How to Calculate the Dimensions of Pipes for Compressed Air

January 23, 2022

With an air compressor, you can connect pneumatic tools to the unit and suck in pressurised air for numerous other applications. However, these efforts would hardly be effective without the pipes with the sufficient dimensions. The following article explains how to determine the pipe size needed for a compressed air system. 

How to determine the correct size of the pipe?

In order for a compressed air system to have a healthy air flow, it is essential to minimise pressure loss levels. If the system is specially designed for high-power performance, the pressure loss should be practically non-existent.

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The size of the hose required for an air compressor depends on two factors: the distance of the application and the volume of air transported to the end point. If the air tools are placed in the middle of the factory, you will need a pipe of a different size than you would for an application located one meter away from the air compressor. 

What is the best hose for compressed air?

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In order for a pipe to minimise air leakage it needs a suitably wide diameter to transport a specific flow volume through a long extension. However, for that same volume, a smaller diameter may be sufficient to travel a shorter distance between the compressor and the point of use.

You must then define the pipe size at compressor pressure and application usage point. It can be difficult to determine the amount of airflow you will have in each arm of an aerial distribution system.

For some applications, air usage may flow at a normal and even speed. This tends to be the case with large systems consisting of various branches that supply air to different machines and tools. In smaller systems, wave flows often occur, especially if air is sent to numerous applications at once. 

How to size a compressed air pipe

In applications that require stable airflow, the compressor will produce a volume of air per minute in relation to its power. If the compressor has a high power, it should produce a greater capacity, with greater volume of air per minute. 

Most often, the hose connected to the air compressor is selected depending on the diameter of the machine outlet. Although it may seem intuitive to correlate the diameter of the pipes with the outlet diameter, this can lead to errors within the system.

Choosing the appropriately sized compressed air hose

According to some technicians working with air compressors, the air velocity within a series of system pipes should vary between 6 and 9 m per second. This minimises any pressure drop that might occur. 

With the same pipe length, pressure losses can be reduced by using pipes with smooth interiors. With these materials, you can use pipes of smaller size and higher air velocity while still maintaining a minimum pressure drop. However, if the piping system contains tight curves of 90 degrees or more, a greater pressure loss may occur due to these restrictions.

How to determine the necessary pipe dimensions

To find the right pipe sizes for the compressed air system, it is necessary to take into account the maximum demand for air at the minimum operating pressure of the system. You should consider the worst-case scenario that might occur during a momentary use cycle. Such use is generally created by air storage at the point of use. Therefore, it will not be necessary to change the pipes throughout the structure just to check the situations of momentary use.

How to determine the size of the hose needed for compressed air

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To know the pipe size needed for the air compressor, you need to know the minimum operating pressure for the units. This figure should be based on the minimum requirements specified by the manufacturer. Ideally, the distribution system of an air compressor loses virtually no pressure between the connection points of the units and each pneumatic application.

Compressed air pipe sizing

A mistake that some users make is assuming the energy lost in overpressure due to leaks in pipes is a safety in the case of occasional uses of high-end applications. The fact is that the performance and longevity of your compressed air system is at stake. The price you should pay to replace your pipes with suitable dimensions for your system could be a minimal expense compared to the costs you can have on an annual basis derived from energy waste and air leaks. 

If you want to have piping that meets all possible pressure demands, consider the layout of your system. While it might seem useful to buy the largest pipes possible, this could be a waste of money for oversized pricing. Instead, the placement of an appropriate set of pipes in relation to the compressor and pneumatic tools must be considered. 

Correct compressed air hose size for specific applications

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With a reciprocating or rotary screw air compressor, you can perform a lot of tasks as long as you have the right tools and an optimal connection. For most single applications, only a fraction of the air compressor capacity is required. Up to pipes of 30m length, a diameter of half an inch will be enough to facilitate the speed and air pressure necessary for the following applications:

  • Painting
  • Perforation
  • Greasing
  • Modeling
  • Nailing
  • Cutting and sawdust
  • Polishing and sawdust
  • Metalworking
Compilation of AirNET piping products
Regardless of the final application, it is important to know the dimensions of the pipes needed by the compressed air system to meet the various needs. Whether you run a workshop or run a pressing plant, it's crucial to have a compressor that can power all your tools and also have the right hoses to facilitate air pressure and speed.