__________ is performed on new systems to test flow rates and on existing systems to ensure that the system is still performing well.

The correct answer is hydrant testing, which is crucial in the assessment of fire protection systems. This process involves measuring the flow rates and pressure available from fire hydrants to ensure they meet the requirements needed for effective firefighting operations. In new systems, hydrant testing confirms that the infrastructure can deliver adequate water supply in emergency situations. When applied to existing systems, it verifies that the hydrants are still functioning properly and can provide the necessary flow rates for current fire protection needs.

Hydrant testing is vital for both municipal and private fire suppression systems, as it helps identify any potential issues that may arise due to changes in water supply, system deterioration, or other factors affecting performance. Regular testing ensures compliance with safety standards and allows fire departments to strategize their response tactics effectively based on the data collected.

Other options are related to various assessments and tests within the fire protection field. However, hydrant testing specifically addresses both flow rates in new installations and ongoing performance evaluations in existing systems, making it the most appropriate choice for this question.