The Rise and Fall of Orangeburg Pipe

August 22, 2022

Submitted by Greg Johnson, APWA-MN History Committee

The rise of Orangeburg pipe
Orangeburg pipe was commonly used in Minnesota homes for sanitary sewer main, service lines and vent piping from the 1940s to the 1970s. Originally used as conduits in the telegraph, telephone and electrical industries, use of the pipe for sewer and water systems grew dramatically due to the steel demand during World War II. 

Also known as fiber conduit, bituminous fiber pipe or Bermico, Orangeburg pipe was originally produced by the Fiber Conduit Company of Orangeburg, New York, as early as the 1890s. Though there were a number of competitors, Fiber Conduit Company was by far the largest producer. 

The post-World War II housing boom led to the biggest use of this style of pipe, and at this time it became exclusively referred to as Orangeburg pipe regardless of manufacturer. In fact, Fiber Conduit Company changed its name to Orangeburg Manufacturing Company in 1948.

Defining Orangeburg pipe
Orangeburg pipe is made up of layers of compressed ground-up wood fibers that are impregnated with liquefied coal tar pitch. Typical sizes are 2, 4, 6, 8, 10, 12, 15 and 19 inches in diameter. As a visual example, think of a Minnesota paper birch tree with coal tar pitch spread between each densely packed layer of birch bark. The inside of an Orangeburg pipe resembles a cast iron pipe, though cast iron does not develop the same rust deposits.

 

A closer look at a recently dug-up Orangeburg in Mora, Minnesota. The pipe is long past its useful life, showing significant rusting due to moisture penetrating its walls.

Cracks start to show: The fall of Orangeburg pipe
Orangeburg pipe was once thought to be impermeable to tree roots. This might have been true for new pipes but, as the black tar pitch dries moisture from sewer flows penetrates the pipe walls, roots find their way in. Unfortunately, many homeowners did not learn this lesson until their service lines failed.

The useful life of Orangeburg pipe was previously thought and advertised to be 50 years. Any pipes in use for this long were well past their lifespan and likely suffered tree root intrusion. Any house still standing today with Orangeburg pipe was most certainly built immediately after World War II.

The rapid increase in use of polyvinyl chloride (PVC) pipe used in the 1970s for both water and sewer lines quickly brought a definitive end to the use of Orangeburg pipe – so much so that the Orangeburg Manufacturing Company closed for good in 1974.

Greg Anderson, PE (MN), is a senior project manager with SEH and the company’s regional leader over the civil south engineering practice.