Plumbing pipes for residential and commercial buildings come in a variety of materials, and each type has its advantages, limitations, and particular usage. Therefore, it is important to know all the pipe varieties in the market before making an investment in plumbing installations. The most commonly used materials are copper, PVC, CPVC, and PEX.
This article will provide an overview of the most popular piping materials. Like in many engineering decisions, the best option changes depending on project conditions - each material has pros and cons.
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Copper has been the traditional material for plumbing since the 1960s, due to its durability. Since then, other materials have been introduced in the market, but copper is still one of the best materials for plumbing. The main drawback of copper piping is its high cost, and it requires soldering and additional fittings. Due to its high price, copper piping is prone to theft when exposed or easy to access.
-Not prone to leaks
-Proven standard for reliability since the 1960s
-Does not pollute water
-Old pipes can be recycled
-Expensive: Around $300 for 100 ft
-Old installations may contain lead-based solder
-Even though old copper pipes can be recycled, copper mining and manufacturing cause significant environmental damage. Thus, copper is not considered a green material.
-Interior hot and cold wall supply lines - very thin walls(M) and medium thickness(L)
-Underground service lines - thickest walls (K)
-Hot and cold drinking water supplies
-Refrigerant lines for HVAC systems
Polyvinyl Chloride Piping (PVC)
PVC is a white piping material commonly used in plumbing applications, and it comes in two sizes called schedules 40 and 80. Schedule 40 is the most commonly used, while schedule 80 has a thicker wall and is stronger. A table created by the American National Standards Institute (ANSI) provides information of the outside diameter of all schedules for a given pipe size to be equal.
-Rust and corrosion resistance
-Sustains high pressure water
-Easy installation, requires no welding or metal work
-Versatile, it is available in multiple sizes and it has a variety of fittings
-Strong and durable
-Cannot be used for hot water transportation - PVC warps with heat
-Degradation when exposed to UV light
-Not safe for drinking water
-Indoor and underground plumbing
-Drain lines of sinks, toilets and bathtubs
-Main water supply lines
-Storm drainage systems
Chlorinated Polyvinyl Chloride Piping (CPVC)
CPVC are PVC pipes with extra chlorine. Basically, it is a PVC pipe that can be used to carry hot water and is safe for drinking water. Compared with copper pipes, CPVC pipes are smooth and produce little water noise. They are insulated to prevent energy loss, more flexible than metals, and fire resistant.
-The extra chlorine makes it safe for drinking water
-Can transport hot water
-Increased flexibility, compared with PVC and metal pipes
-All the benefits of PVC, plus added durability
-Pipes split when frozen
-More expensive than PVC
-CPVC manufacturing is highly polluting
-Hot and cold water supplies
-Hot water drains
-Waste and water disposal pipes
Cross-linked Polyethylene Piping (PEX)
PEX pipes are considered one of the biggest innovations in plumbing. PEX is an extremely flexible pipe similar to a hose, which can bend around edges and obstructions if needed. In addition, it does not require glue because piping connections use compression fittings.
PEX can be adapted for existing piping, including copper, making it a great choice for reparations and retrofits. PEX has a higher upfront cost than PVC, but it requires minimal maintenance and is easily installed. PEX pipes and fittings have been used for about 30 years but their popularity has increased significantly in the last decade.
-Freezing resistant, thanks to the material’s ability to contract and expand
-Studies for potential contamination of drinking water are still taking place, but it has been approved in states with stringent environmental regulations
-The fittings used require a special tool
-Cannot be directly connected to a hot water heater
-Cannot be used in outdoor applications, since UV rays can cause damage
-Hot and cold water supplies
-Remodelations, where it is snaked into walls
-Areas with low ventilation where using glue is dangerous.
Other Piping Materials
There are additional materials that were used or can be used in plumbing systems, but they are less popular than the types described above.
Galvanized Steel Pipes
Galvanized steel pipes were used several years ago, but not anymore due to their negative effects:
-Internal rusting in small diameter pipes, due to zinc coating
-Can get clogged over time
-Lead can be released through corroded pipes
Galvanized steel pipes are used mostly in grey and non-potable water drains.
Stainless Steel Pipes
Stainless steel pipes are durable but very expensive, even more than copper pipes. They are used in areas prone to corrosion, such as coastal environments. Stainless steel piping offers the following advantages:
-Strong and corrosion resistant
-Pipes can be flexible or rigid
-Available in several sizes and lengths
Cast Iron Pipes
Cast iron pipes are usually manufactured as a bell and spigot type, and they are the heaviest of all plumbing pipes. They are very durable, and allow the use of PVC to replace parts of a cast iron piping system. However, cast iron pipes are very heavy, and require additional supports during installation.
Some common applications of cast iron pipes are water distribution systems and underground installations, such as the main pipes on drainage and sewer systems.
Grey Plastic Polybutylene Pipes (PB)
This is an inexpensive and easy to install plumbing material, but unfortunately it is prone to leaks.
High- Density Polyethylene Pipes (HDPE)
HDPE is a flexible material that resists corrosion and has a long life span. However, due to these benefits, HDPE is more expensive than PVC.
Brass is an older option that was used for plumbing even before copper. When brass pipes are being used, it is critical to ensure that the alloy does not contain lead. Red brass pipe is considered the best type of brass pipe, since it contains high percentage of copper. Brass piping is commonly used in water supply lines, water removal drains, pump fittings, water tanks and wells.
-Highly resistant to corrosion
-Soft material that allows tight seals
-Similar benefits as copper
-Long service life
-May contain lead
Polypropylene Pipes (PP)
Polypropylene pipes are rigid plastic pipes, similar to CPVC. However, they are not joined with chemicals, and instead heat is used to adhere mating ends. PP is commonly used in Europe, has not received much attention in the United States. PP piping is durable, safe for human health, and considered an environmentally friendly material. The main drawback is a complex installation process that requires specialized tools.
Some common applications of PP piping are hot and cold water supplies, and drains.
With the wide variety of piping materials available, choosing the right plumbing pipe for a project can be a challenging decision. The best recommendation is getting in touch with professional plumbing engineers, and learning about each material available and its features. This way, you can make sure that your plumbing installation uses the most suitable material for your project conditions and budget.