NCIDQ IDFX EXAM QUESTIONS AND ANSWERS NEW UPDATE 

What is a safety data sheet (SDS)? - answerDocument provided by a manufacturer containing info

about the physical makeup of a substance, proper storage and handling procedures, and other

safety issues.

Define composite wood veneer. - answerProduct made by slicing readily available, fast-growing

trees into veneers, dyeing the veneers, and then gluing them together to create an artificial log.

The log is then re sliced to produce a variety of wood veneers.

Define clerestory. - answerVertically glazed area placed between 2 different roof levels to admit

natural light.

What is the unit of measure for the frequency of sound? - answerThe hertz is the unit of measure

for this and is equal to one cycle per second (Hz)

What is the unit of measure for sound intensity, based on a logarithmic scale? - answerThe decibel

(dB) is the unit of measure for this.

What do most people perceive when a sound increases by 10 dB? - answerWhen a sound increases

by this amount, most people perceive a doubling in loudness.

What frequency range can be heard by most healthy young people? - answerThis range is 20 Hz to

20,000 Hz.

What is the coefficient of absorption? - answerThis is the ratio of the sound intensity absorbed by

a material to the total sound intensity reaching the material.

What is the noise reduction coefficient (NRC)? - answerThis is a single-number average of a

material's coefficients of absorption at 250 Hz, 500 Hz, 1000 Hz, and 2000 Hz, rounded to the

nearest 0.05.

What is reverberation time? - answerThis is the time it takes for the sound level in a space to

decrease 60 dB after the source has stopped producing the sound.

What is the ceiling attenuation class (CAC)? - answerThis is a single-number measure of the

transmission loss through ceiling tiles between two closed rooms where there is no barrier above

the suspended ceiling.