This part of ISO 7628 specifies the minimum requirements for tubing used in air braking systems, to allow its marking in accordance with ISO 7628-1. The conformity of production is the responsibility of the tubing manufacturer.

The marking of the tubing does not automatically imply that the tube assembly (i.e. tube with end-fittings) is appropriate to its use on a vehicle.

It is the responsibility of the tube assembler and/or the vehicle manufacturer to ensure that tests of annex D, relating to the tube assembly itself, are successfully performed.

The tubing defined in this part of ISO 7628 belongs to two possible categories:

• tubing for use up to a maximum working pressure of 1000 kPa¹⁾;
• tubing for use up to a maximum working pressure of 1 250 kPa¹⁾;

and within a temperature range of − 40 °C²⁾ to + 100 °C.

The requirements for coiled tube assemblies are specified in ISO 7375.

¹⁾ 1 kPa = 10⁻² bar

²⁾ Reduction of the lower temperature limit will be considered during a future revision of this part of ISO 7628.