The Low-Frequency Building

A building can be heard through a hum or felt through a faint vibration. Fans, pumps and other equipment introduce sources that may become noticeable only when the rest of the room is quiet. Because sound and vibration can travel through air and structure, the place where a disturbance is experienced may be some distance from its origin.

Taking the complaint seriously begins with its pattern. When does it occur? Which equipment is operating? Where is it strongest? These observations make the problem more specific and can help an acoustic or engineering investigation identify the transmission route.

The design response depends on that route. Equipment position, suitable isolation and the relationships between plant and occupied rooms can all become relevant. Addressing them early gives the project more options than a response attempted after rooms are finished and in use.

Low-frequency sound has acquired some dramatic stories, but its architectural importance is practical enough. Occupants should be able to use rooms for their intended activities without persistent mechanical disturbance. A quiet showroom visit will reveal little about a bedroom beside equipment that starts during the night. The useful test includes the building operating under the conditions its occupants will encounter.