For centuries, mankind has strived to find the most efficient way to transport water to structures while removing waste. Thanks to the ingenuity of many, carrying water from a well in a bucket became a thing of the past. Many of these older models are antiquated now and are no longer in service. However, it is interesting to see the history of plumbing and where the future may lead.
Before we understood how different materials could harm the human body, water lines were created using lead and asbestos. While they may have posed health hazards, these pipes had their uses. However, while they were innovative for their time, they each have their shortcomings.
Use of cast iron pipes began in France in the mid-17th century. Despite its extensive use throughout the country and into Europe, the United States did not adopt this water transportation method until the 1800s. New Jersey and Pennsylvania were the first two states to use cast iron for water distribution.
They later expanded the use of cast iron pipes to wastewater disposal. Other states adopted this material for use in the municipality distribution. However, by the 1970s, different material types were in use, and cast iron fazed out.
Cast iron pipes have thick walls, making them ideal for home use if correctly installed. The wall thickness helped to preserve the integrity of the pipeline against the surrounding soil and home foundation settling. Cast iron plumbing has a life expectancy of 75 to 100-years, which made it ideal for city use.
Disadvantages of Cast Iron Pipes
While it has a long life expectancy and thick walls to withstand the pressures of underground life, cast iron does have some serious flaws. This material is prone to corrosion and the formation of tuberculation. Over time, the rust flakes off, turning the water brown and leaving particles in the liquid.
Additionally, not all cast iron is made equally. Those pipes made with inferior material breakdown sooner than anticipated.
Cast iron pipes are prone to tuberculation. When bacteria in the line begins to oxidize the iron of the pipeline, tubercules form. These deposits can constrict the flow of water through the line.
In addition to the formation of tubercules, cast iron pipes are prone to channeling. Channeling occurs when the water flow through the pipeline eventually erodes the bottom of the line causing a break.
In the early 1930's, pipe developers created a new form of cement pipe. The new tubes were more durable than traditional cement due to reinforcement with asbestos fibers. Asbestos cement lines were thought to have a long lifespan and remained in use until the 1980s until research indicated the hazards of asbestos. (See "Asbestos Cement Pipe: Why It's a Problem and How Trenchless Can Fix It.")
Health Hazards of Asbestos Cement Pipe
While there is no argument that asbestos fibers are hazardous to humans, the long lifespan, and durability of the pipes are why they are still found in some residences today. The lines are resistant to corrosion, and as long as the line remains unbroken, the asbestos inside is considered inert and safe. It can last up to 100-years.
However, once the lines begin to deteriorate, the asbestos fibers become free. In addition to the threads clogging water lines, exposure to asbestos is dangerous. This fiber can cause mesothelioma and peritoneal mesothelioma in those who have had significant exposure. Due to this serious health hazard, only trained removal experts should test and remove asbestos lines from your home. (Read on in "How to Tell if Your Home Has Asbestos Cement Pipes.")
Vitrified clay pipes are a blend of clay and shale subjected to high temperatures. This exposure to extreme heat causes vitrification of the material, creating an inert ceramic. Use of vitrified clay dates back to around 4,000 B.C.E. It was not until the 1800's that its use became more mainstream Often, this material is found in gravity sewers. Vitrified clay piping was even used in the ancient city of Petra in Jordan as a means of protection via flooding if the center was ever attacked. This system was also of a gravity design. (Read "The History of Vitrified Clay Pipe in Trenchless Installation.")
Thanks to the vitrification process, these pipes can withstand up to 2,000 pounds of pressure, making them ideal for an urban setting. Vitrified clay lines are also resistant to a vast array of acids and are environmentally friendly. The lifespan of vitrified clay pipe can be a few centuries under the right conditions.
The Downfall of Vitrified Clay Pipe
Despite their positive attributes, vitrified clay does have its problems. Even though the lines can withstand up to 2,000 pounds of pressure, if it is left unsupported it cracks quickly over time. In addition to lack of support, extreme stress, like that found from invading tree roots can also cause the plumbing to break. While it is resistant to many types of acid, vitrified clay is susceptible to hydrofluoric acid which will damage it.
Lead pipe usage was prominent throughout history. The Roman Empire began using them to transport water as far back as 2700 B.C.E. By the late 1800s, they were a standard fixture across the globe. However, by the 1960s research was available, warning of the hazards of lead consumption. Many cities and construction firms stopped using lead at that time.
Due to its pliable nature, the lead was popular for water delivery systems. This material was easily formed into various shapes allowing for bends without having to join together several pipes. Despite its soft nature, lead is strong enough to resist pinhole leaks. Its lifespan was set at arounf 100-years.
Health Risks of Lead Pipes
Unfortunately, lead poses a serious health risk, especially for children, the elderly and pregnant women. It is also considered a high risk for healthy adults. Lead pipes and fittings can leak excess lead into the water supply, poisoning those who may drink it. Lead poisoning can cause infertility, intellectual disability, abdominal pain, headaches and death.
Between the late 19th and early 20th century, a new way to coat steel pipes developed. Instead of leaving the steel pipe as it was, workers submerged the line in a bath of molten zinc. This method is known as galvanization.
Galvanized steel began to replace cast iron and lead as the go-to choice for city plumbing needs.
There are many good reasons for cities to choose galvanized steel. The zinc coating protects the pipe from corrosion. While an exposed area on the line may still be vulnerable, a small scratch does not negate the coating's protective quality. The pipe's design offers a long lifespan of around 50-years. However, some areas with rough weather or damage may only see a 25-year lifespan.
Corrosion and Galvanized Steel Pipes
While galvanized steel is an acceptable alternative to lead and cast iron plumbing, there is still some issue that makes it an outdated choice. It is resistant to corrosion; it is not immune to rust. In fact, galvanized steel often rusts from the inside out. Once rust sets in, it can flake off into the water supply.
In addition to rust, not all steel is made with the proper materials. Steel mixed with yellow brass causes dezincification of the coating, negating its benefits. Some steel contains lead, which can lead to lead poisoning if the surface layer is damaged. Underground galvanized steel pipes require a proper covering for structural purposes. This covering can make it difficult to see defects in the line.
With new information, researchers understand how some of the older materials could be considered a hazard to the health of consumers. Therefore, new, safer construction is necessary to take the place of previously used pipes.
Polyvinyl chloride development began in the 1830s. However, polymerization of the polyvinyl chloride, or PVC, did not occur until the late 1860s to early 1870s. By the early 1930s, manufacturers produced tubes of PVC. Testing deemed it safe for water distribution and areas in central Germany began installing the new lines. PVC, however, did not become widely used across Europe and into the United States until the 1950s and 60s.
PVC is an extraordinary substance as it is resistant to abrasion, weathering, most chemicals and corrosion. It is lightweight making it easy to install. Its non-toxic makeup makes it perfect for transporting drinking water. The lifespan of PVC piping is 50-70-years.
While it is an optimal choice for new and replacement pipe, PVC does have some disadvantages. Its lightweight design also means it is easy to crack. PVC does handle high temperatures well, however, when exposed to flame, it does melt at just a few hundred degrees.
PVC comes in a limited size range of ½ to 2 inches. This limitation keeps the material from use for high volume projects. It also needs 24-hours to cure before pressurizing the line. Its simple installation means that often untrained personnel perform the installation and fail to wait for the 24-hours before pressurizing the pipe.
High-Density Polyethylene (HDPE)
High-density polyethylene, or HDPE, production began in the 1930s in the United Kingdom. Despite its resistance to corrosion and abrasion, the material did not gain popularity until the 1950s. In 1955, the first pipes made from HDPE were used in the UK. Use in the United States followed soon after.
Use of HDPE in pipelines has many advantages. HDPE is corrosion and abrasion resistant with a lifespan of 50 to 100 years. Additionally, depending on the design type, this material is quite flexible. It is also adaptable to different types of fittings including HDPE, stab or mechanical. Heat fusion of joints offers a leak-free advantage over other connectors. HDPE is recyclable.
The Cons of HDPE Piping
While it is a good option for pipeline replacement, HDPE does have some disadvantages. Because of the heat fusion requirement, it is difficult to bond the lines. It is flammable and has poor weathering resistance. Under stress, the pipe can crack.
In 1971, Eric Wood needed to repair a pipeline under his garage floor. Not wanting to dig up the existing line, he developed a way to fix the pipe by running a resin permeated fiberglass cloth through it. Once the resin cured, a new line formed through the pipeline and the cured-in-Place Pipe (CIPP) method began. It was not until the 1980s that this method became popular throughout the world.
CIPP is an entirely trenchless method of pipe repair. The existing pipeline is not dug up or removed. While an entire line, complete with multiple bends, restoration is possible using CIPP, rehabilitation of smaller sections is possible. CIPP eliminates root intrusion and increases flow efficiency.
Weather Affects CIPP Curing Time
While CIPP has many advantages of traditional pipe rehabilitation techniques, it is not without its faults. The weather can affect the curing time of the resin. Projects completed on colder, wetter days will take longer to cure than warmer dryer conditions. Additionally, CIPP is not suitable for pipes with large cracks as they will not offer the support necessary for the liner to cure correctly.
Concrete has low tensile strength and ductility, making it a poor choice on its own for pipeline construction. However, combining cement with something of higher tensile resistance, such as rebar, makes the material suitable for sewage drains. Reinforced concrete dates back to the Roman empire with a resurgence of usage beginning in 19th century France. The United States adopted its usage in 1910.
The most prominent advantage of reinforced concrete is diversity. Creators can make reinforced concrete any strength desired based on thickness, design mix and reinforcement. Casting in place is possible as long as the special framework is available. It is economical, making it an ideal choice for cities to use as sewage drains.
However, while it does withstand great tensile and compressive stress, reinforced concrete can corrode at the crown. This corrosion is caused by bacteria as it decomposes organic matter found in the sewer.
The creation of pipelines to transport water and waste is an innovation to celebrate. However, with the understanding of toxins, it is understandable why many municipalities no longer utilize older materials. Instead, newer safer plastics are best.