The Lifespan and Dangers of Old Piping Materials Vs. Plastics and Liners
Older plumbing materials included cast iron and lead. Since their inception research indicates health hazards associated with the materials. Newer materials are safer than before.
Creating a plumbing infrastructure capable of transporting water to residents and waste away from them is arguably one of the greatest feats man has accomplished.
Through design and innovation, humankind has learned what materials work best to achieve this task. While many of these older products are not the go-to solution anymore, looking at the advantages and what went wrong can help designers in the future.
Older Piping Material
From the ancient Egyptians, humankind has searched for the most efficient way to transport water and remove waste. While the materials used throughout the years were innovative, they didn't always stand the test of time.
Lead pipes were most commonly used for plumbing in the past. The first known use of lead pipes was in the Roman Empire. They used the pipelines to transport water through aqueducts, which delivered water to public wells, fountains, and homes. Due to its non-rusting nature, lead became a standard fixture in homes around the globe.
Lead is malleable, making it ideal for water delivery. Pipes can bend to accommodate any design without having to use joints, which may cause leaks. The lead material itself is resistant to pinhole leaks despite being soft enough to be easily manipulated. Despite its pliable nature, lead has a lifespan of around 100 years. (Read also: How to Tell if Your Home Has Lead Pipes and How to Replace Them.)
The hazard of using lead as a water delivery system comes from the material itself. Lead, when consumed, is a health risk. While anyone can succumb to lead poisoning, pregnant women, children, and the elderly face the most significant threat. Lead poisoning risks include headaches, intellectual disability, infertility, and death.
In the early 1960s, the Center for Disease Control and Prevention established acceptable lead levels in the blood to be as much as 60µg/dL. Since 1991, however, the C.D.C. has reduced the allowable level to 10µg/dL. Studies have indicated that intellectual disability occurs at a faster rate with lead levels above this threshold.
Cast iron (CI) dates to the 17th century, where it was found readily throughout France and into Europe. It later came to the United States in the 1800s. Initially, the iron pipes were uncoated; however, it was found that coating or lining the interior of the cast iron pipes reduced corrosion in the line.
Until the mid-1800s, the iron was cast in horizontal molds supported by small iron rods. These rods became part of the pipe. However, the casting process made the pipe circumference uneven, and there would be slag collection at the crown of the line. As a result, changes were made to casting.
Due to its thick walls and life span of 75 to 100 years, cast iron became the popular choice for municipality distribution and home plumbing. The thickness help withstand the pressures of settling soil.
Cast Iron Dangers
While cast iron was the optimum choice up until the 1970s, it does have its disadvantages. In some areas, parts of the United States along the southern coast, the environment can cause the pipes to fail in as little as 25 years. The early failure is due to the high salt content in the soil and the air's high humidity. The environmental factors cause the pipelines to corrode, usually starting with a pinhole leak along the pipe's bottom, which continues to grow as the pipe ages.
Cast iron is also a heavy material that requires support at regular intervals to keep the pipe from becoming damaged. As the pipe ages, it can become quite brittle and will break easily when hit.
Cast iron is prone to tuberculation, especially in lines that carry raw sewage. Tuberculation is the growth of bacteria along the line that causes corrosion and iron oxide precipitation formation. The iron oxide precipitation can fall into the water making the water have a dirty or red appearance. It also restricts the flow through the line. (Read also: Cast Iron Plumbing: Cleaning and Repairing Tuberculation in Pipes.)
Copper is still a standard pipe used to transport water in homes and businesses. Typically, this piping is found in heating and air conditioning, but it is sometimes still found under sinks and water heaters. Thicker copper lines can be used for underground water transport.
Copper has a more extended history than many other pipeline materials. Copper pipe was first used by the Ancient Egyptians to distribute water starting in 2150 B.C.E. The ancient Romans also adopted copper lines as they began replacing their lead lines. It rose to popularity by the 1940s worldwide and became one of the most used materials for plumbing.
On average, copper has a lifespan of up to 70 years. However, highly acidic water and other external conditions can reduce the life of the copper pipe. Copper is popular due to being lead-free, reliable, and impermeable.
While copper is a durable metal, it is susceptible to corrosion. When water pH is between 5 and 6.5 instead of neutral 7, it is considered acidic. The acidity eats away at the copper pipes' walls and begins to cause pinhole leaks and leaks at joints and seams. The corrosion reduces the copper plumbing life from 70 years to around 20 years.
There is concern over copper toxicity. Small amounts of copper are not hazardous and are even necessary for normal brain function. However, too much can be toxic. Exposure to constant high levels of copper has been linked to Alzheimer's. It is rare to find toxic amounts in drinking water due to the pipes. However, if there is too much pipe compound containing copper at the joints, it could lead to copper toxicity.
Probably the most significant disadvantage most consumers see is the cost. Copper is not cheap, especially in comparison to plastic options. In some areas, installing new copper lines can cost two to three times as much as plastic alternatives. It is high cost makes it a thief magnet in some areas where it can be stripped and sold for high-dollar scrap.
Plastic Plumbing Material
As plumbing developed, pipes have been new trends that outlast most metal options without some of the setbacks. While most plumbers swear by plastic alternatives, there are still a few disadvantages to go along with the benefits. (Read also: The Lifespan of Steel, Clay, Plastic and Composite Pipes.)
Polyvinyl Chloride (PVC)
Polyvinyl chloride (PVC) was developed first in 1835 by the French chemist Henri Victor Regnault, then again in 1872 by German chemist Eugen Baumann. However, neither man held the patent on the design. It wasn't patented until 1912 when another German chemist named Fredrich Heinrich August Klatte used sunlight to polymerize vinyl chloride.
While Klatte did patent his new-found substance, it wasn't widely used until the early 20th century when Waldo Semon developed it for B.F. Goodrich a use to make fabrics water-resistant. Later it was developed into tube form for transportation of water.
Unlike other pipe material, PVC is durable and resists corrosion from chemicals, hard water, bacteria, sewer gas, or disinfectants. PVC is a durable substance that does not require additives to prevent decay. It does not contain lead, BPA, or plasticizers.
PVC pipes have a rating of 100-year lifespan. However, studies of the exhumed line estimate that the line may last as long as 300 years given the right conditions.
Despite being a popular choice for replacement pipes, there are a few disadvantages to using PVC. There is a cure time for new PVC pipes after installation. You should always wait at least 24 hours before pressurizing the line. Only use skilled installers to ensure that the line is properly cured before pressurizing.
While PVC is lightweight, which makes it desirable to contractors, the design can be a flaw. The pipe itself is relatively fragile when considering it is a plastic pipe. If stepped on or dropped, the tube can crack. If installing in an earthquake-prone area, installers should remember that PVC is more susceptible to cracking during an earthquake than other types of plumbing.
PVC is limited in size options. A pipe is only available in sizes from ½" to 2" in diameter. With bulky joints, they are not ideal for tight places. Also, while PVC can handle high-temperature water, the plastic polymer will melt if exposed to a flame.
Cured-in-place pipe (CIPP) is a genuinely trenchless method of repairing water and sewer lines. Instead of digging up the existing line, removing it, and then replacing it with new pipes, workers run a resin permeated fiberglass cloth through the damaged pipe. Once in place, they allow the resin to cure, and it forms a new line within the old one.
While this pipe repair method was developed in the early 70s, it didn't become popular until a decade later in the 1980s. Today, it is one of the more popular options to repair lines. CIPP has a life expectancy of more than 50 years.
The advantage of using CIPP is that it doesn't take as much time and effort to repair the line. With less downtime and no open trench, projects cost less. Additionally, as it is a fiberglass cloth, the new line is malleable when pulled in place. Workers can use it to go through multiple bends without having to connect the lines to one another. With the liner, root intrusion is eliminated.
While CIPP is a good alternative for the traditional pipe repair, there are a few disadvantages to using this process. The pipe must first be clear of all debris before beginning the repair. While CIPP is a lower-cost alternative, having to remove roots and other blockages can increase the cost. If there are large cracks, CIPP is not the choice for the repair.
Another disadvantage is weather plays a role in curing time. Rainy or cold days can make the resin take longer to cure than on a warm sunny day.
High-Density Polyethylene (HDPE) is a plastic resin created by a small hydrocarbon copolymerized with ethylene. The first known production of HDPE occurred in the 1930s in the United Kingdom. However, it still took 20 years to gain popularity within the U.K. before gaining ground in the United States.
HDPE is a durable material versatile enough for many different construction applications. For municipalities, HDPE is often found as storm sewers, cross drains, and underdrains.
The HDPE material is resistant to tuberculation, sediment deposits, and corrosion. It is abrasion and freeze-resistance. It is considered eco-friendly, as it is recyclable when replaced. Due to its durable design, HDPE has a life span of 50 to 100 years.
While HDPE is an ideal choice for municipal construction, there are some disadvantages. To seal joints on HDPE lines, workers must use heat to fuse them. This can be difficult in some areas to get the line adequately bonded. There have been some reports of aging resistance being less than optimal for some situations. Also, if the lines are under stress, they will crack.
From old piping to new plastic, each has its benefits and downsides. There is no perfect plumbing solution that meets every single need. Cost, matching the appropriate material to the conditions of the project and the lifespan of the chosen pipe product all must be considered. Understanding the advantages and disadvantages will help project managers to choose the best materials for the job.
Written by Denise Sullivan | Technical Writer @ Trenchlesspedia
Denise Sullivan is an accomplished freelance writer from Louisiana, with a Associate's Degree in Journalism from Eastern Oklahoma State College. She also graduated from East Central University with a Bachelor's in Biology. Denise began her writing career writing operations and maintenance manuals and software utility manuals for flight simulators. Since, she has expanded her writing to a broad spectrum of topics.