What does DIN 6647-2 describe?

DIN 6647-2 specifies the requirements for cylindrical beverage and basic material containers with a permissible operating pressure of up to 0.7 MPa and a maximum nominal volume of up to 50 litres.

As a standard, DIN 6647-2 specifies the dimensions, materials, design details and test methods for ensuring the volume stability, dimensional stability and burst resistance of the containers. The standard also contains safety requirements and hygiene regulations to ensure proper use for non-alcoholic beverages. These containers are mainly used as reusable packaging.

DIN 6647-2 in detail

There are several requirements specified by DIN 6647-2. Here is a comprehensive overview of all areas relevant to KEGs and other stainless steel containers:

Scope

DIN 6647-2 is primarily intended for containers for non-alcoholic beverages and describes requirements regarding material quality, volume stability, dimensional stability and burst resistance in order to ensure high quality and safety.

Normative references

The document refers to other standards that are relevant to specific requirements, such as DIN 3542 for barrel sleeves and barrel connection parts and DIN EN 10088-2 for stainless steels.

Material

The parts of the containers that come into contact with the contents must be made of stainless steel suitable for foodstuffs, such as material No. 1.4301. These steels must be specified in accordance with DIN EN 10088-2 and have smooth surfaces (surface finish 2B).

Hygiene

The containers must be designed so that they are easy to clean and dirt can be easily removed from both the inside and outside. The surface roughness must not exceed 1.6 μm to prevent contamination of the contents.

Requirements and tests

The standard defines precise test methods to ensure volume stability and dimensional stability:

- In terms of volume stability, only minimal volume changes may occur after a pressure test.

- Dimensional stability is checked by drop tests and pressure load tests, whereby diameter deviations and permanent changes in shape are only permitted within narrow tolerances.

- To ensure burst resistance, the containers must withstand a test pressure of at least 6 MPa and must also be equipped with a safety burst point that safely reduces the excess pressure at a maximum of 4.5 MPa.

Marking

Each container must be permanently marked with information such as the manufacturer, year of manufacture, permissible working pressure and material in order to ensure traceability.

DIN 6647-2 thus ensures that cylindrical beverage and raw material containers meet high quality and safety requirements and can be used reliably in practice.

Application example: KEG of a beverage manufacturer

A beverage manufacturer uses stainless steel KEGs in accordance with DIN 6647-2 for filling and transporting non-alcoholic beverages. These stainless steel kegs usually have a nominal volume of 30 litres and can withstand an operating pressure of up to 0.7 MPa.

The keg consists of two deep-drawn shells connected by a weld seam and equipped with a safety burst point to safely release pressure at 4.5 MPa. Thanks to their smooth inner surface and design in accordance with the hygiene requirements of the standard, the kegs are easy to clean and reuse, which ensures the quality and safety of the beverages.