@classmethod
def _waterSupp(cls, T, P):
    """Get properties of pure water using the supplementary release SR7-09,
        Table4 pag 6"""
    tau = (T - 273.15) / 40
    pi = (P - 0.101325) / 100
    J = [0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 3, 3, 3, 
        3, 3, 3, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 6, 6, 6, 6, 7, 7]
    K = [0, 1, 2, 3, 4, 5, 6, 0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 4, 5, 0, 1, 2, 
        3, 4, 5, 0, 1, 2, 3, 4, 0, 1, 2, 3, 4, 0, 1, 2, 3, 0, 1]
    G = [101.342743139674, 100015.695367145, -2544.5765420363, 
        284.517778446287, -33.3146754253611, 4.20263108803084, -
        0.546428511471039, 5.90578347909402, -270.983805184062, 
        776.153611613101, -196.51255088122, 28.9796526294175, -
        2.13290083518327, -12357.785933039, 1455.0364540468, -
        756.558385769359, 273.479662323528, -55.5604063817218, 
        4.34420671917197, 736.741204151612, -672.50778314507, 
        499.360390819152, -239.545330654412, 48.8012518593872, -
        1.66307106208905, -148.185936433658, 397.968445406972, -
        301.815380621876, 152.196371733841, -26.3748377232802, 
        58.0259125842571, -194.618310617595, 120.520654902025, -
        55.2723052340152, 6.48190668077221, -18.9843846514172, 
        63.5113936641785, -22.2897317140459, 8.17060541818112, 
        3.05081646487967, -9.63108119393062]
    g, gt, gp, gtt, gtp, gpp = 0, 0, 0, 0, 0, 0
    for j, k, gi in zip(J, K, G):
        g += gi * tau ** j * pi ** k
        if j >= 1:
            gt += gi * j * tau ** (j - 1) * pi ** k
        if k >= 1:
            gp += k * gi * tau ** j * pi ** (k - 1)
        if j >= 2:
            gtt += j * (j - 1) * gi * tau ** (j - 2) * pi ** k
        if j >= 1 and k >= 1:
            gtp += j * k * gi * tau ** (j - 1) * pi ** (k - 1)
        if k >= 2:
            gpp += k * (k - 1) * gi * tau ** j * pi ** (k - 2)
    prop = {}
    prop['g'] = g * 0.001
    prop['gt'] = gt / 40 * 0.001
    prop['gp'] = gp / 100 * 1e-06
    prop['gtt'] = gtt / 40 ** 2 * 0.001
    prop['gtp'] = gtp / 40 / 100 * 1e-06
    prop['gpp'] = gpp / 100 ** 2 * 1e-06
    prop['gs'] = 0
    prop['gsp'] = 0
    return prop
