A test that is conducted using National Fire Protection Association 1911 once a year is called a(n) __________ test.

The correct answer is the service/performance test. This type of test is defined by the National Fire Protection Association (NFPA) 1911 as a means to evaluate the operational condition of firefighting apparatus, ensuring that it meets safety and performance standards. Conducting this test annually helps verify that equipment is functioning correctly, which is crucial for reliability during emergency situations.

Service/performance tests typically include checks on components such as the pump, hoses, and other critical systems to ensure they are able to perform as expected under operational conditions. This comprehensive assessment allows fire departments to identify any potential issues and address them proactively, thus enhancing overall safety and effectiveness.

In contrast, an inspection test refers to a review of equipment without necessarily conducting a performance evaluation, while a pump efficiency test specifically measures how well a pump operates under controlled conditions. A flow test focuses on measuring the output of water from a nozzle or hydrant, not necessarily reflecting the apparatus's overall performance. Although these tests are important, they do not encompass the broader scope and intent of the annual service/performance test as defined by NFPA 1911.