What principle does the PHEL curve provide information about?

The PHEL curve, which stands for Personnel Hazard Exposure Limits, provides critical information regarding exposure limits for personnel safety. This curve is used to define the acceptable levels of various hazards in a work environment, ensuring that personnel are not exposed to conditions that could adversely affect their health or safety.

In the context of gas turbine systems, maintaining personnel safety is paramount, especially considering the potential risks associated with working in and around high-temperature environments and the operational aspects of turbines. By adhering to the guidelines set forth by the PHEL curve, organizations can effectively manage exposure levels, thereby reducing the risk of injury or illness among workers.

The other choices do not accurately represent the function of the PHEL curve. Fuel efficiency metrics relate specifically to how effectively a gas turbine converts fuel into energy, which is not covered by the PHEL curve. Temperature variation effects might pertain to performance parameters of the gas turbine but are unrelated to personnel exposure limits. Equipment lifespan assessment focuses on the durability and operational life of the machinery itself, rather than the safety limits concerning human interaction.