def B23p_T(T):
    """function B23p_T = B23p_T(T)

    Section 4.1 Boundary between region 2 and 3.

    Release on the IAPWS Industrial formulation 1997 for the Thermodynamic Properties of Water and Steam 1997 Section 4 Auxiliary Equation for the Boundary between Regions 2 and 3

    Eq 5, Page 5
    """
    return 348.05185628969 - 1.1671859879975 * T + 1.0192970039326E-03 * (T ** 2)