Air Scouring - Case Study

1. The Brief

Indepth were commissioned to carry out water mains cleaning to a 100mm pipeline over 500m with heavy discolouration and bio-film to the internal pipework using the air scouring method.

The objective of the survey was to; improve water quality by cleaning using air scouring and removing bio-films from the internal pipework

2. Procedures And Methodology For Leak Detection

The following briefly outlines the procedures followed during the course of the project.

Pipe Scouring Using Air Treatment Units

A roadside compressor delivering air to an air treatment unit, which is then injected into the pipe for scouring. These mobile units incorporate aftercoolers, filtration systems, pressure regulators and hoses to supply air suitable for air scouring water mains. Pressure can be regulated not to exceed the normal working pressure of the existing mains. It is manufactured in accordance with the specification of the Water Research Council to deliver filtered air which meets the air quality standard BS EN12021. The PS125 has a capacity of 125cfm at 7 bar and the PS250 has a capacity of 250cfm at 7 bar.

Air Scouring Set Up

InDepth Water Management Air Scouring Process

Air Scouring of water mains is an extremely effective ‘non-aggressive method of cleaning water mains. From 75mm diameter to 300mm diameter, with typical cleaning lengths ranging from 100 to 1000 metres.

Air scouring works by using filtered ‘oil free’ compressed air, injected into the mains via a hydrant to propel a small volume of water at high velocity. Air and water are ejected together with any suspended solids from a hydrant at the end of the length being cleaned. This system has the effect of achieving water velocities high enough to carry deposits in the water stream.

Provided that a continuous supply of compressed air and water is in the right proportions, discrete slugs of water are formed in the main and are driven along at high velocity by the compressed air. It is the slug flow system that enables solids to remain suspended in the water over the long distances being cleaned.

Benefits Of Air Scouring

  • More effective at removing loose deposits than flushing
  • Mains up to 300mm in diameter can be cleaned
  • Long lengths (up to 1000m) can be cleaned in one go
  • Mains excavation is not required (unless for install of HY injection point)
  • A mixture of air and water penetrates and dislodges material that is unreachable by flushing, proving effective in the removal of animals
  • Shorter purge lengths and higher velocities can be successfully used in the removal of bacteriological slimes
  • More cost-effective than swabbing


InDepth Water Management Air Scouring


InDepth Water Management Air Scouring


  • Full cleaning of pipework achieved
  • Discolouration of water removed to crystal clear water
  • No damage was caused to the pipework
  • Local customers comment “I have never seen this water as clean in my life, I am putting on a whitewash.”

Get In Touch

InDepth Water Management is available for 24/7 emergency call outs. This ensures you peace of mind as one of our trained engineers will call out to you as soon as possible.

For Air Scouring, call InDepth Water Management on 0818 77 22 22