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Compliance The final feature of the 1994 Guidelines was that all criteria were to be satisfied. Thus a dam would only be regarded as satisfactory if it met the average Individual Risk criterion, the criterion for Individual Risk to the person most at risk, the Societal Risk criterion and the ALARP test, as applicable. THE REVISED CRITERIA Overview With experience in applying the 1994 Guidelines, and with developments internationally, there is now a better understanding of risk to life criteria. Inevitably the current view is more practical and less theoretical than the understanding of 1994. Whether the present view is more or less acceptable to the community at large, is impossible to say. A main reason for publici sing the new criteria is to gauge their acceptance, at least within the technical and scientific communities. The main changes to the criteria are: . . a different approach to the application ofthe ALARP test . new Societal Risk criteria curves The New ALARP Test The change in the application of the ALARP test has to do with the acceptable risk level for upgTaded dams. The changes are: . for an existing dam with risk levels higher than the Limit, compliance would require that the risk b~ reduced to a value lower than the Limit, the acceptable value being determined by application of the ,. ALARP principle (in the 1994 Guidelines the risk was to be reduced to the Objective value) . for an existing dam with risk levels lower than the Limit, but above the Objective, the ALARP test determines whether further risk reduction is economically and practically feasible. If so, the acceptable risk will be determined by consideration of the ALARP principle (in the 1994 Guidelines the question of whether risk reduction is required by the ALARP test was posed in the context of any risk reduction being such as would reduce risks to the Objective value) . for an existing dam with risk level lower than the Objective value, the risk is prima facie acceptable. There may be a legal dury to further reduce risk if the difficulty and cost of doing so is slight or negligible , . for new dams and major augmentations of storage capacity, it would normally be expected that risks would be lower than the Objective value having regard to long term safety considering the potential for further development downstream. Major augmentations are those where the marginal cost of risk reduction is similar to that for a new dam. The new approach is in accordance with the ALARP principles as set out by HSE (1992) and others. In the 1994 Guidelines, a deliberate modification of the HSE view of ALARP was made because of a belief that upgraded existing dams should have the same safety levels as new dams. This view has attracted criticism on the grounds that the marginal costs of risk reduction are generally appreciably higher for existing dams than for new dams. The Working Group has, after consideration, decided that ANCOLD should fall into line with the view as outlined by HSE (1992).