A structure shall resist fire for a certain period and shall at the same time exhibit the important individual characteristics which are required of it, for example - its load-carrying capacity - its thermal insulation capacity - its permeability in gas. This standard deals primarily with the load-bearing capacity. The minimum thicknesses necessary in order to provide the required thermal insulation capacity are also indicated for concrete walls and coatings. The load-bearing capacity may, alternatively, be determined by testing in accordance with NS 3904 "Testing of fire-resistance of building structures."