However, the non-use or partial use of a technical specification will remove the automatic presumption of conformity which that specification confers on the product. The burden of proof regarding those parts of the technical specification not followed will thus be reversed and the producer, in collaboration with the approved laboratory, will have to demonstrate equivalence with its provisions (i. e. the technical specification remains the European reference as regards the required characteristics and performance of the product in question). ... Essentially, the task of the approved laboratory in cases of deviation is to establish equivalence with respect to the performance of the product in the ITT that would have been obtained by full application of the reference technical specification.
