The problem
The courtyard is the view from 46 inpatient rooms, some of them occupied by people who will be in them for a year. The hospital wanted something alive to look at. The clinical team wanted the background level at the nearest openable window below 40 dB(A). An ordinary 2 m aerated jet measures 61 dB(A) at 3 m. Almost everything that looks lively is loud, because what makes water loud is air being dragged into it.
What we did
We used effects that carry no entrained air. Eighteen laminar jets — glass rods with a settling chamber and honeycomb straightener, silent in flight — arranged in an arc, each landing in a cast bronze bowl. The bowls fill over 40 to 70 seconds, tip on a bearing when the moment overcomes the counterweight, drain, and swing back. The courtyard is never still and never repeats, because the bowls are hand-cast and no two fill in the same time.
The tipping event is the only noise, and it is a single soft pour into 300 mm of water rather than a continuous splash. Commissioned measurement at the nearest window: 36 dB(A), with the tip events peaking at 41 dB(A) for under two seconds. The clinical team signed it off after listening from a ward bed at 3 a.m., which is the only test that counted.
Maintenance
Laminar jets are intolerant of dirt — a single leaf fragment in the straightener turns a glass rod into a spray, and it is immediately obvious. The courtyard is planted with species that hold their leaves, the strainer is duplex so it can be cleaned without stopping, and the bowls come off their bearings by hand for descaling. Seoul water is soft enough that this is a twice-yearly job.
