Cast iron pipe is historically known for its use as a pressure pipe for transmission of water, gas and sewage. This type of pipe has also been used for water drainage during the 19th and 20th centuries. It is made up of a cast iron tube and was commonly used uncoated. Later, it was discovered that coatings and linings reduced corrosion and improved hydraulics. During the 1970s and 1980s, most manufacturing plants began transitioning to ductile iron pipe, which is a direct development of cast iron. Today little cast iron pipe is manufactured.
In the 17th century, the very first cast iron water pipes were made. These pipes were made and installed to distribute water throughout the gardens of the Château de Versailles. How old these pipes are makes them considerably historically valuable. Even after undergoing extensive refurbishment in 2008, 80%of the original pipes still remain today.
Cast iron was used as a replacement for the original elm pipelines that were laid in the ground earlier, as cast iron proved to be a far more beneficial material for the manufacturing of water pipes. These water pipelines were made up of individually cast sections of cast iron. These sections were often referred to as “sticks” and were joined together by a bell and spigot joint. A bell is when the end of a pipe stick is flared out. This can also be termed a “socket” and is there to enable the spigot (or smaller) end of the next stick to be inserted and create a joint. Gaps in these joints were sealed with oakum (a preparation of tarred fibre used in shipbuilding for caulking,) to prevent any water from leaking out. A molten lead joint was then run around the socket to ensure that the oakum seal would remain in place.
Throughout the years, there have been three main methods for manufacturing cast iron pipes:
Horizontal Casting - The very first cast iron pipes were produced in horizontal moulds, the core of which was supported by iron rods that would eventually become part of the pipe. Horizontal casting would usually result in an uneven distribution of metal around the pipe circumference. This was due to slag that would collect at the crown of the pipe which would create a much weaker section.
Vertical Casting - The very first occurrence of a pipe being cast vertically in a pit was in 1845. This worked out so well, that by the end of the century all pipe was being manufactured by this method. The aspect that made this a superior means of manufacturing is that all the slag would collect at the top of the casting, and could be removed simply by cutting off the end of the pipe. While this became the best method for casting, there was still an issue of pipes suffering from off center bores. This would result in one side of the pipe being thicker than the opposite side which was caused by the core of the mould being placed off center.
Centrifugal Casting - After it was invented by Dimitri Sensaud deLavaud in 1918, a lot of cast iron pipe manufacturing shifted to the dramatically different technique of centrifugal casting. In this casting method, a rotating mold is continuously spun while molten metal is poured inside of it. This allows the metal to be thrown towards the inside of the mold wall where it solidifies after cooling. Modern pipe production continues to use this method of casting.
While the first occurrence of standardised cast iron pipes was in 1917 Britain, these pipes are still commonly used today. If you have any questions about what your sewer pipes are made of, feel free to give Harts Services a call at 253-345-7222 to request a service, and we will set up a camera scope that will answer any questions you may have. Our Tacoma plumbing company is here to answer your questions and meet your needs.