choose the right piping material

Choosing the right piping material

A large component of reducing compressed air system energy costs and increasing plant efficiency is choosing the right air distribution system. Piping is quite often overlooked when it comes to optimization projects. It’s also one of the first project costs cut when an installation budget needs trimming. Truth be told, piping material selection greatly impacts pressure drop, air quality, and leak load. Here’s an overview of common piping materials and some considerations to keep in mind when selecting pipe for your installation.

Common piping materials

The most common piping materials include stainless steel, aluminum, copper, galvanized iron, black iron, and PVC. The table below lists the advantages and disadvantages of each. PVC is included in the chart because it’s commonly used, but it’s not a material we would recommend using because of the safety concerns associated with installing it.
 
Generally speaking, aluminum and copper would be the best choices since they are not prone to build-up and will provide years of low pressure drop air delivery. Also, aluminum is available as a system—complete with perfectly matched connectors for leak-free design.
 
Copper is also a solid choice, however installation does require an open flame and quality brazing to prevent leaks. The material cost can also be high.
 
Stainless steel is not prone to build up or leaks, but it is very expensive and really only called for in specialty applications—if you need it, you’ll know.

Piping installation considerations

When selecting piping for an installation, consider the following:
 
  • Material cost: Will you need to purchase special tools to install or maintain the pipe?
  • Installation: Will you need to outsource? Also, do you anticipate growth or making changes to your piping? (Aluminum pipe can be disassembled easily and adding in drops to accommodate growth is fast. Copper is not as quick to install as aluminum, but it is still faster than threaded pipe).
  • Air quality: Can your process tolerate contamination from rust or other build-up flaking off from the pipe? (Black iron and galvanized iron are notorious for this).
  • Maintenance: Do you have the time and manpower to continually monitor and fix leaks that can occur with materials that are more susceptible to rusting at joints and leaking? (A concern for black iron and galvanized iron. Also, the brazing on copper should be inspected regularly).
So when it’s time to choose piping materials, look at more than the cost of the pipe. Think about your system needs today and long term. Looking ahead can help you make the right investment at the right time.
Material Advantages Disadvantages
Stainless steel No rust, good air quality Labor-intensive installation
Smooth interior - low pressure drop Expensive materials
Aluminum Corrosion resistant Limited pressure ratings
Lightweight Material costs
Easy to install
Lower cost of ownership
Copper No rust, good air quality Requires quality brazing to prevent leaks
Smooth interior - low pressure drop Susceptible to thermal cycling
Installation requires open flame
Galvanized iron Moderate material costs Exterior is often coated
Readily available in multiple sizes Labor-intensive installation
Some rust protection Rough inside promotes contaminant build-up and creates pressure drop
May rust at joints and leak
Black iron Moderate material costs Labor-intensive installation
Readily available in multiple sizes May rust and leak
Rough inside promotes contaminant build-up and creates pressure drop
PVC Lightweight Lower safety
Inexpensive Not compliant with certain codes in certain areas
Carries static charge
Subject to bursting
Adhesives not compatible with compressor oils

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