1.1This Part 3 of prEN 13677, is a specification for thermoplastic compression mouldable sheet consisting of textile glass mat reinforced polypropylene or equivalent products, as described in Part 1 of this specification.The specification defines those parameters which shall be specified plus other parameters which may be specified if required for a particular application or processing method.1.2The specification does not define absolute or nominal values for any parameter. The value of a specified parameter is to be defined by the manufacturer, but this specification defines the method of test to be used to determine the value of each specified parameter and the tolerance about which the parameter shall be controlled by the manufacturer.1.3The parameters to be defined in any GMT specification are defined in 4.1. Parameters to be specified are those, which should typically appear on data sheets. Only a selection of these parameters should be included on the certificate of conformity. The other parameters which are included in a specification should either be nominated by the manufacturer, or agreed between manufacturer and customer. These parameters are defined in 4.2.1.4A selection of the specified parameters should be used for quality control purposes to check the conformity. The specification defines which parameters should be used for checking the conformity of the material. These parameters are defined as part of 4.1. Other specified parameters may be included if critical for a particular application or processing method. This is to be agreed between manufacturer and customer of a production lot and will be reported in the certificate of conformity, which should be in accordance with EN 10204.