New York Low Pressure Boiler COF Practice

What is used between two different types of metallic pipes when connecting them?

1. A dielectric kit or fitting

2. A solder joint

3. A metal coupling

4. A rubber gasket

The correct answer is: A dielectric kit or fitting

When connecting two different types of metallic pipes, a dielectric kit or fitting is essential to prevent galvanic corrosion, which can occur when two dissimilar metals come into contact with each other in the presence of an electrolyte, such as water. This corrosion can lead to significant deterioration of the pipes over time. A dielectric fitting works by providing an insulating barrier between the two metals, allowing them to connect without the risk of electrical conductivity that can lead to corrosion problems. It typically consists of a non-conductive material that separates the two metal parts, ensuring that they do not directly contact each other. Using a solder joint would not be appropriate in this situation as it requires both pipes to be of a similar material that can be soldered, which is not the case for dissimilar metals. A metal coupling would create a direct connection between the two pipes, thus increasing the risk of corrosion. A rubber gasket, while useful in sealing connections and preventing leaks, does not provide the necessary electrical insulation to protect against galvanic corrosion.