How many degrees of increase in hanging dry bulb would necessitate a follow-on survey?

The choice of 5 degrees as the threshold for necessitating a follow-on survey is correct because it is a standard measurement criterion within the context of evaluating environmental conditions in gas turbine systems. An increase in the hanging dry bulb temperature by 5 degrees indicates a significant change in the ambient conditions that can affect the performance of the gas turbine.

In operational contexts, maintaining optimal temperature levels is crucial for the efficiency and reliability of gas turbines. An increase of this magnitude can suggest potential issues such as changes in ventilation, cooling efficiency, or external environmental factors that could impact the system's performance. Therefore, a follow-on survey would be warranted to investigate the cause of this temperature increase, assess any potential risks, and implement appropriate remedial measures.

Monitoring changes in hanging dry bulb temperatures is an essential part of effective gas turbine management, as it helps ensure that all systems are functioning within their designed parameters, contributing to safe operations and equipment longevity.