DuraTech Vent Pipe Stainless Steel 24 Length. This pipe has a two small dents in the outer shell. This DuraTech 6 Class A Chimney Pipe Stainless Steel Length is designed for appliances that are tested and listed for use with a 2100° F HT chimney system, such as wood stoves, fireplaces, furnaces, boilers, ranges, water heaters, or other appliances fueled by wood, oil, coal, or gas. To calculate length, subtract 1.25 from each joint overlap of chimney pipe. Allow a minimum of 2 air space to combustibles when installing DuraTech Chimney.