Principle

The specimens of a textile floor covering are exposed, at constant load and slippage and for a prescribed number of double passages, to the action of a four-footed wheel (Tretrad), the feet of which are fitted with interchangeable rubber soles.

Lisson tetrad scheme

A Lisson Tretrad machine comprises a bed plate, a vacuum cleaning system and two Tretrad assemblies.

Testing procedure

Test A: 

  • Determination of mass loss of textile floor coverings, also used to assess fibre bind of synthetic pile carpets

Test B:

  • Determination of stair nosing: appearance change of textile floor coverings

Test C:

  • Determination of fibre bind on synthetic loop pile carpets

Test D:

  • Determination of fibre bind (hairiness) on needled floorcoverings and floor coverings without pile

Test equipment

Lisson Tetrad equipment

Lisson Tretrad test equipment