Quiet flushing
A soundcheck for the new fill valve
The Geberit Type 383 fill valve is one of the quietest valves on the market. In the laboratory in Rapperswil-Jona (CH), acoustics engineer Pietro Allegri demonstrates how precisely sound is measured – and why quietness is no coincidence.
Only three more hits with the rubber hammer on the metal pipe. Then he is satisfied. The last bit of air has escaped from the pipe. The water flows regularly. Pietro Allegri presses the record button. Under his watchful eye, the computer draws a zig-zag line on the screen that depicts the sound of the flowing water. Pietro Allegri is an acoustic engineer at Geberit. His role: he measures the sound caused by Geberit installations in a building and advises planners on individual issues.
Geberit has been carrying out acoustic tests since the mid-1950s, and from 1968 in what was known as the “noise laboratory”. For almost three decades now, Geberit has been operating its own Building Technology and Acoustics Laboratory at headquarters. It enables the construction of extensive, multi-storey installations for acoustic and static tests. Many of these tests are strictly standardised – including the installation test facility where Pietro Allegri measures the noise of the new Geberit Type 383 fill valve.
Measurement in the adjoining room
The installation test facility consists of two rooms, the installation room and the measuring room. In the former, Pietro Allegri installs the fill valve Type 383 in a test cistern. The microphone for the measurement is located in the room behind the installation. “In a real building, this is the bedroom or the apartment next door, for example,” says Pietro Allegri. If the toilet flush is now actuated in the installation room, the fill valve opens and the water rushes through the pipe in the wall. “This noise is exactly what we measure.”
Like its predecessor, the new fill valve Type 383 is clearly among the best in class and thus corresponds to sound class I. “Compared to the previous model, the sound transmission in the room behind the installation has even been reduced by a few decibels,” says Pietro Allegri.
Audible airborne sound cut in half
After the measurement, the engineer turns to the microphone suspended from the ceiling directly above the cistern. Measurements are taken not only in the adjoining room, but also in the installation room itself.
Although there are no standardised requirements for airborne sound from fill valves in the installation room, the measurement gives a good impression of how quiet the new fill valve Type 383 really is. “Compared to the previous model, the perceptible volume has been almost cut in half,” says the acoustics specialist. You can now hardly hear the filling process in the bathroom.
(Header image ©Ben Huggler)
