(1) For solid masonry building-units of the dimensions of bricks, the stresses in masonry due to axial vertical loads calculated as evenly distributed stresses over-

a) the cross-sectional area of a wall; or

b) if there are openings in a wall, the reduced cross-sectional area between openings; or

c) the cross-sectional area of a column;

shall not exceed the stresses set out in Table XX for the compressibe strength of such units and class of mortar set out in that Table:

Provided that-

i) the slenderness ratio does not exceed 12; and

ii) the compressive strength of such masonry building-units is determined in the manner described in section 5 for the building-units concerned.

TABLE XX
BASIC STRESSES FOR MASONRY WALLS AND COLUMNS

(2) The permissible stresses set out in Table XX shall be designated the basic stresses for masonry.

(3) Basic stresses for intermediate strengths of the building-units aforesaid may be obtained by liner interpolation between the stresses set out in any one column of that Table.