Classification of Thermoplastic Materials

The term thermoplastic material includes all synthetic polymeric materials which have a softening point lower than 200ºC when tested to BS EN ISO 306: Method A120 Plastics. For the purposes of this Section (and Section 4) thermoplastic materials are classified as TP(a) rigid and TP(a) flexible and TP(b) as follows – (a) To be classified as TP(a) rigid, a thermoplastic material should be – (i) rigid solid PVC sheet; (ii) solid polycarbonate sheet not less than 3 mm thick; (iii) double or multiple skin rigid sheet of unplasticised PVC or polycarbonate which achieves a classification of Class 1; or (iv) a rigid product, a specimen of which (at the thickness of the product as put on the market) when tested to BS 2782-0: Method 508A, extinguishes before the flame reaches the first mark and after removal of the burner, the flaming or afterglow does not exceed 5 seconds. (b) To be classified as TP(a) flexible, a thermoplastic material should be a flexible product not greater than 1 mm thick which complies with the Type C requirements of BS 5867: Part 2 when tested to BS 5438 Test 2 (excluding the cleansing procedure) with the flame applied to the surface of the specimens for 5, 15, 20 and 30 seconds respectively. (c) To be classified as TP(b) a thermoplastic material should be – (i) rigid solid polycarbonate sheet less than 3 mm thick; (ii) double or multiple skin polycarbonate sheet which does not achieve a classification of Class 1; or (iii) a product which, when a specimen of material between 1.5 mm and 3 mm thick, tested to BS 2782-0: Method 508A, has a rate of burning not greater than 50 mm per minute.