The use of expert opinion is considered to be an effective way of assessing complex fire problems where statistical records are not available. The Delphi technique is chosen as the most appropriate means for handling experts' views. Elements chosen by the Delphi group and pertaining to the dwelling fire safety system are arranged in a hierarchical interaction framework. Some of the issues associated with the application of the Delphi technique are discussed and an established hierarchical structure is examined and modified for use in this study. The notions of hierarchy, interactive importance, hierarchical impacts and sequential perturbations are formalised. Finally, the total fire safety evaluation scheme is identified and its utility explained.