[en] After DIN 21 415, Part 1, 'Method of Testing the Decontaminability of Surfaces' was withdrawn in November 1977 because difficulties have occurred, a new testing method was developed in the BAM as a basis for an improved draft standard. In the draft, the following method of determining the suitability for decontamination is described: On the surface to be tested a circular patch with a diameter of 4 cm is contaminated by means of forced wetting with a solution of radionuclides (Co-60 and Cs-137) for two hours. Immediately following the contamination phase there is begun a three-stage decontamination for which there are applied in well-defined manner successively the decontamination agents water, acid tenside solution and 1-molar HCl. The decontamination factor (DF) is obtained as the quotient of the count rate for the amount of radionuclides used for contamination and the residual count rate after each step of decontamination respectively. By means of a four-stage table there is obtained from the DF value received after decontamination by HCl an estimation of the decontaminability according to the classification very good, good, mediocre or bad. Intercomparison experiments on 14 materials in which 3 testing stations took part, showed complete agreement of results in 10 cases, varaitions of the estimation by one stage of classification in three cases and a disparity by two stages of classification in only one case. (orig.)