Code of Massachusetts Regulations
780 CMR - STATE BOARD OF BUILDING REGULATIONS AND STANDARDS
Chapter 19 - Concrete
Section 1915 - CONCRETE-FILLED PIPE COLUMNS
Subsection 1915.5 - Fire-resistance-rating protection

Pipe columns shall be of such size or so protected as to develop the required fire-resistance ratings specified in Table 601. Where an outer steel shell is used to enclose the fire protective covering, the shell shall not be included in the calculations for strength of the column section. The minimum diameter of pipe columns shall be 4 inches (102 mm) except that in structures of Type V construction not exceeding three stories above grade plane or 40 feet (12 192 mm) in building height, pipe columns used in basements and as secondary steel members shall have a minimum diameter of 3 inches (76 mm).