Abstract: Tubular pipe insulation is made from a glass fiber mat produced utilizing a rotary glass fiberization process. A spinner disc is rotated to centrifuge molten glass through fiberization holes in an annular sidewall of the spinner disc and form primary glass fibers. The primary glass fibers are attenuated and formed into a veil where the fibers are dispersed to reduce in length the fiber networks formed from the fibers. Binder is applied to the fibers and the fibers are collected into a mat that, when pulled apart by longitudinally directed, opposing forces, separates across the width of the mat into two mat sections having feathered edges with substantially no fibrous stringers extending beyond the feathered edges for a distance greater than about four inches. The leading mat section is then wound about a mandrel and the binder in the mat is cured to form the pipe insulation.