NCIDQ IDFX Practice Exam

What is the primary cause of impact noise in a building?

1. Wind passing through gaps

2. Water leaking from pipes

3. Direct contact of objects with surfaces

4. Vibration from machinery

The correct answer is: Direct contact of objects with surfaces

The primary cause of impact noise in a building is indeed related to the direct contact of objects with surfaces. This type of noise results from actions such as footsteps, dropped objects, or furniture being moved across a floor. When an object makes contact with a surface, it produces vibrations that travel through the structure of the building, creating sound waves that can be heard in adjacent spaces. Impact noise is particularly relevant in multi-unit dwellings, where the transmission of sound from one unit to another can significantly affect the comfort and privacy of residents. It is important in the field of interior design and acoustics to understand how to mitigate such noise through the selection of appropriate flooring materials, underlayments, and sound insulation techniques. Other sources of noise, such as air movement from wind, water leaks, or machinery vibrations, create different types of noise, namely airborne or mechanical noise, rather than the impact noise characteristic of physical contact between surfaces and objects.