ASTM E230-98

1.1 This specification contains reference tables (Tables 8-23) that give temperature-electromotive force (emf) relationships for Types B, E, J, K, N, R, S, and T thermocouples. These are the thermocouple types most commonly used in industry.

1.2 Also included are lists of standard and special tolerances on initial values of emf versus temperature for thermocouples (Table 1), thermocouple extension wires (Table 2), and compensating extension wires for thermocouples (Table 3).

1.3 Tables 4-5, included herein, give data on insulation color coding for thermocouple and thermocouple extension wires as customarily used in the United States.

1.4 Recommendations regarding upper temperature limits for the thermocouple types referred to in 1.1 are given in Table 6.

1.5 Tables 24-43 give temperature-emf data for single-leg thermoelements referenced to platinum (NIST Pt 67). The tables include values for Types BP, BN, JP, JN, KP (same as EP), KN, NP, NN, TP, and TN (same as EN).

1.6 Tables for Types RP, RN, SP, and SN thermoelements are not included since, nominally, Tables 18-21 represent the thermoelectric properties of Type RP and SP thermoelements referenced to pure platinum.

1.7 Polynomial coefficients that may be used for computation of thermocouple emf as a function of temperature are given in Table 7. Coefficients for the emf of each thermocouple pair as well as for the emf of individual thermoelements versus platinum are included.

1.8 Coefficients for sets of inverse polynomials are given in Table 44. These may be used for computing a close approximation of temperature (^oC) as a function of thermocouple emf. Inverse functions are provided only for thermocouple pairs and are valid only over the emf ranges specified.

1.9 This specification is intended to define the thermoelectric properties of materials that conform to the relationships presented in the tables of this standard and bear the letter designations contained herein. Topics such as ordering information, physical and mechanical properties, workmanship, testing, and marking are not addressed in this specification. The user is referred to specific standards such as Specifications E235, E574, E585, E608, E1159, or E1223, as appropriate, for guidance in these areas.

1.10 The temperature-emf data in this specification are intended for industrial and laboratory use.