Pre-commission cleaning of pipework can ensure the performance and longevity of open and closed water systems. But, when is it applicable and what are the requirements, benefits and possible pitfalls of the procedure?
Chemical cleaning is not compulsory for all systems, although the majority of systems will benefit from some form of chemical cleaning to supplement clean water flushing
But pre-commission cleaning is a standard requirement for new closed water installations under the guidelines published by BSRIA.
The two guidance documents relating to pre-commissioning cleaning published by the body are:
BSRIA BG29:2012 Pre-commission Cleaning of Closed Systems
Newly fabricated and installed closed water systems can harbour mill scale, jointing compound and a catalogue of other debris associated with factories and building sites.
Systems that are not properly cleaned of these contaminants prior to use can be subject to the unwanted build-up of sludge and bacteria over time. This, in turn, can cause corrosion, blockages and biofouling leading to inefficiencies, leaks and other costly system failures.
Ineffective cleaning can cause suspended solids, biofilm, grease and oil to remain in your system, producing an immovable layer on the pipework. This will mean inhibitors will not reach the metal surface and, therefore, cannot prevent future corrosion.
In their guidance the BSRIA state the following:
“When cleaning existing systems, the history, pipework conditions and reasons for the flushing or cleaning need to be assessed to determine the likely outcome before works proceed. It is generally the case that parameters set out in BSRIA 29/2012 can be used as a target for water quality and that any deviation should be logical based upon the above assessment.”
1. Plan your pre-commission cleaning to address four main types of contaminants – these are the elements that, if unaddressed, can cause poor performance, system failures and costly maintenance further down the line,
2. The type of pre-commission cleaning required will be influenced by:
3. Plan for the nine possible stages of a system clean, but follow advice to determine what your system requires :
4. Understand the overall success of a system clean is dependent on the thoroughness of each recommended stage of the clean. Ensure each one is conducted for the required duration and at the appropriate intervals for best results.
5. Test for success. To be sure your clean has been successful, test for bacteria level. Take water samples from representative system extremities and low points. Check for and maintain system pressure and do not contaminate sample results by topping up or replacing water loss. Don’t forget, the introduction of a body of fresh water could re-introduce contamination
6. Remember, pre-commission cleaning can fail if:
7. Throughout the process you need to ensure your system is continuously monitored so that changes can be tracked, recorded and the appropriate action taken to rectify issues. Use Hevasure to independently monitor conditions before, during and after and cleaning procedure to ensure that oxygen levels are low and corrosion is under control.
There is no ‘one size fits all’ method for pre-commission cleaning. Every water system is different in its setting and design, as well as its intended use. Take advice on the best approach for your specific system and follow the recommendations carefully to ensure its future optimal performance and longevity.