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