Materials Accepted for Use in Vacuum. Only materials accepted for the relevant Vacuum Classification shall be used on ITER vacuum systems. All material for use in vacuum shall be clearly specified at the design stage and certified in accordance with EN 10204 3.1 or 3.2 before being used in manufacturing. Materials which may be used without prior agreement on vacuum systems with the Vacuum Classifications stated in the table are listed in Appendix 3. Materials listed in this Appendix which are shown as being subject to restricted use for a particular Vacuum Classification are subject to either an overall quota or to particular restrictions on their position of use. Acceptance for any particular vacuum application of such a material shall be obtained by submitting the Material Acceptance Request Form (ITER_D_2MGWR4) to the ITER Vacuum RO. An example of this completed form is to be found in Appendix 3. Materials which are not on the accepted list may be proposed for use in vacuum. If the vacuum properties of the material are not sufficiently well documented for an assessment to be carried out, a programme of measurement of the relevant properties shall be agreed between the proposer and the designated ITER Vacuum RO. Details of materials to be considered for acceptance shall be submitted to the ITER Vacuum RO using the Material Acceptance Request Form (ITER_D_2MGWR4). The
