Since the first of January 1996, every electronic equipment from small electronic apparatus to complete installation has to meet the 89/336 EC directive requirements on electromagnetic compatibility. In particular, shielding is one means of protection but often used at an expensive cost. If EMC solution providers master an optimisation of the whole protection solution of a box including materials, paintings in conjunction with apertures, gaskets and input/output connectors, they can propose best and cost effective solutions. The objective of this proposal is to make an accurate evaluation of-the EM protection given by a box, including materials, paintings, gaskets, apertures aspects by means of appropriate measurement campaigns and use of advanced numerical 3D electromagnetic solvers. From the result of this cooperative research, each partner - specialist in one sphere of competence (gasket provider or conductive painting expert) - will be able to determine the adequation of the elements of its existing products with the degree of protection needed and to elaborate new products with the adequate performance.