Plumbing

Roles: pipe, fitting, joint, valve, pressure, flow, drain, seal, reservoir, plumber

The craft of installing and maintaining systems that convey fluids through enclosed channels. As a source domain, plumbing foregrounds hidden infrastructure that is noticed only when it fails, the difference between flow and blockage, the importance of joints and seals at connection points, and the consequences of pressure in closed systems. Its metaphorical power comes from the invisibility principle: good plumbing disappears, and the work is appreciated only in its absence.

As Source Frame (1)