The object of this ASME Code is to provide a test procedure for evaluating the performance of waste fuel combustors with energy recovery using the boiler as a calorimeter. These procedures apply when the variability and waste fuel composition results in a lack of confidence in obtaining representative samples for laboratory analysis. This Code is used to determine (a) the thermal efficiency of system combusting waste fuels (b) the thermal capacity (heat input per unit time) of systems combusting waste fuels (c) the higher heating value (HHV) of waste fuels. The rules and instructions given in this Code apply to all waste combustor systems with energy recovery. Test methods of this code apply to solid, liquid, or gaseous waste fuels. Instructions are given to determine the thermal capacity and thermal efficiency of waste combustor systems by applying the concept of using the boiler as a calorimeter. In addition, the HHV of the waste fuel can be determined by weighing the waste fuel that has been consumed during the test.