Heat-bonded non-woven geotextiles (such as Typar®) are a variation of the non-woven geotextile type. Typar® geotextiles use continuous polypropylene fibres that are heated together to form a continuous mat. Typar® geotextiles have very good water flow performance and excellent retention of soil fines. Typar® has been used for drainage applications such as trench drains, as a wrapping for perforated pipe, and combined with three dimensional structures to create prefabricated drainage products. Typar® is used when very fine soil particles need to be retained. Heat-bonded non-woven geotextile primary functions: filtration; separation; protection. Secondary functions: reinforcement.