Hello,
ASHRAE defines a mass wall as a wall having a heat capacity (HC) of
greater than 7 BTU/ft2 * F but I have been unable to find this property
listed in tables of building materials. I am trying to calculate the
heat capacity of a CMU wall and would like to confirm that my
calculation methodology is correct.
Per ASHRAE 1997 Fundamentals:
* 8" concrete block - two cores filled with concrete (normal
weight) - ~130 lb/ft3
* Thickness .67 ft
* Specific Heat ~ 0.22 BTU/lb * F
Therefore NC =(130 lb/ft3 )*(.67 ft)*(0.22 BTU/lb * F)
NC=19.16
Using this methodology even a 4" brick wall has a HC greater than 7 (7.5
to be exact).
Thanks in advance.
Seth Spangler, LEED(r) AP