Although the complete evaluation will begin with an examination of the condition of various materials that went through the fire, such as ceramics, furniture, or metal housings, the information primarily needed is the condition of the structural elements that sustain the building loads. Many methods and varieties of test equipment are available for assessing the damage. Some tests can be made at the job site but others require studies of specimens in the laboratory. Although such studies may at times require sophisticated equipment much or all of the information can often be obtained with quite simple equipment. Cores can be used for evaluating strength and modulus of elasticity. Cores should be taken judiciously and from locations where their effect on strength will be minimal though they provide necessary data. Comparisons of these data should be made with data obtained from cores taken from areas that were not exposed to elevated temperatures. These comparisons provide the most reliable information on changes in concrete caused by the temperatures reached. Cores are also useful for giving incidental information about cracking in the interior of a member, the bond to reinforcing steel, and interior temperatures as revealed by color changes. The impact hammer is useful for estimating compressive strength, but only when a considerable number of measurements are made and compared to undamaged concrete of the same quality from within the same structure. The extent of concrete dehydration can be determined by using petrographic methods or by differential thermal analysis (DTA). Specimens for DTA studies should be carefully selected, preferably after the petrographic studies. The petrographic and DTA studies can be extended to assessment of the condition of the aggregate.