  We compute fully local boundary layer scales in three-dimensional turbulent
Rayleigh-Benard convection. These scales are directly connected to the highly
intermittent fluctuations of the fluxes of momentum and heat at the isothermal
top and bottom walls and are statistically distributed around the corresponding
mean thickness scales. The local boundary layer scales also reflect the strong
spatial inhomogeneities of both boundary layers due to the large-scale, but
complex and intermittent, circulation that builds up in closed convection
cells. Similar to turbulent boundary layers, we define inner scales based on
local shear stress which can be consistently extended to the classical viscous
scales in bulk turbulence, e.g. the Kolmogorov scale, and outer scales based on
slopes at the wall. We discuss the consequences of our generalization, in
particular the scaling of our inner and outer boundary layer thicknesses and
the resulting shear Reynolds number with respect to Rayleigh number. The mean
outer thickness scale for the temperature field is close to the standard
definition of a thermal boundary layer thickness. In the case of the velocity
field, under certain conditions the outer scale follows a similar scaling as
the Prandtl-Blasius type definition with respect to Rayleigh number, but
differs quantitatively. The friction coefficient c_epsilon scaling is found to
fall right between the laminar and turbulent limits which indicates that the
boundary layer exhibits transitional behavior. Additionally, we conduct an
analysis of the recently suggested dissipation layer thickness scales versus
Rayleigh number and find a transition in the scaling. We also performed one
study of aspect ratio equal to three in the case of Ra=1e+8.
