Add a little Copper Corrosion Inhibitor (generally Tolytriazole although BZT is becoming more popular since it is more halogen stable) to every drum of Steel Corrosion Inhibitor product, and you should be all set.

"Most customers would rather replace 100 feet of mild steel than one inch of copper." This is because that one inch is going to be in the middle of your chiller. This has been our attitude for at least the last 5 years.

With the introduction of Internally Enhanced Condenser Tubes and some pitting beginning in the first year with some failing in as little as 2 ½ years, and we have a major problem.

However, it is not just the Enhanced Tubes, it’s the smooth Tubes that are also failing prematurely at many sites across the country.

Many of our Commercial Accounts have large convoluted systems. Many of the designs allow for long runs; low flow or no flow areas; and many have hundreds of package units aside from the large central plant.

To make the situation even worse, these same sites with the hundreds of package units, are replacing the steel low flow runs with copper.

Most water treatment programs are designed for the ideal system. This means 3-5 feet per second flows; a big central plant; large diameter steel piping; and a short run from the tower to the condenser. The only copper you should have is the condenser itself and a few brass valves.

In order to determine if there is enough copper corrosion inhibitor in a system, you must first run a copper test. You multiply the copper residual by two to find out the demand of the water for copper corrosion inhibitor. You then run a Copper Corrosion Inhibitor test and subtract the demand. If the result is positive, you have protection.

The response of the Water Treatment Suppliers on the testing of Copper Corrosion Inhibitor is as follows:

1. There is enough Tolytriazole in the drum. The drum is properly   formulated so that there is a relationship between the Steel Corrosion Inhibitor and the Copper Corrosion Inhibitor. If there is enough of one, you have enough of the other.
2. The Copper Corrosion Coupons always look great.
    
3. The test takes too much time.
    
4. I don’t have the field equipment.
    
5. The Toly test is not accurate.

Well, the situation is that Toly is absorbed by the system at a different rate than the steel corrosion inhibitor; halogens and UV degrade the Toly; the chemistry at the hotter condenser tube is different than the chemistry in the cooler bulk water; and the field test for Toly is accurate enough.

We continue to do research on the Copper Issue. One of the current studies we are conducting at a major Ivy League University, is showing that it’s not the field Toly test which is the issue. It’s the copper test. You need a total copper reading in order to mass balance and this requires complete digestion. The digestions are not being done.

We monitor our customers on a Quarterly basis in order to find the seasonal fluctuations in the systems. Our copper test is done via ICP with a flame temperature of 7,000 degrees C.

Some customers are now having us sample, or are sending in samples on a monthly basis to insure proper copper protection.