Pre-Commission Cleaning

The pre-commission cleaning of hot water heating and chilled water systems has become more important over recent years, due to the equipment used being more susceptible to blockages at strainers, control valves and small bore heat exchangers.

System contaminants such as mill scale, jointing compounds and fabricating debris need to be removed by chemical cleaning and high velocity water system flushing, which will then allow the on-going water treatment regime to work effectively in preventing corrosion and microbiological fouling.

Older systems that have accumulated deposits due to lack of the correct water treatment can be cleaned by a similar method.

New Water Systems

New installed pipe-work can frequently have debris, such as mill scale from steel pipe-work, oil and grease and welding and soldering residues contaminating the system. Flushing of the pipe-work with water alone is not sufficient to remove contaminates which adhere to the surfaces of the pipes.

The Green Water water system cleaning service follows the recommendations of BSRIA, which consists in general of the following steps:

  • Inspection of the water system and identifying ideal positions for the flushing points, if these have not already been allowed for by the pipe-work contractor
  • Identifying whether the pipe-work contractor is to carry out water system flushing prior to chemical cleaning
  • Establishing how the flushing velocities are to be achieved i.e. pumping requirements
  • Flushing the system with water at high velocity
  • Adding a chemical cleaner to the system water to remove oil, grease, corrosion deposits and to mobilize any suspended solids present
  • Biological flushing of the system may also be necessary
  • High velocity flushing of individual circuits of the system to achieve the flushing velocities recommended by BSRIA and removing excess chemical cleaner
  • Testing the water for the presence of iron and suspended solids, etc.
  • Addition of a corrosion inhibitor for long term protection
  • Installation of a side stream hydro-cyclone filter to remove small amounts of suspended solids after commissioning
  • Regular service visits to chemically test the water and maintain the correct inhibitor level and to ensure that bacterial levels are within acceptable limits

Existing Water Systems

Existing heating or chilled water systems that are being extended, or may be experiencing poor heat output due to low flow rates, can be chemically cleaned by a similar method. Special precautions should be made to ensure that corrosion products that may be loosened by the water system cleaning process do not cause blockages. The experience of Green Water Services with our in depth knowledge of the problems encountered, will ensure that our customers receive the correct advice complying to the HSG 274 guidance.

Please contact us for more information regarding our BSRIA flushing and our water system cleaning service. We are located in Leeds, Croydon, Swadlincote and Burton-on-Trent, however our services are offered nationwide.

Green Water Services also specialise in Legionella Risk Assessments, water tank cleaning and cooling tower cleaning, so please give us a call to learn more about these treatments.


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