(1) The axial stresses in masonry constructed of blocks may be increased to not more than one and a half times the values set out for brick masonry in sections 67 and 68 for the conditions described therein.

(2)The stresses in masonry constructed of cellular or hollow blocks shall not exceed those for solid blocks , and the compressive strength of cellular or hollow blocks, and the stresses on them, shall be computed on their gross cross-sectional area.

(3)The stresses in masonry built of units which have dimensions different from those prescribed for bricks or blocks shall not exceed the following values, based on the height of the units as laid in the wall-