The NCIDQ IDPX exam tests the designer’s understanding of acoustical design, specifically how to mitigate impact noise, which is caused by physical contact (e.g., high heels on a hard floor) and transmitted through the structure. Impact noise is best addressed by isolating the vibration at the source, rather than relying solely on sound absorption.
Option A (Higher NRC in the ceiling material):NRC (Noise Reduction Coefficient) measures a material’s ability to absorb airborne sound within a space. While a higher NRC ceiling material can reduce reverberation, it does not effectively mitigate impact noise, which is transmitted through the floor structure to the space below.
Option B (Framed-in upholstered wall panel system):Upholstered wall panels also absorb airborne sound but have minimal effect on impact noise, as they do not address the vibration at the floor level where the noise originates.
Option C (Resilient underlayment in the floor assembly):This is the most effective method. Resilient underlayment (e.g., rubber or cork) is a layer installed beneath the hard floor surface that absorbs and isolates vibrations caused by impact, such as footsteps from high heels. This reduces the transmission of impact noise to the structure and the space below, making it the best solution.
Option D (Blanket insulation between joists and trusses):Blanket insulation (e.g., fiberglass batt) between joists helps reduce airborne sound transmission but has little effect on impact noise, as it does not isolate the vibration at the floor surface.
Verified Answer from Official Source:
The correct answer is verified from NCIDQ’s official study materials on acoustical design and noise control.
“To mitigate impact noise from hard floor surfaces, a resilient underlayment should be incorporated into the floor assembly to absorb vibrations and reduce transmission to the structure below.” (NCIDQ IDPX Study Guide, Acoustical Design Section)
The NCIDQ IDPX Study Guide specifies that resilient underlayment is the most effective method for mitigating impact noise, as it directly addresses the source of the vibration. This aligns with Option C, making it the best construction method for reducing noise from high heels on a hard floor.
Objectives:
Understand methods for controlling impact noise in interior spaces (NCIDQ IDPX Objective: Acoustical Design).
Apply construction detailing to achieve acoustical performance (NCIDQ IDPX Objective: Detailing and Construction).
[References:, NCIDQ IDPX Study Guide, Acoustical Design Section., National Council for Interior Design Qualification (NCIDQ), IDPX Exam Blueprint, Section on Building Systems., ]
