As a nation, we have relied on chemical dosing as a trusted method to maintain closed loop systems for decades now, but chemical inhibitors are not without monetary, compliance, and environmental cost. For a start, they aren’t free, they also come under Control of Substances Hazardous to Health (COSHH) regulations, so require careful management. In addition, they are not environmentally friendly things, ‘biocide’ quite literally means ‘a substance that destroys living things’!
Hence why there is a growing interest in chemical free methods of water treatment for chilled and heating water systems. Guidance such as VDI 2035 ‘Prevention of damage in water heating installations’ from Germany, has demonstrated that with good design, chemicals need not be relied on for corrosion prevention. This standard promotes maintaining closed water system quality through carefully controlled make-up water parameters, to combat the root causes of poor water quality, at the point of entry to a closed loop.
VDI 2035 emphasises a few key elements:
- Proper system flushing prior to commissioning;
- Airtight system design;
- Effective deaeration;
- Dirt and metal separation; and
- Minimal water consumption.
In short, a clean, sealed, low oxygen system shouldn’t require continuous chemical inhibitors.
The benefits of a chemical free system are compelling;
- Reduced COSHH requirements
- Lower environmental impact
- Better heat transfer; and
- Reduced reliance on manual dosing.
However, unfortunately it is not quite as simple just stopping your chemical deliveries and hoping for the best. Converting an existing closed water system to be chemical free can be an extensive process and may not be a viable option depending on your current system design.
Thorough system surveys, pipework cleaning and remedial flushing are normally essential steps to bring the system into a clean state prior to transition. Older systems with existing corrosion damage are often unsuitable to move to chemical free water treatment, without upgrading part or all the system first.
When properly designed and assessed, chemical-free water treatment offers a forward thinking and more sustainable alternative to chemical corrosion control. It is best placed in a new-build that has been specifically designed to run chemical-free.