The K value is also dependent on the pipe diameter. The L/D value for a 45-degree bend is 16 for a short radius, and 9.9 for a long radius bend. For mitre bends (i.e. no radius) the following are the L/D:

angle   L/D
15      4
30      8
45      15
60      25
75      40
90      60

Hi mtroche,
hope this helps, it's in SI units:
TM
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Loss factor for pipe fittings and bends:

dp = 0.5 * k * roh * v^2

dp       [MPa]    differential pressure
k        [   ]    coefficient factor
roh      [kg/m^3] density
v        [m/s]    velocity

where the loss coefficient is depending on the ratio between radius and diameter:
R        [m]      radius
D        [m]      diameter

R/D        k (90deg)
-----------------------
        smooth    rough
1    ▐   0.21      0.51
2    ▐   0.14      0.30
4    ▐   0.11      0.23
6    ▐   0.09      0.18
10   ▐   0.11      0.20

for any angle other than 90 deg:

k (phi) = x * k (90 deg)

phi      x
------------
30   ▐  0.4
60   ▐  0.7
120  ▐  1.25
150  ▐  1.5
180  ▐  1.7

[these numbers are from the "Dubbel", Springer-Verlag (17 edition, page B50)]