def B23T_p(p):
    """function B23T_p = B23T_p(p)

    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 6, Page 6
    """
    return 572.54459862746 + ((p - 13.91883977887) / 0.0010192970039326) ** 0.5
