Proportioning of the various load carrying parts of buildings and structures shall be governed by working stresses conforming to good engineering practice as set forth in the publications enumerated in this Section, except in cases where the recommendations in such publications are in conflict with specific requirements of this Chapter.
A. Working stresses in masonry shall conform to the recommendations in the latest report of the Building Code Committee of the United States Department of Commerce, under the title concerning "Recommended Minimum Requirements for Masonry Wall Construction".
B. Working stresses in plain and reinforced concrete shall conform to the recommendations in the latest report of the Building Code Committee of the United States Department of Commerce, under the title "Recommended Building Code Requirements for Working Stresses in Building Materials" or to the latest edition of the "Building Regulations for Reinforced Concrete", recommended by the American Concrete Institute.
C. Working stresses in cast iron, in structural steel and in timber shall conform to the recommendations in the latest report of the Building Code Committee of the United States Department of Commerce under the title concerning "Recommended Building Code Requirements for Working Stresses in Building Materials". (1970 Code §349)