Don ’ t take a chance on corrosion-Change !
Harvesters Way , EDINBURGH , making the case for a sustainable and environmentally friendly heating system
The implementation of an alternative approach to water treatment and the use of continuous monitoring in the prevention of corrosion in closed systems is not always obvious . The approach used by James Culbertson of the Keenan Consultancy at Harvesters Way explains the operation of such systems , the minimal initial cost and sustainable savings associated with this enhanced process .
Control of corrosion of any closed-circuit heating or cooling system is critical as it imposes a considerable energy load on the system if fouling and debris accumulates . Premature component failure or pipework penetrations can cause catastrophic financial and reputational damage to manufacturers , contractors , designers , and owners alike .
Greater knowledge of the fundamentals of pressurisation and alternative methods to controlling oxygen corrosion can result in substantially lowering of the environmental impact of systems . CIBSE CP1 2020 on Heat Networks has recently recognised the approach of alternative standards such as the German VDI 2035 Part 1 * in this regard .
The introduction of the Northern European guidance leads to better sustainable outcomes based on minimizing oxygen entry and water conditioning such as demineralisation as opposed to the use of chemical inhibition . This approach has been used very successfully in Germany , Switzerland , Austria , the Benelux , Scandinavia etc . for decades . In many parts of the UK the mains water quality is
12 FDPP - www . fdpp . co . uk
Harvesters Way Project - Edinburgh
good enough to fill systems without any further treatment or conditioning .
The key to controlling corrosion in closed systems is to control the level of oxygen entry . The case of Harvesters Way and many others show that correct pressure control , limiting water make up and the use of steel pipework lead to corrosion levels below 5 µ m / y . This is well below the level where damage due to corrosion or corrosion products could occur .
Continuous corrosion monitoring will monitor the system condition and alert the building operator if events occur that will cause an increase in corrosion . Realtime corrosion monitors are low cost and will pay for themselves within 2-4 years thus CAPEX neutral and truly OPEX beneficial .
TRADITIONAL WATER TREATMENT VS WATER CONDITIONING
What is the difference ? Water treatment is adding chemicals to the water to change its properties , in water conditioning the properties of the water are altered by processes such as demineralisation or softening . No chemicals are added .
The traditional UK method of protecting heating systems from corrosion is through the use of chemical inhibitors . Standards such as BS7593:2019 or BSRIA BG29:2021 / BG 50:2013 leave very little option for an alternative approach . The problem is that many people think that because the system has been inhibited it is fully protected regardless of all other parameters . But nothing could be further from the truth . It is the amount of oxygen that enters the system that determines the amount of corrosion that takes place . Even the best inhibitors cannot cope with large amounts of oxygen entering the system .