Leading pipe manufacturer, Geberit, is urging installers and specifiers to realise the benefits of carbon steel pipework; a cost effective product that is corrosion resistant in closed-circuit systems. A recent re-visit to Mater Hospital in Ireland, where Geberit Mapress carbon steel had been installed some 12 years ago, revealed corrosion free pipework, as effective as the day it was commissioned.
Copper has long been used thanks to its exceptional corrosion resistant properties, however its cost is much greater and more volatile than carbon steel. If installed correctly, in closed-circuit systems, carbon steel is equally resistant to degradation and offers significant savings when compared with copper. Crucially, the price of carbon steel is much more stable, allowing specifiers to accurately plan a projects expense well in advance.
Simon Spridgeon, Product and Technical Manager for Geberit, explains why correct procedure is imperative when it comes to realising the benefits of carbon steel. Problems can occur if carbon steel is not installed and commissioned correctly. Pipes should be protected against moisture and the influence of weather. For chilled water applications, a vapour barrier must always be maintained in areas where condensation is likely to occur. If the carbon steel pipe is coated in plastic, as at Mater Hospital, extra protection is not required (although the fittings and pipe ends still need full protection.)
The probability of corrosion is further increased if oxygen is present in the circuit concentrations in excess of 0.1g/m3 indicate a greater chance of corrosion. This could occur through compression glands, screw connections or automatic air vent valves if there is negative pressure in the heating system. However, there is no risk of corrosive damage from oxygen that enters when filling and supplementing with water since the amount of oxygen is very low. Mater Hospital is an excellent example of good practice; as a consequence, the buildings carbon steel pipework will remain corrosion free for many years to come.
For a low cost alternative to copper, carbon steel is a great option. To keep up to its corrosion resistant claims, however, correct procedure must be adhered to worth doing considering its benefits to a projects overheads.