What is an example of limits for the control measure of keeping cooling tower basins free of built-up materials?

The correct example of limits for the control measure of keeping cooling tower basins free of built-up materials is that the buildup in the basin must not exceed 1/2 inch in depth. This specific limit is in alignment with best practices aimed at preventing the accumulation of organic materials, sediments, and impurities that could promote the growth of Legionella bacteria.

Maintaining a maximum buildup of this depth helps ensure that water circulation remains efficient and reduces the risk of potential hazards, including water stagnation and nutrient sources for bacteria. Regular monitoring and management of these levels are essential to minimize any chance of outbreaks linked to cooling towers.

In contrast, allowing greater buildup or eliminating it completely without a specific depth guideline could lead to either a disregard for effective monitoring or impractical maintenance strategies. This context reinforces why setting a clear limit—like the 1/2 inch—provides a balanced approach to maintaining cooling tower safety and operational effectiveness.