I know nothing about pipeline technology; maybe someone can answer this. Is there an automatic shutdown system for pipelines (triggered by a sudden loss of pressure), or do crews have to shut valves on both sides of the damage?
Most major pipelines have automated shutdown valves.
But when pipelines are hundreds of miles long, the valve stations are often 10 to 25 miles apart. A rupture between those still have a lot of volume to lose.
Also, pipeline pressures normally vary with pumping conditions. The sensing of the rupture is more difficult than most would imagine. Sensors 10 miles from the rupture don’t see an immediate change. Typically you trigger the shutdown valves not on a low pressure but on a very fast dropping pressure rate.
Also, these valves at remote locations are rarely operated. Some do partial stroke tests. But to do a complete valve operation test you have to shutdown the pipeline.