Material Woven and Knitted PVC Fabric Industrial woven and knitted plastic is currently used for purposes where specifications call for a high degree of protection against atmosphere wind and rain The purpose for which it is used is from raincoats to inflatable structures With few exceptions the material consists of a fabric woven or knitted in polyamide or polyester or derivatives there of Both sides of the structural fabric are coated with soft polyvinyl chloride PVC The PVC layer ensures that the material is air and waterproof and protects the fabric against chemical and action fire The fabric gives the plastic stability and strength and determines the stretch ability of the material BaseFabric The basefabric consists of yarn knitted semibasket or full basket woven The warp is the yarn running in the longitudinal direction of the woven fabric and the weft is the yarn running from side to side of the fabric or circumference of tubing The number of threads per centimetre is quoted for the warp and weft The thickness of the yarn is of considerable importance This is normally quoted in denier or dtex Denier is an earlier unit of measurement The Decitex dtex is the weight of 10000 metres of yarn expressed in grams Denier is the weight in grams of 10000 yards of yarn 1000 denier 1 100dtex yarn Basket weave also called panama weave gives the best tear strength The strength of polyamide and polyester yarns is roughly equivalent Polyamide yarn will stretch more and for this reason is better equipped to absorb a sudden load eg tearing The ability of the yarn threads in the woven material to interact to ensure that the load is taken by several threads is an important factor in tear strength Knitted fabrics immediately form knots when torn and prevent any further damage by tearing ROCVENT INC MINE TUNNEL VENTILATION 6 wwwrocventcom