Compressed air is one of the most misunderstood utilities in industry. Case in point – yesterday I overheard a conversation at a hardware shop between a customer and a sales person.

Customer – “I would like a compressor, 200 liters.”

(Attendant checks to see if such a compressor was available and proceeds to give a price)

Customer – “What is the compressor motor HP?”

(Attendant does not know and has to confirm the details)

This conversation may not seem out of place if you are not a compressor professional but to those in the industry it sets alarm bells ringing.

This conversation leaves out the most crucial information about sizing and selecting a suitable compressor. There are critical questions that need to be asked to enable customers procure the right equipment and to ensure their needs are well served.

What is the application?

  • The application will guide the air quality requirements for example, the need for a dryer, filters or an oil free compressor. The application will also guide the choice of compressor type.
  • To clarify, screw compressors are more suitable for continuous operations such as those in manufacturing and piston for intermittent use such as petrol stations or workshops.

What are the pressure and flow requirements?

  • This would be the equivalent of the load the compressor is expected to serve and is the most important information in determining the appropriate size of compressor.
  • This information can be found by checking the data plates of the equipment that will be using the air or by carrying out flow and pressure measurements.

Back to the customer that I listened to…

It is possible that they may have found a solution to suit their application, and it is also possible that they procured an item that was oversize or undersized for their needs.Both scenarios are quite undesirable, and can be avoided.

Unlike before, compressors are now available over the counter at many hardware shops around the country.

This shifts the responsibility from the hardware vendor, directly to the customer to understand their application well enough to know what the requirements are and what specific questions to ask to ensure they get the right solution.

On the other hand, if the vendor is informed then they may as well be the solution provider and seek to advise customers accordingly. However if both are uninformed as is proving often the case, it is the perfect recipe for expensive mistakes.

This encounter raises the following critical questions:

  1. Are we are as informed about compressed air as we would like to believe?
  2. What energy efficiency opportunities are we missing due lack of information?
  3. Have we invested in compressed air training to build competence in this subject?

By Eng. Mathew Waita Mwenga

Eng. Mathew Waita Mwenga is the managing director at Ren Engineering Solutions and is very passionate about energy efficiency with a special interest in compressed air solutions. He may be found on +254 715 833 628 | |