# coefficient of heat transmission for wall assembly logic?

i don’t really understand this methodology. for instance in example 16.1 in ballast blue book it gives various R values.
and these R values are provided for specific materials in specific thicknesses, yes?
then there is brick which is provided with a value of 0.11/inch which you multiple by the brick thickness to get the whole R value of the unit (3.625”x0.11R/“=0.4).
then instead of an R value for GWB they give a C of 2.22 which you invert (1/2.22=0.45).
now you are set up to sum R’s so you can invert it to get an overall U (or coefficient of heat transmission) for the wall section (or whatever).
but the text says “The R and C values for the various components are given in the table. however they must be converted to /conductances/ (my emphasis) for the thicknesses used.”
and i don’t see any conductance (k) used. it seems to me i just used the R values and converted a C to R. then - well them it seems like i was given a k value for the brick (?) of 0.11/inch and converted the conductance to a R by multiplying by the thickness per inches.
is the text a typo here basically?
A. am i missing something?
B. how eoin you need to use k exactly? just like i used it? i mean you would never convert an R value to k would you?
thanks

Please sign in to leave a comment.

## Comments

0 comments