What does DIN 6647-1 describe?

DIN 6647-1 describes cylindrical containers for beverages and raw materials with a permissible operating pressure of up to 0.3 MPa and a maximum nominal volume of up to 50 litres.

The containers consist of two deep-drawn shells joined by a weld seam and are primarily used for beer. The standard specifies requirements for materials, volume stability, dimensional stability, burst resistance and test methods. It also defines the hygiene requirements and labelling specifications for these containers.

DIN 6647-1 in detail

There are several requirements specified by DIN 6647-1. Here is a comprehensive overview of all areas relevant to KEGs and other stainless steel containers:

Scope of application

This standard covers containers used as reusable packaging and specifies quality requirements with regard to material, volume stability, dimensional stability and burst resistance.

Normative references

References are made to other relevant standards such as DIN 3542 (barrel sleeves and barrel connection parts), DIN EN 10088-2 (stainless steels) and DIN EN ISO 5171 (gas welding equipment).

Dimensions and designation

The dimensions of the containers are specified in a preferred series, whereby deviations are permitted but must be indicated separately. The dimensions include volume without fittings, diameter and various height specifications. For example, a beverage container with a permissible working pressure of up to 0.3 MPa and a nominal size of 20 is designated as ‘Beverage container DIN 6647-1-0.3-20’.

Material

The components intended to come into contact with the product must be made of stainless, food-grade steel in accordance with DIN 6647-1, for example material no. 1.4301. These must be cold-rolled sheets with smooth surfaces.

Design and hygiene

The containers must be designed so that they are easy to clean and any contamination can be easily removed. Weld seams, radii and transitions must be designed so that liquids can drain completely. After final treatment, the inner surface must have a maximum roughness (Ra) of 1.6 μm.

Requirements

The standard specifies specific requirements for the volume stability, dimensional stability and burst resistance of the containers. For example, no permanent change in volume may occur during the test according to 8.3.1, and during the test according to 8.3.2, the permanent increase in volume must not exceed 0.25% of the nominal volume.

Testing

The test methods described are detailed in Section 8. These include volume stability, dimensional stability and pressure testing. Water is used as the filling medium for the tests, and the test conditions are clearly specified.

Labelling

Containers that are type-tested in accordance with DIN 6647-1 must be permanently labelled with information on the manufacturer, year of manufacture, serial number, permissible working pressure, material and a unique identification mark for the traceability of the materials.

Application example: KEG of a brewery

A brewery uses a KEG (KEG barrel) in accordance with DIN 6647-1 for storing and transporting beer. The KEG in this example has a nominal volume of 30 litres and is made of stainless, food-grade stainless steel (e.g. material no. 1.4301).

It is operated at a permissible operating pressure of up to 0.3 MPa. Before use, the KEG is type-tested to ensure that it meets the requirements for volume stability, dimensional stability and burst resistance.

Permanent marking allows the manufacturer, year of manufacture and material to be traced, which guarantees the quality and safety of the KEG.