The cast-iron steam and hot water heating radiators (referred
to herein as "radiators") shall consist of an assembly of small tube cast-iron sections connected by tie rods at the top and bottom, and shall include the tappings, nipples, and fittings. The height of the radiator shall be 19 or 25 inches (462.60 to 635.00 millimeters (mm)) with four tubes per section, or 25
inches (635.00 mm) with six tubes per section, as specified (see 6.1). The number of sections for all radiators shall be an even-numbered amount from 2 to 56, as specified (see 6.1 and 6.4).