Which of the following is the correct order to locate a HIGH-PRESSURE STEEL MAIN?

Locating a high-pressure steel main requires understanding the components and their relationship within the system. The correct order is Service Riser, then ETC (Emergency Termination Connection) or ETS (Emergency Termination System), followed by the Valve.

The Service Riser is crucial because it is the vertical section that connects the pipeline to the surface and is usually where the high-pressure main begins when transitioning to services. Following the riser, accessing the ETC/ETS is essential as it provides emergency connection points that facilitate safe and effective control of gas flows during maintenance or emergencies. Finally, the valve is the last element in this order because it typically operates after the service connection has been secured through the riser and ETC/ETS, allowing for necessary adjustments to the flow and pressure of the gas being delivered.

Understanding the purpose and position of each component in the order is critical to ensuring safety and functionality when locating and working with high-pressure steel mains, which emphasizes why this sequence is accurate.