A long round piece of steel with a hole down the middle. What could be simpler?
It’s not as if pipelines are new technology. Welded steel pipe has been around for decades. Locking bar steel pipe (as used for the Coolgardie water pipeline) was developed over 100 years ago. Wood stave pipe is much older but still used in some places (in fact still made). The Romans are well known for lead pipe. And clay pipes have been found from as far back as 4000 BC.
Pipelines are a very mature technology. But because it’s mature we’ve learned to push the boundaries. What other structure adopts an allowable stress that is 80% of the yield strength? What other metallic structure is buried in the ground and expected to provide decades of service (at that high stress level) with minimal further attention? When you push the boundaries like that you have to have a very clear understanding of what you are doing. That’s one reason we need pipeline engineering.
The other reason is safety. Gas and oil pipelines convey fluids that have potential to cause catastrophe, they do it at extreme pressures (that we become blasé about), and they do it in areas freely accessible to the public.
So our long round piece of steel with a hole becomes deceptively sophisticated. Sophisticated enough that one can spend an entire career in pipeline engineering and still have in-depth expertise in only a part of the field.