Homes and businesses have a massive network of plumbing pipes running through the structure. From bringing water to your sinks, showers and bathtubs to carrying waste out to the sewage system, each pipe has a different function with different requirements. Whether you are considering hiring a plumber or tackling a home plumbing DIY project, it is a good idea to be familiar with the different types of plumbing pipe materials.
PEX:
PEX (cross linked polyethylene) is a common plumbing pipe material as it creates durable piping that is often used for water supply lines. This material is rigid enough to handle the pressure of your water supply, but it is also flexible enough so that it can be weaved through walls, crawl spaces, ceilings and basements.
PEX pipes are similar to a hose, as it can bend around any obstructions or edges. It is also flexible enough to be used with existing pipework such as copper. This makes it a good choice for retrofits and repairs.
Another reason why PEX is so popular is that it is one of the least expensive types of piping. It can be easily cut or joined together using compression fittings, eliminating the need for gluing or soldering. PEX has a long lifespan and it can withstand extreme temperatures. This means that not only can it be used to transport cold and hot water, but it will prevent corrosion or rust leaching into your water.
One potential downside to PEX is that it cannot be used in outdoor applications. The plastic is vulnerable to UV radiation damage. Additionally, some types of PEX piping may affect the odor and taste of water, but the concerns about contamination have been investigated and dispelled. Although PEX is costlier compared to PVC, the installation costs tend to be lower and there is minimal maintenance, making it a preferred choice.
PVC:
PVC (polyvinyl chloride) is a type of plastic that is commonly used for waste lines connected to toilets, shower drains or sinks. It is popular as it is not only relatively inexpensive and lightweight, but it is easier to work with in comparison to galvanized steel. It can be cut to size with a hacksaw, with connections made with piping glue.
PVC piping has a smooth inner lining that improves the resistance to blockages and can protect against the buildup of sediment. PVC can also handle high water pressures and unless it is subjected to some form of damage, it can last a lifetime.
There are two sizes of PVC pipes common in plumbing which can be used for a variety of purposes including drain lines, indoor plumbing, vent stacks, storm drainage, high pressure pipes and underground plumbing. Schedule 40 is most commonly used as it has a lower price point and thinner walls. Schedule 80 is more durable due to its thicker walls, but this comes at a cost.
The main drawback of PVC is that it cannot be used for hot water. When it is exposed to hot water, it can warp or possibly melt. Additionally, while it meets the American National Standards Institute requirements, there are some concerns about toxicity. There are some concerns that PVC could introduce chemicals into water, specifically polyvinyl chloride, which has the potential to cause reproductive and respiratory issues. For this reason, many PVC plumbing pipes are banned for use in transporting drinking water in some states.
CPVC:
CPVC (chlorinated polyvinyl chloride) is another member of the PVC family, making it a cousin of PVC. The key difference between PVC and CPVC is the chlorination. This makes CPVC able to withstand temperature differences that PVC pipes cannot. CPVC can be used for transporting hot water as it can tolerate temperatures of up to 200ºf.
CPVC does have the same restrictions for outdoor use, as sunlight and UV damage can still break down the pipe material. It can also be vulnerable to splitting at freezing temperatures. Additionally, CPVC is more costly compared to PVC. This material is not recyclable and the manufacturing process is considered to be highly polluting. Hence, CPVC is avoided for applications where the environmental impact of the project is a priority.
Polypropylene:
Polypropylene or PP creates a rigid, plastic pipe which is similar to CPVC. This material is more commonly used across Europe and has not received a great deal of attention in the US market. PP is considered an environmentally friendly material, providing a durable pipe that is safe for humans. It is most commonly used for cold and hot water supplies and drain lines.
The main drawback of PP is that the installation is quite complex and requires specialized tools. Rather than being joined with chemicals, heat is used to adhere the mating ends of the pipe.
ABS:
ABS (acrylonitrile butadiene styrene) looks like PVC, but it is actually made of thermoplastic resin. It is typically black and can be more durable, as it is resistant to cold temperatures. It is mainly used for drain and vent lines, and it is limited to indoor use as it can still have damage issues when exposed to UV.
Another important thing to note is that ABS pipes can be noisier compared to other types of plumbing piping. If you’re sensitive to noise, you may prefer another type of pipe in your home.
Polybutylene:
PB or polybutylene was a popular choice for plumbing pipes between the late 1970s and 1990s. It was considered a “futuristic” pipe material made from a plastic resin. It was considered as a replacement for copper, as it was cheap. Unfortunately, due to being prone to leaks at the joints, PB waned in popularity.
HDPE:
HDPE (high density polybutylene) was developed due to the limitations of PB pipes. This material is flexible and has corrosion resistance. This along with its durability makes HDPE suitable for a variety of plumbing applications. The main drawback to this type of pipe is that it is far more expensive compared to PVC.
Copper:
Copper has been a staple in plumbing piping for decades. It has been the traditional material for plumbing since the 1960s. Copper has a lifespan exceeding 50 years and it can be used for showers, sinks and other fixtures. Copper piping is a popular choice as it is resistant to corrosion and can help to protect water quality as bacteria cannot thrive inside copper pipes.
Copper can also handle hot and cold water along with high water pressure. There are numerous grades of copper piping, with Type K used for underground service lines as it has the thickest walls, while Type M is more commonly used in wall supply lines and has the thinnest walls.
Copper is also recyclable, so it is considered a more environmentally friendly choice. It is important to note that while old pipes can be recycled, mining and manufacturing new copper does cause environmental damage, so copper is not truly considered a green material.
There are some drawbacks to using copper. Copper is not only expensive, but it is rigid, making it more difficult to use in a cramped space. Fortunately, there are soft copper options, which are malleable and can be used in soft runs where flexibility is needed due to tight spaces. Additionally, copper pipes do require additional fittings and soldering, which can make installation more expensive. Old copper pipe installations may have used lead solder, which could create water contamination issues. Copper can also be a temptation for thieves, due to its value, particularly when the pipes are exposed.
Flexi:
Flexi or flexible pipe is typically made of stainless steel. It is most commonly used for connections to appliances including sinks, toilets and water heaters. But generally, flexi pipe is not permitted for applications inside walls or under floors.
Flexi piping is available in various sizes and lengths. It is typically quite durable, but it can fail after years due to wear and tear. It is also a little on the expensive side, but on most projects, you won’t need to use a lot of this piping.
Stainless Steel:
Stainless steel is a more expensive piping choice compared to copper, but the high price point does indicate a high level of quality. Stainless steel piping is corrosion resistant and strong. Due to its ability to resist corrosion, stainless steel tends to be preferable in areas where the pipes may be susceptible, such as in a coastal community.
There are both rigid and flexible stainless steel piping options in a variety of sizes. These can be fitted together with couplings.
Galvanized Steel:
Galvanized steel pipes are a corrosion resistant and rigid option that is used for water supply, drainage and other plumbing purposes. This was once the material of choice for use in residential plumbing applications with a zinc layer coating the pipe to prevent rusting. But, today, this is far less common as galvanized steel may compromise water safety due to rust building up and entering the water over time.
The main issue with galvanized steel is that lead can be released as the pipes begin to corrode. Additionally, due to the zinc coating, the pipe diameter can be reduced, increasing the risks of clogging. Galvanized steel is also very heavy, which creates limitations on the applications where it can be used.
You may still find galvanized steel piping in your home as their sturdiness makes them an ideal material for gas supply lines.
Cast Iron:
Like galvanized steel, cast iron pipes were common in both homes and commercial properties throughout the early 20th century. Cast iron pipes are rarely used in new construction projects and if you have an older property, you may be able to identify the presence of cast iron pipes by their rigidity and dark gray color. It is most commonly found as sewer or drainage pipes.
Cast iron is one of the heaviest plumbing pipe materials. These pipes typically feature a bell and spigot, but additional supports need to be included in the installation plans, reducing the feasibility for many applications. Cast iron does have a long lifespan and is very durable, but it is prone to rusting and corrosion. This means that over time, the ability to deliver a clean water supply is compromised. In recent decades, copper or PEX piping has replaced cast iron for residential plumbing applications.
Black Iron:
Black iron was not meant to be used for plumbing pipe applications, but at one time it was a popular material for water supplies. Today, black iron pipes are only used to convey propane or natural gas. It can also be used for fire suppression systems such as sprinklers, as it is highly effective at resisting extreme heat.
Brass:
Another older material that can be found in plumbing installations is brass. Brass was used before copper as it is highly resistant to corrosion and is heat resistant. Brass is a soft material, which allows for tight seals and it can offer a long service life. Brass piping is most commonly used in water tanks, wells, pump fittings, water removal drains and water supply lines.
The main issue with brass pipes is that it is crucial that the alloy does not contain lead. Any lead in the material could lead to leaching into the water, leading to serious health implications. The best option is considered to be red brass piping, which contains higher amounts of copper and no lead.
Summary:
With such a wide variety of materials available, choosing the right pipe for your plumbing project can be challenging. It is important to note that there may be state laws in place which determine which materials can and cannot be used in certain applications.
If you are planning a DIY project, it is crucial that you understand any state or local laws in your area. The best idea is to speak to a professional plumbing specialist. An experienced plumber can help you to learn more about the features of each material and any applicable laws so you can find the most suitable materials for the conditions and budget of your project.
