From: Air Conditioning, Heating & Refrigeration News | Date: 11/12/2001 | Author: Bernard Nagengast
The necessity for pipe insulation was recognized after the Civil War.
Such insulation was referred to as "clothing" and usually was made of
plaster, felt or even lamp-black, a fine carbon powder. These "modern"
insulating materials had replaced "hair felt," a covering made from cattle hair.
"It was found to have one serious defect - under the action of heat, vermin bred
rapidly in this material."
