Why do these pipes seem to go out of their way to go around the moon? Actually, this is an expansion loop, provided so that the pipes and the things to which they are connected don't become damaged as they expand and contract with temperature. On the evenings I was here, in the silence of the night, every so often a creak or snap could be heard echoing throughout the plant. It sounded like it was coming from every direction at once. It probably was, nearly every building in this facility is connected together with miles of pipe.