NCIDQ IDFX questions with correct answers

The principal consideration in acoustic control in large spaces is the sound absorptive quality of the ________. Answer Ceiling [Noise reduction within a space: In larger rooms, ceiling treatment is most effective, while in smaller rooms, wall treatment is more effective.] These are part of the HVAC system used for return air and generally have no movable parts or slats for adjustment. Answer Vents [Source: Qpractice NCIDQ Exam Guide, Structural, Mechanical and Plumbing Systems -Diffusers have direction fins at different angles (sometimes adjustable) to distribute the air throughout the space. -Registers (in the floor or wall) can be open, closed, or adjusted somewhere in-between. -Grilles often used for return air have no movable parts or slats for adjustment.] In a new lifestyle hotel, the spa suites will have 4 poster canopy beds. How far away from the sprinkler heads should the beds and panels be? Answer 20 inches [The canopy would be considered an obstruction to discharge as defined in NFPA 13, 8.5.5 Obstructions to Sprinkler Discharge, which restricts continuous or noncontinuous obstructions less than or equal to 18in (450mm) below the sprinkler deflector.] What are the variables of noise reduction between two rooms? Answer The three most important variables are the wall's stiffness, the transmission loss, and the common area between rooms.