Purpose. This standard prescribes a method for testing thermal battery heat source powder samples for calorific values.calibrating the calorimeter. Since thermal batteries must operate over a wide operating temperature range, the heating value expressed as calories per gram of the material must be closely controlled. The methods contained herein specify sui table conditions obtainable in the laboratory which give results equivalent to actual use. They also assure the required reliability of the equipment, and provide for reproducibility of test results National Bureau of Standards(NBS) certified standard reference material wi 11 be used for this purpose.It includes the method for The following standard samples are available