This paper presents the first part of a two-paper series on transient tests for checking the Trieste subsea pipeline, aiming to develop field test procedures for fault detection. Subsea pipelines are critical for transporting oil, gas, and water but are vulnerable to damage from both human-made and natural causes. They are difficult to access, requiring reliable and cost-effective inspection and monitoring technologies. Transient-test-based techniques (TTBTs) are proposed as a solution, involving the generation of pressure waves to detect anomalies. The paper focuses on selecting the appropriate maneuver to generate pressure waves and planning the steps for effective fault detection. It also reviews existing fault detection technologies and evaluates the performance of the proposed procedure in terms of pressure regime stability before testing. The Trieste subsea pipeline, which runs under the coastal road to Trieste, is characterized by a long length, large diameter, and absence of branches, making it suitable for testing TTBTs. The paper describes the pipeline's layout, the use of a special device to generate pressure waves, and the field procedure for transient tests. The procedure involves a series of steps, including pressure monitoring, valve operations, and pressure wave generation. The results of the preliminary survey and the effects of timing on pressure wave propagation are discussed, highlighting the importance of precise timing to ensure accurate fault detection. The paper concludes that TTBTs offer a promising approach for subsea pipeline inspection, with the potential for application in similar large-scale systems. The companion paper will present the results of the fault detection procedure.This paper presents the first part of a two-paper series on transient tests for checking the Trieste subsea pipeline, aiming to develop field test procedures for fault detection. Subsea pipelines are critical for transporting oil, gas, and water but are vulnerable to damage from both human-made and natural causes. They are difficult to access, requiring reliable and cost-effective inspection and monitoring technologies. Transient-test-based techniques (TTBTs) are proposed as a solution, involving the generation of pressure waves to detect anomalies. The paper focuses on selecting the appropriate maneuver to generate pressure waves and planning the steps for effective fault detection. It also reviews existing fault detection technologies and evaluates the performance of the proposed procedure in terms of pressure regime stability before testing. The Trieste subsea pipeline, which runs under the coastal road to Trieste, is characterized by a long length, large diameter, and absence of branches, making it suitable for testing TTBTs. The paper describes the pipeline's layout, the use of a special device to generate pressure waves, and the field procedure for transient tests. The procedure involves a series of steps, including pressure monitoring, valve operations, and pressure wave generation. The results of the preliminary survey and the effects of timing on pressure wave propagation are discussed, highlighting the importance of precise timing to ensure accurate fault detection. The paper concludes that TTBTs offer a promising approach for subsea pipeline inspection, with the potential for application in similar large-scale systems. The companion paper will present the results of the fault detection procedure.