Piping and air-conditioning units gradually lose their durability and performance due to deterioration caused by corrosion. Eventually, such deterioration may reach the point where it causes a water leak or machinery malfunction. Often this arises under a combination of “Materials” and “Environment”, so it is important to grasp the characteristics of material corrosion from certain environments (water quality, temperature, flow rate, etc.).

In order to master these topics, we have been studying corrosion for more than fifteen years. This is very unusual amongst Japanese construction companies. We strive hard to ensure the longevity of our air conditioning systems for our customers by putting into practice the results of these current studies.

We promptly respond to deterioration diagnoses using the following analysis instruments: industrial videoscopes, ultrasonic thickness gauges, pH meters, dissolved oxygen meters, X-ray fluorescence spectrometers, etc.

In our deterioration diagnosis, we evaluate the extent of any deterioration more accurately by understanding the electrochemical characteristics, by means of extreme value analysis.

IIndustrial Videoscopes (OLYMPUS INDUSTRIAL- iPLEX SA)

X-ray Fluorescence Spectrometer (JEOL -JSX-3202 ELEMENT ANALYZER)   Water Quality Anlysers (pH Meter, Dissolved Oxygen Meter,etc.)   Potentiostat / Galvanostat (Toho Technical Reserach-8-Channel Potentiostat / Galvanostat Model PS08)

				Galvanic Corrosion that occurs in water supply line (lining steel pipe) used for 11 years. The joint with the valve made of the gunmetal corrodes selectively.
				Erosion-Corrosion that occurs in copper piping for supplying hot water used for five years. Deterioration in piping was promoted by the overflow velocity and the water quality.
				Intergranular Corrosion that occurs in weld of stainless steel pipe (SUS304) for supplying hot water. It leaked from the use beginning within one year. It is seen well in stainless steels made sensitization by the welding heat influence.
				Pitting Corrosion that occurs in heat exchanger (copper coil) of air handling unit that used it for 11 years . Various factors like the water quality and the manufacturing process etc. of the material are generated more than once.
				Dezincification that occurs in drain trap of washing stand of rest room used for seven years (made of brass). Water that contains a lot of free carbonic acid is expected to have accelerated the progress of corrosion.

In galvanized steel pipes, zinc is used as a sacrificial anode for cathodic protection of the steel. However, problems resulting from corrosion due to reversed potential in galvanized steel pipes are often reported. Such reversed potential between zinc and steel has been extensively studied for more than 60 years, but the reason behind it has yet to be understood. In order to clarify this phenomenon, and to reduce the number of problems arising from corrosion of galvanized pipes, we have been advancing our research.