Pre-Commission Cleaning

The importance of Pre-Commission Cleaning and subsequent water treatment cannot be over-emphasised. The significance of this is shown through the existence of several British and European standards; and guidance documents issued by various industry bodies.

LCS can carry out your PCC requirements selecting from a range of pre-commission cleaning and flushing agents which can be tailored to the requirements of the system.  The product range includes biocidal flushing products, effective inhibitors, biocides and biodispersants. 

Typically for larger systems Consent to Discharge Trade Effluent would be required but don't worry - LCS would do this for you.  Just be aware that the process can take several weeks and it's illegal to discharge trade effluent to waste without this consent.

Effective pre-commission cleaning of new systems is absolutely critical. Unfortunately, the important nature of this operation is often overlooked or undervalued. The objective of a pre-commission clean of a closed system is to remove all grease, oil, biofilm, corrosion deposits, flux and jointing compounds and general debris from the system. This will then present a clean metal surface on which the corrosion inhibitor can act to prevent corrosion of the system over its lifetime - if a corrosion inhibitor is not direct contact with the metal surfaces, it cannot inhibit corrosion!

If suspended solids, biofilm, grease and oil remain in the system these will produce a layer on the pipework which will mean that the inhibitor cannot reach the metal surface and thus cannot prevent corrosion. A raw water flush does not remove these layers of contaminants from the pipework surface, a chemical cleaner is required.

It is often the case that unrealistically short time periods are given for pre-commission cleaning as the critical nature of this operation may not be fully understood. Different chemical products have varying minimum contact times. For example, BSRIA BG50 states contact time should be anything from ‘12 hours to 3 weeks’, so if the available contact time for the cleaner is short, LCS can advise on the appropriate product and contact time to work effectively within the time available, but please be aware that pre-commission cleaning may not be fully effective, or even possible at all, in a very short window!

If particles of installation debris remain in the system, erosion corrosion may result under the velocities of normal operation. Some jointing compounds contain chloride which in itself may accelerate corrosion of certain metals. For these reasons the significance of a thorough pre-commission clean carried out over a ‘realistic time window’ cannot be over-emphasised.

The pre-commission cleaning of hot water heating and chilled systems has also become more critical over recent years. This is mainly 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 flushing. This 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 a lack of correct water treatment can also be cleaned using a similar method. 


LCS have a range of Corrosion Inhibitors from which we select the one most appropriate for your requirements.  We can provide corrosion inhibitors which have successfully completed the rigorous assessment process required to gain Buildcert approval. 


Legionella Control Solutions Ltd,

Fusion Business Centre,

Magna Way,


S60 1FE

Telephone 01709 717100


Reg Co. No. 8481464

VAT Reg No 162 1284 32.