The purpose of this standard is to provide reference tables for the conversion of the electromotive forces of thermocouples into their equivalent temperatures and vice versa. The polynomial equations from which these tables come are included in the appendix to this standard, so tolerances are not given. Any error obtained by direct use of these equations will be less than the lowest unit of order. This standard has been established on the basis of the International Practical Temperature Scale of 1968 (EIPT68). Temperatures are expressed in degrees Celsius (symbol t68). The Tables come from experimental work carried out by the National Research Council (Canada), the National Physical Laboratory (United Kingdom) and the National Bureau of Standards (United States), with none of the values depending on the secondary reference points. of EIPT 68. However, when it is desired to calibrate a thermocouple using any of these secondary reference points, the temperatures assigned to them in the current edition of EIPT 68 will be used.