The BSRIA BG29 document was first launched as AG 8/91 Pre-commissioning Cleaning of Water Systems in 1991, almost 30 years ago. Many changes have happened in heating and cooling systems since then as we seek to achieve far greater energy efficiencies, resulting in significant differences in how these systems are now installed and operated. Other changes including an increased emphasis on microbiological control and innovations in cleaning techniques. The new sixth edition of BSRIA BG29 reflects these changes.
The main differences/additions to the new BSRIA BG29 2020 compared to the BSRIA BG29 2012 document are summarised below. Further blogs will focus on these topics in more detail to explore their potential impact on this sector of the UK water treatment market.
Cleaning precautions for thin-walled carbon steel pipes
There has undoubtedly been an increase in the use of thin-walled carbon steel pipework for new installations of closed water heating and cooling systems in the UK. Although a cost-effective, easy to install system, there is little margin for error in every stage of the life of the pipework. Alternative methods for cleaning this type of pipework are included in the new guide.
Closed loop pre-treatment cleaning CPC procedures
This method for filling and cleaning systems ensures that systems are filled with inhibitor and biocide from first fill and that the system is recirculated and cleaned through a combined process of velocity and filtration. The procedure is therefore quicker and results in a much less aggressive clean of pipework than traditional methods, also ensuring that no water or minimal water is discharged to drain.
Pre-treatment options described in German directive VDI 2035
The new BSRIA BG20 2020 gives an overview of VDI 2035, whereby all water used in the closed system must be demineralised, deaerated and controlled. In VDI 2035, chemical treatment of closed systems is used purely as a last resort in response to oxygen ingress and ensuing corrosion. A small number of other European countries including Austria and Germany also have guidelines similar to VDI 2035 which differ markedly from the traditional BSRIA BG29 approach.
Corrosion monitoring solutions
Although the monitoring of closed systems by sampling according to BS8552 is still recommended, on-line monitoring solutions are also described in the guide. Remote monitoring can be used to measure: dissolved oxygen, conductivity as an indicator of cleaner or inhibitor concentration, pH, water makeup volumes, system pressure, flow rates and metallic corrosion rates.
The guide includes increased content on heat networks and low carbon systems.
Microbiological specifications on sampling have been reviewed and a 5 day turn around SRB testing procedure is now included.
BSRIA BG29/2020 is not designed for use in:
- occupied buildings with difficult access
- systems in regular operation for a period of more than three months since completion of the cleaning process or domestic systems.
As previously, the guide should not be taken as not part of a contractual obligation but as good practice guidelines for the cleaning of pipework systems.
**Parts of this blog post are reproduced from BSRIA BG29/2020 Pre-commission Cleaning of Pipework Systems 6th edition.