Pre-Commission Cleaning (Heating & Chilled Systems)


What’s the Issue?

When will my newly installed or refurbished circuit system require pre-commission cleaning?

How do I know what types of chemical corrosion inhibitors and disinfectants are suitable for my system?


What is your obligation?

BSRIA BG 29/ 2012 states that pre-commissioning cleaning should be undertaken within the following:

  • In any new installation of heating and chilled closed water systems.
  • In systems showing an indication in corrosion activity.
  • In systems showing a deterioration in water quality.
  • In systems showing high iron levels.
  • In systems subject to alterations or refurbishment works.
  • In systems subject to an adverse sample result where a remedial action maybe required, i.e. flushing and dosing.


If pre-commission cleaning of pipework is not completed successfully, or at all, then the systems efficiency & life expectancy can be seriously compromised. It could also cause you to face unnecessary running costs and replacement of expensive parts if ignored. Microbiological issues could also occur and become a serious problem in the presence of retained debris which can become baked onto the pipe walls and surfaces. After time, this could lead to failure of the fittings and equipment, leakages and system blockages and heat loss.


How we can help?

As long standing members of BSRIA, Atom Water Treatment have extensive knowledge and experience within pre-commission cleaning works, and over the years have worked with some of the challenging and most complex systems around. We have a very good understanding of closed system agents and inhibitors and their use for various systems. Not only are we able to supply the pre-commission cleaners and inhibitors for you, but we are able to undertake the pre-commissioning works ourselves upon your behalf, if required. Our services are delivered utilising the latest high performance water treatment equipment and chemicals to ensure all works are undertaken in accordance with the correct guidelines and to a high-quality standard.

Contact us for a free no obligation quote including any further advice and guidance you may require.

Book a Consultation

or call the office

0203 597 5035

Pre-Commission Cleaning of new heating & chilled systems is paramount before being brought into service. It is essential that the removal of all grease, oil, biofilms, corrosion deposits, and general debris is removed from the system to present a clean metal surface on which the corrosion inhibitor can act to prevent corrosion of the system over its lifetime.

During the construction period, the system is left open to a build-up of debris, microbial slimes, biofilm and other types of fouling which can prevent the corrosion inhibitor from doing its job and in return will not be able to prevent the system from corrosion. During the pre-commission cleaning process a chemical cleaner should be utilised to ensure the system is left clean and clear, a raw flush of the system is not sufficient to remove these types of contaminants.

Due to the equipment used over recent years, pre-commission cleaning has never been more paramount. This is because the equipment used is now more susceptible to blockage at strainers, control valves and small bore pipework. System contaminants need to be removed by chemical cleaning and high velocity flushing, this will then allow the on-going water treatment regime to work at its most effective to prevent corrosion and microbiological fouling of the system.

Pre-Commission Cleaning of pipework systems should be undertaken in accordance with the guidance of BSRIA BG 29/ 2012 and full records of cleaning should always be kept and include all parameters detailed within this standard. Any sampling that is performed during the course of these works should be undertaken in line with BS8552 and a full set of the results should be retained.

Older closed heating & chilled systems can with age, become very un-reliant and inefficient, especially if they have been subject to poor water treatment regimes. Atom Water Treatment have seen many cases of this in the past and as a result have seen systems suffer from blockages, leakages and reduction in heat transfer efficiencies. By introducing a correct and effective water treatment regime suitable for your system, then this can prevent these problems, thus causing less time and expense spared.

When taking on a pre-commission clean, there are often various things to consider.

  • Is an adequate water supply and is there a double-check non-return valve fitted?
  • Will the pump have a suitable and reliable power supply?
  • Do I have the correct drainage and will I need a discharge licence?
  • Have I understood and carried out the correct system considerations prior to commencement of the works?
  • Have I adhered to the correct British standards and correct guidelines?
  • Have I adopted an effective chemical cleaning programme?

It is also important that an appropriate timescale is agreed between the client and the water treatment provider and that full risk assessments and method statements are provided.