems and for maintaining the integrity of the connections.

DIN 11851: Union fittings for tubes

DIN 11851 relates specifically to union fittings used together with stainless steel tubes according to DIN 11850. It covers the dimensions and specifications for these fittings, ensuring they align perfectly with tubes manufactured under DIN 11850/EN 10357-A.

DIN 11852: Bends, tees, reducers and clamps for tubes

DIN 11852 extends the scope to other fittings and custom components. This standard ensures that all parts of a piping system conform to the same high standards, maintaining system integrity throughout and fits perfectly with DIN 11850 tubes.

This standard is replaced by the European Standard EN 10374.

DIN 11853: Clamps, connections and treated connections for DIN 11850 tubes

The DIN 11853 standard covers connections used in the process line to connect DIN 11850 tubes and tubular fittings.

The DIN 11853 series pertains to the standards designed for hygienic connections in the food, dairy, and beverage industries. But it also pertains the standard for aseptic connections for biotech and pharmaceutical industries.

The connections are used for connecting hygienic stainless-steel tubes according to DIN 11850, tubular fittings according to DIN 11852, and the aseptic standards DIN 11865/DIN 11866. These connections are designed for easy assembly and disassembly to facilitate cleaning and inspection.

The following connections are covered by DIN 11853

• DIN 11853-1: Hygienic clamps
• DIN 11853-2: Hygienic flange connections
• DIN 11853-3: Hygienic threaded connections

The characteristics that define the DIN 11853 series include: material compatibility, surface quality, design, ease of cleaning and inspection.

Compliance with the DIN 11853 series ensures that the connections used in critical industries meet the highest standards of hygienic performance, thereby safeguarding the quality of the products and the safety for consumers.  

DIN 11864, DIN 11865 and DIN 11866: Aseptic applications

DIN 11864, DIN 11865 and DIN 11866 covers aseptic applications primarily used in the biotech and pharmaceutical industries. These include aseptic connections (DIN 11864) which specifies clamps,  flanges and threaded connections. DIN 11865 covers aseptic tees, reducers, and bends. DIN 11866 covers tubes and piping system.

These standards ensure that even in highly specialized applications, the quality and hygiene requirements are maintained. Aseptic industries are characterized by extreme sterility handling fluids in the process lines like WFI, API, vaccines, intravenous solutions, purified proteins and peptides.

Across all equipment within fluid handling in Alfa Laval we name these products UltraPure. You can find our UltraPure tubes and fittings in the Product Catalogue.   

Alfa Laval comprehensive range of gasket for DIN equipment

Alfa Laval offers a comprehensive range of gaskets for DIN equipment. It is constantly under development due to new production processes and development of materials. In general Alfa Laval can provide gaskets according to your product line. Our range consists of NBR, EPDM, FPM, PTFE and Silicone suitable for clamps, flanges and threaded connections. Please also see tables below for further information about gaskets offered for our DIN product range and the gaskets we recommend for various production processes.

PED, ADI, 1935/2004 and 2023/2006

PED is an abbreviation for “Pressure Equipment Directive” (Directive 2014/68/EU) and it is a legal document that must be followed in the European Union. All systems that contain more than 0.5 bar is required to be according to PED.

PED is referring to serval standards which normally is referred to as the harmonized standards. If the harmonized standards are followed, then it is within the regulations of PED. This ensures a high level of safety for product placed in the EU market.

ADI is an abbreviation for Animal Derived Ingredients. All equipment from Alfa Laval is ADI free, which means all materials and process additives is synthetic. This is to secure there can be no contamination from our components to the customer’s product.

EC No 1935/2004 is a European regulation that lists some requirement to food contact materials. At Alfa Laval we make sure all our manufacturing sites and suppliers are according to 1935/2004 to ensure a high quality level.

EC No 2023/2006 is a European regulation for good manufacturing practice for materials intended to come into contact with food. This Regulation lays down the rules on good manufacturing practice (GMP) for the groups of materials and articles intended to come into contact with food listed in Annex I to Regulation EC No. 1935/2004

Table 1: External diameter tolerance, wall thickness, wall thickness diameter for DIN 11850 and EN 10357

Table 2: Max pressure according for DIN 11850 tubes in bar

The above numbers are calcullated for welded tubes using alloy 1.4301 according to DIN EN 10088-2 and AD-Merkblatt B1B9, 06.1986/07.1995 "Zylindrishcer Mantel ohne Ausschnitt under Innendruck".

Table 3: Overview of DIN products related to specific DIN standards

* A hygienic standard but Alfa Laval complies with the aseptic standard according to DIN 11864. This Product range can be used in both hygienic and aseptic process lines.

Table 4: Surface specification for Alfa Laval Hygienic range Hygienic tubes according to DIN 11850

Table 5: Product and chemical resistance of flexible rubber materials

Ratings

1=unsuitable

2=Limited suitability

3=Normal suitability

4=High suitability

-=Not suitable for other reasons

International designation of flexible rubber materials according to ISO R 1629. ISO = International standard.

Table 6: Seal ring material for clamp fittings