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Flushing Services

Houseman Pre-Commission Chemical Cleaning

Houseman Services recognises the need for modern water systems to have the highest level of cleanliness prior to the commissioning and setting to work of the systems. System contaminants if not removed at the pre-commission cleaning stage, can result in a system over achieving optimum performance. We offer a fully comprehensive pre-commission cleaning service in accordance with the current BSRIA guidelines AG1/2001.

Our programme will usually follow the following methodology:

System Review

A fully trained Houseman operative will attend site prior to our attendance for pre-commission procedures. They will liaise with the site project manager and ensure the adequate provision of flushing points, water to be for flushing procedures and adequate foul sewage drainage points. If required these can be illustrated on the system drawings for installation by mechanical filters. A site specific method statement will then be provided for approval. At this time a water discharge license will be applied for, from the relevant water authority. This is now a legal requirement when dumping large amounts of water with chemical through the foul sewer.

Also, at this time it is prudent to take a sample from the water to be used for the flushing procedure. This sample will be sent for independent analysis and test for TVC & Pseudomonas.

The system is to be fully pressure tested, filled and vented prior to our arrival on site.

Cleaning Process

  1. System dynamic flushing


    The objective is to remove as much debris as possible from the system to reduce the potential for system blockages. This process maximises flow rates through main risers and sub branches as detailed within the BSRIA AG1/2001 guidelines.
  2. Biocide Wash
    If the laboratory analysis indicates high level of bacteria (pseudomonas) within the system, a full biocide  will be carried out to remove bio films and bacteria from the system.
  3. Chemical Clean


    When the system is set to work, movement of the pipe work due to thermal expansion or contraction may cause contaminants to be released into the fluid stream (iron oxide). The objective of chemical cleaning is to loosen surface deposits so they can be removed from the system to create a stable surface larger within the pipe work, which, if maintained by an ongoing water treatment regime, will resist further corrosion.

    On the completion of the chemical clean, the system is then balanced flushed so system parameters are within 10% of incoming mains water.
  4. System Inhibiting
    On completion of the chemical clean, the system will be does with a suitable corrosion inhibitor and biocide to ensure ongoing protection from water to metal corrosion and bacteria based problems. At this stage, samples will be taken and submitted for independent analysis (as detailed within BSRIA AG1/2001).
  5. Back Flushing


    All terminal units should have been isolated during the pre-flushing procedures. The purpose of back-flushing is to remove any small debris that has collected within the terminal units.

On completion of our flushing procedures, a full set of documents will be forwarded for addition to the site O&M manuals. A copy of a typical set of documents can be provided for further information if required.

The Cost of Failure

If this work is not completed to the highest level, it will have a knock on effect to other trades. This can lead to high remedial costs and the delay in practical completion, which could result in financial penalties.

Houseman Water Treatment achieve optimum results by ensuring only OUR framed operatives attend site, resulting in us retaining complete control over the procedures and work practices.

For further information on the services we provide, give us a call on 0845 2720881 or email us via our Contactpage