Cast Iron Soil Pipe – Green from the Beginning

Cast Iron Soil Pipe’s History of Sustainability

To understand how cast iron soil pipe is a sustainable product, we need to understand the history of piping systems. As cities began to grow, the ever-expanding need to support drinking, bathing, sanitation and other needs was critical to health and safety. Ancient civilizations built aqueducts, tunnels and manufactured pipe from materials such as wood, clay, lead and bronze. The results were less than ideal as these materials degraded and failed over time. However, the early systems served a need and were used for hundreds of years until the introduction of cast iron as a pipe material.

Cast Iron Piping in 17th Century France

One of the earliest full-scale cast iron piping systems was installed at Versailles, France in 1664. The system is still functioning after more than 300 years of service. A cast iron main was constructed to carry water more than 15 miles from Marly-on-Seine to the palace and surrounding area. This was remarkable given the astronomical production costs at the time. This was primarily due to the fact that high-cost charcoal was used exclusively as the fuel to reduce iron ore.

In 1738, charcoal was replaced by coke in the reduction process. This innovation led to cast iron pipe installations in a number of other distribution systems in France. In 1746 it was introduced in London, England, by the Chelsea Water Company. In 1786, Sir Thomas Simpson, an engineer at the company, invented the bell and spigot joint which has been used extensively ever since. This solution was far superior over the earliest cast iron pipe which used butt joints wrapped with metal bans. A later version included flanges, a lead gasket and bolts.

Cast Iron in the United States

Fast forward to the early 19th Century when cast iron piping was imported to the United States from England and Scotland. Its primary use was for the water-supply and gas-lighting systems of larger cities mostly in the Northeast. Pennsylvania, New Jersey and New York all had foundries that manufactured cast iron pipe. By the 1880s, production had spread to the South and Midwest. Again, population growth and city expansion necessitated municipal improvements. To reduce costs, plant locations needed to be closer to new markets. The largest number of foundries built in the 1880s was in the South and Midwest.

The cast iron soil pipe industry emerged in the 1890s as a distinct category. Cities’ demand for waterworks and sewage system grew at a rapid pace. In 1898, there were a total of 71 foundries of which 37 were dedicated to soil pipe production with an annual melting capacity of approximately 560,000 net tons.

Scrap Metal Diverted from Landfills

The manufacturing process has evolved over the last 100 years. Today, the members of the Cast Iron Soil Pipe Institute take ‘environmentally friendly” to a level beyond ‘recyclable’ by utilizing 96% percent post-consumer recycled materials in the production process. This means hundreds of millions of pounds of post-consumer scrap iron and steel are diverted from landfills. Examples include items such as old radiators, car parts like brake drums and more. Few of the materials used in construction can support this recyclability claim.

Recyclable and Reusable

Cast iron soil pipe and fittings are 100% recyclable and can be re-melted and recycled after its useful life. Cast iron piping systems can be recycled to make new cast iron pipe and fittings. Additionally, engineers renovating old building may choose to reuse much of their existing cast iron DWV systems. This lowers renovation costs and decreases the number of new resources required—yet another net gain for our environment.

But there’s more to cast iron soil pipe’s sustainability. Our members also recycle the foundry sand used in the production processes multiple times. When the inert sand can no longer be used in the casting process it is often reused in other applications such as highway construction and structural fill.