Corrosion is the invisible enemy of water systems and its consequences are costly in both time and money. Building owners tend to rely on sporadic sampling tests or only react once a system has failed. It’s time to look at advancements in technology and implement methods of prevention, rather than cure, to avoid the expense and inconvenience of corrosion.
Heating technology is advancing all the time. Pumps and boilers are becoming smaller and more efficient. New materials are introduced and applied to components such as pipework and fittings, as well as heat exchangers and valves.
These advances make systems more energy efficient and allow more space for offices or living accommodation. Yet, no progress comes without downsides or the need to adapt… Are such systems as reliable as they used to be, do they last as long, and do they need more or less maintenance?
The hidden costs of progress
Progress means that systems and their components are becoming increasingly more complex, yet skills levels in the industry are dropping. As a result, systems often don’t operate anywhere near their designed efficiency. They suffer frequent breakdowns and, like modern cars, can only be fixed by experts.
Modern heating and cooling systems need high-quality, clean water to transfer energy efficiently. Even small amounts of dirt or sludge can cause costly breakdowns. It is then no coincidence that dirt separators of all kinds are now prolific. Whether fine mesh or bag filters, in line, side stream or with magnets, they are all designed to do one thing – keep the water clean.
Early warning system
Insurance companies have seen a massive increase in claims for water loss, as have boiler and pump manufacturers for warranty claims. The majority of these issues can be traced back to corrosion problems – but often not recognised as the cause for system problems, leading to people fighting the visible symptoms and not the cause. Even if it is recognised to be corrosion, the response is all too often a chemical one, which fails to tackle the underlying cause.
By the time the problems have become visible, through failing components or blockages, costs will be spiralling. Corrosion coupons or water analysis are traditional methods of testing for corrosion, but these only give an indication as to what the current state of the water is.
Wouldn’t it make sense, therefore, to have an online system that continuously measures corrosion rates, without the need for coupons or samples?
Until recently, equipment to measure corrosion, such as the LPR method, has been prohibitively expensive for HVAC systems. Indirect measurements, such as pH or conductivity, have been possible, but require specific expertise to evaluate the results.
Fortunately, like heating technology, sensor technology has rapidly advanced and a number of affordable direct and indirect measurement corrosion monitoring systems are now available. The indirect systems measure water quality parameters such as pH and conductivity, whereas the direct monitors measure corrosion directly, using a single sensor, and are therefore much more cost effective.
One sensor solution
The patented Risycor uses an electronic version of the proven coupon method. The advantage of this direct method is that only one type of sensor is required.
A major advantage of monitoring systems is that they don’t just measure, but also record, corrosion levels during the lifetime of the plant. Most of these systems can also send an alarm when corrosion rates exceed safe levels, or even have remote viewing functions.
These alarms give operators and FM companies plenty of time to check, locate and remedy the causes of the increased corrosion levels before they do any costly damage to the system. This goes even for systems with thin wall carbon steel pipework for which corrosion monitoring is a must… “for routine maintenance and correcting simpler problems a smart system could definitely have its advantages”, comments Chris Thompson, research engineer, BSRIA.
Antony Corbett, Geberit incorporating Twyford, adds: “Ongoing water monitoring in carbon steel systems should be included as part of any specification and design. Modern water monitoring devices offer greater visibility of the system with early warning detection of potential issues, especially corrosion – all with greater flexibility and lower costs than before.”