Class 5 Boiler Practice Exam

Corrosion in boiler water systems is a significant issue that can lead to equipment failure and safety hazards. The correct response highlights that chlorides, sulfates, and oxygen are key contributors to this problem.

Chlorides are especially aggressive because they can penetrate protective oxide layers on metal surfaces, leading to pitting corrosion, which is localized and can cause severe damage even in small areas. Sulfates can contribute to corrosion through the formation of sulfuric acid in presence of water, which can further attack metal surfaces. Additionally, oxygen is highly corrosive when dissolved in water; it can react with metals, leading to oxidation and deterioration.

While calcium and magnesium can affect water hardness and scaling within steam systems, they are not primary agents of corrosion. Pesticides and herbicides generally pertain to environmental concerns rather than corrosion in boiler contexts. Iron and copper, while they can corrode themselves, are not typically the causes of widespread corrosion issues in the system when compared to the more aggressive nature of chlorides, sulfates, and oxygen.