To improve present methods available for risk assessment of subway fires and to offer quantitative indexes for design and management of fire prevention of subways

a comprehensive multi-level extensible assessment method of subway fire risks has been developed with the extension theory as its theoretical core on basis of the analytic hierarchy process method and of the expert investigation method.The flow chart of the comprehensive multi-level extensible assessment method is drawn in this paper.The fire risk of a subway was assessed with the developed method to find out the weak parts in subway fires and the key aspects in subway management.The comparative analysis shows that the results are consistent between the method in this paper and the fuzzy assessment method.Therefore

it is reasonable and feasible to apply the extension theory in the assessment subway fire risks

which has properly solved practical problems in risk assessment of subway fires.The method proposed in this paper can also be applied in other relevant fields of risk assessment.Finally

some suggestions on the safety of subway fires are proposed in this paper.