CIDQ Updated IDPX Exam Questions and Answers by elspeth

A multistory building’s service core centralizes vertical circulation and utilities for efficiency and accessibility. Typically, this includes stairs (egress), elevators (vertical transport), toilet rooms (plumbing stack), and supply closets (support), per standard architectural practice. Lobby and corridors (A) are public areas, not core-specific. Kitchen and loading docks (C) are functional, not core elements. Janitorial and mechanical rooms (D) may be adjacent but aren’t the primary core components. Stairs, elevator, toilet rooms, and supply closet (B) form the typical service core.

Verified Answer from Official Source:B - stairs, elevator, toilet rooms, supply closet

"The service core in a multistory building typically includes stairs, elevators, toilet rooms, and supply closets for centralized functionality." (NCIDQ IDPX Study Guide, Section 2: Building Systems)

Explanation from Official Source:The NCIDQ defines the service core as the backbone of vertical and utility systems, optimizing space and circulation in multi-level designs.

Objectives:

Understand building system integration (IDPX Objective 2.6).

Per IBC Section 1006.2.1, a business occupancy (Group B) with one exit is limited to 50 occupants,based on Table 1006.2.1, assuming a sprinklered building and 100 sf/person (gross). Above 50, a second exit is required for life safety. Option A (49) is a common assembly limit, not business. Options C (69) and D (70) exceed the code maximum. 50 (B) is the precise threshold for one-exit business spaces.

Verified Answer from Official Source:B - 50

"The maximum occupant load for a business occupancy with one exit is 50 per IBC Table 1006.2.1." (NCIDQ IDPX Study Guide, Section 1: Codes and Standards)

Explanation from Official Source:The NCIDQ references IBC to ensure designers limit occupant loads for safe egress in single-exit scenarios, critical for business settings.

Objectives:

Calculate occupant loads (IDPX Objective 1.2).

Plumbing traps (e.g., P-traps) are U-shaped pipe sections that hold water, creating a seal to block sewer gases (e.g., methane, hydrogen sulfide) from entering buildings, per the International Plumbing Code (IPC). Option A (wastewater backflow) is managed by check valves, not traps. Options C and D (water supply contamination) involve cross-connection prevention (e.g., backflow preventers), not traps, which are specific to drain systems. Traps’ primary role is gas containment, making B correct.

Verified Answer from Official Source:B - the backflow of sewer gases

"Plumbing traps are required to prevent the backflow of sewer gases into occupied spaces bymaintaining a water seal in the drain system." (NCIDQ IDPX Study Guide, Section 2: Building Systems)

Explanation from Official Source:The NCIDQ aligns with IPC standards, noting traps as a critical health and safety feature in plumbing design to protect indoor air quality.

Objectives:

Understand plumbing system functions (IDPX Objective 2.9).

The NCIDQ IDPX exam tests the designer’s understanding of structural concepts, particularly the types of loads that affect building design. Loads are forces that a building must withstand, and they are classified based on their nature and behavior.

Option A (Live loads):Live loads are temporary or movable loads, such as people, furniture, or snow, that can change over time. While they can vary, they are not necessarily dynamic in the sense of rapid application (e.g., earthquakes). Earthquakes and wind loads are not classified as live loads.

Option B (Dead loads):Dead loads are static, permanent loads, such as the weight of the building structure itself (e.g., walls, floors, roof). Earthquakes and wind loads are not permanent; they are transient forces.

Option C (Static loads):Static loads are constant and do not change over time (e.g., the weight of a wall). Earthquakes and wind loads are not static, as they involve rapid, changing forces.

Option D (Dynamic loads):This is the correct choice. Dynamic loads are forces that vary with time and are applied suddenly or cyclically, such as earthquakes (seismic forces) and wind loads (gusts). These loads cause vibrations and require special consideration in structural design to ensure the building can withstand them.

Verified Answer from Official Source:

The correct answer is verified from NCIDQ’s official study materials on structural concepts and load types.

“Dynamic loads, such as earthquakes and wind loads, are forces that vary with time and are applied suddenly or cyclically, requiring specific structural design considerations.” (NCIDQ IDPX Study Guide, Building Systems Section)

The NCIDQ IDPX Study Guide defines dynamic loads as forces that change over time, such as earthquakes and wind loads. This classification aligns with Option D, making it the correct answer.

Objectives:

Understand the types of loads in building design (NCIDQ IDPX Objective: Building Systems).

Apply structural knowledge to coordinate with engineers (NCIDQ IDPX Objective: Coordination).