Reducing water wastage in pre-commissioning cleaning

12th October 2017

Pre-commissioning cleaning is an essential element of new water system hand over, but, with this process accounting for half of all water usage when a building is constructed, while essential, it is not always that sustainable. There are ways to reduce water wastage, however, and improve the overall condition of your water systems throughout their life.

What is pre-commissioning cleaning?

Pre-commissioning cleaning is a standard requirement of all new closed water installations under the latest BSRIA guidelines. An essential process, it ensures a water system starts life in a clean and efficient state, preventing issues such as corrosion further down the line – as long as appropriate maintenance is employed. Cutting corners during this process is a false economy, as if not carried out effectively, repairs and breakdown will cost more in the long-run.

Water wastage occurs when large volumes of water are used to flush the system, removing debris and maximising flow rates. Following flushing, biocide washing and chemical cleaning is used to remove bio-films and surface deposits, creating a stable surface more likely to withstand corrosion, backed-up by a corrosion inhibitor to further prevent damage. Finally, there’s back flushing, with yet more water used to remove any last remnants of debris.

How can water wastage be reduced?

By flushing and cleaning water systems using the Hydrosphere process, which uses advanced filtration methods, the volume of water required can be greatly reduced, while still ensuring that debris is removed. This approach also cuts cleaning times, saving water and reducing time on the job when compared with traditional methods. Monitoring is also key during this process, with a real-time indication of microbiological activity allowing for prompt and preemptive treatment adjustments.

Beyond pre-commissioning cleaning

Correct water system construction and pre-commissioning cleaning are essential for preventing on-going issues, in particular, corrosion. Systems must be pressurised properly throughout the 24/7 cycle and expansion capacity needs to be specified correctly, alongside system pressures. Once the right foundations have been laid, these parameters must be maintained over the system’s lifetime.

If system pressures exceed this baseline, water losses may occur, requiring fresh, aerated water to top up the system. If pressures get too low, air could be sucked into the system. To prevent this from happening, monitoring should not only be employed during pre-commissioning cleaning, but throughout a system’s life. We use the Hevasure system, which provides 24/7 real time data, to ensure end users have a proper understanding of water system conditions.

By having a continuous handle on water conditions, as soon as potentially corrosive conditions are flagged up, steps can be taken immediately to stop corrosion in its tracks. This is particularly true of oxygen ingress. While chemical inhibitors can help, they should be considered a secondary line of defence, not a substitution for resolving oxygenation problems.

Bacterial levels can also influence corrosion, in particular the build-up of sulphite-reducing bacteria (SRB). Water system monitoring should therefore not only check for oxygen, but the presence of these organisms.

Exceeding the BSRIA guidelines

BSRIA guidelines focus on regular water sampling to judge the condition of the system, and the treatment. While this has merit, and should be adhered to, we believe that on-going monitoring is the only sure-fire way to prevent corrosion and hygiene issues.

New, innovative water monitoring systems, such as Hevasure, take constant, real-time readings, allowing for issues to be identified and addressed immediately before costly problems take hold. When installed during construction and the pre-commissioning and fit-out periods, this type of monitoring instantly notifies conditions that may cause corrosion, as well as unplanned water losses.

For more information about our pre-commissioning cleaning services, click here.