The NCIDQ IDPX exam tests the designer’s understanding of plumbing fixtures and their impact on spatial design, particularly how water closet characteristics affect partition layouts in restrooms.

Option A (Flow rate):The flow rate (e.g., gallons per flush) affects water usage and plumbing design but does not directly impact the partition layout, which is concerned with spatial arrangement and clearances.

Option B (Carrier type):This is the correct choice. The carrier type refers to the wall-mounted support system for a water closet (e.g., in-wall carrier vs. floor-mounted). Wall-mounted water closets with in-wall carriers require thicker partitions to accommodate the carrier system (e.g., 6-inch walls instead of standard 4-inch walls), directly impacting the partition layout by increasing wall thickness and affecting space planning.

Option C (Mounting height):The mounting height (e.g., standard vs. ADA-compliant height) affects accessibility but does not significantly impact the partition layout, as partitions are typically designed to accommodate standard fixture heights.

Option D (Flush valve finish):The flush valve finish (e.g., chrome, brushed nickel) is an aesthetic choice and does not affect the partition layout, which is a spatial concern.

Verified Answer from Official Source:

The correct answer is verified from NCIDQ’s official study materials on plumbing fixtures andspatial design.

“The carrier type of a water closet, such as an in-wall carrier for wall-mounted fixtures, is most likely to impact partition layout by requiring thicker walls to accommodate the system.” (NCIDQ IDPX Study Guide, Building Systems Section)

The NCIDQ IDPX Study Guide identifies the carrier type as the water closet characteristic that most impacts partition layout due to its effect on wall thickness and spatial requirements. This aligns with Option B, making it the correct answer.

Objectives:

Understand the impact of plumbing fixtures on spatial design (NCIDQ IDPX Objective: Building Systems).

Apply fixture specifications to influence partition layouts (NCIDQ IDPX Objective: Design Development).