Factorio Forums

Normally, the player cannot walk through above ground pipes. This extends to when a storage tank is connected directly to a steam engine:
My expectation than is that this would extend to all cases where two buildings are directly adjacent with a pipe connection.

However, what actually happens is that when a chemical plant is directly adjacent to a storage tank and connected with a fluid connection, the player can walk right through it:

That is not a bug.

Can you elaborate? Have the developers said this is intentional? And if so, why?

If the gap between the collision boxes allows the player the pass through, then it is not a bug. The boxes will not be changed because you would create an avalanche of of pass/not pass situations with other entities.

Not a bug.
Pipe connections themselves are not a concept that can collide with characters and so because character does not collide with anything, character is allowed to pass through there. Assembler and storage tank wont change their collision mask as Pipes do because a single fluid connection would adjust collision box on the entire side (relevant for both), and because expanding collision boxes creates a lot of problems (73458 with machines with electric energy source where by changing collision box, an entity was going in or out of electric network range).

Got it. Thanks for the explanation!