NCARB PDD Exam Dumps

Understanding the Diagram

The image shows a pump installation detail with various vibration and alignment control devices:

A --- Typically a pipe hanger or suspension support to reduce strain on piping.

B --- Likely a flexible electrical conduit (for pump motor connection).

C --- Spring vibration isolators under the pump base to prevent vibration transmission into the building structure.

D --- A flexible pipe connector (also called a flex connector or braided flexible coupling).

Purpose of Flexible Pipe Connectors

Flexible pipe connectors (D in the diagram) are designed to:

Absorb minor misalignment between connected piping systems.

Reduce stress on pump flanges due to thermal expansion, settlement, or installation tolerances.

Isolate vibration from the pump so that it is not transmitted along rigid piping to the building structure.

This makes them essential in mechanical systems where pumps, chillers, or other vibrating equipment connect to rigid building piping.

Why Other Options Are Incorrect:

A . Pipe hangers/supports --- Maintain alignment and support vertical loads but do not allow for misalignment or vibration isolation in the same way as flexible connectors.

B . Electrical conduit/flexible connection --- Relates to electrical supply flexibility, not piping alignment.

C . Spring vibration isolators --- Isolate vibration from equipment to the floor but do not address piping misalignment.

NCARB ARE 5.0 PDD Study Guide Reference:

Content Area: Integration of Building Materials & Systems --- Mechanical Systems Coordination

Source Reference:

Mechanical and Electrical Equipment for Buildings (MEEB) --- Chapter on Vibration Isolation & Pump Installation

Architectural Graphic Standards --- Flexible Connector & Piping Details

Key Point: Flexible connectors at pumps and equipment protect against misalignment, vibration, and stress transfer to the piping system.

The detail shows a steel runner with sheetrock and screws, typical for drywall suspended ceiling assemblies.

This construction method is commonly used in concrete frame buildings with drywall ceilings suspended below the structural slab.

It helps prevent cracking by accommodating building movement and separating finish materials from structural movement.

Structural steel frame buildings with plaster ceilings typically have different finish and framing details.

Concrete flat slabs with exposed ceilings have no finish requiring such assemblies.

Exposed steel frames without partitions don't need drywall framing.

NCARB ARE 5.0 Review Manual, Materials and Assemblies chapter

Interior finishes and drywall system installation guides (Gypsum Association)

1. Understanding the APA Grade Stamp

The stamp in the exhibit reads:

APA RATED SHEATHING 32/16

15/32 INCH (thickness)

SIZED FOR SPACING

EXPOSURE 1 (can handle temporary moisture exposure)

2. Meaning of '32/16'

The numbers 32/16 are the span ratings for the panel:

32 inches = maximum recommended span for roof sheathing (when applied perpendicular to supports).

16 inches = maximum recommended span for floor sheathing (when applied perpendicular to supports).

These ratings are established by APA (The Engineered Wood Association) based on panel thickness, grade, and allowable loads/deflection limits.

3. Applying to the Question

The question asks specifically for maximum recommended span for use in a floor system. From the stamp:

Floor span rating = 16 inches

Therefore, the correct answer is 16 in.

4. Why Other Options Are Incorrect:

A . 15 in --- Not the value given; 16 in is the rating.

C . 32 in --- This is for roof applications, not floor systems.

D . 108 in --- Not related to APA span ratings; possibly confused with the certification number 'NBR-108.'

5. NCARB ARE 5.0 PDD Study Guide Reference:

Content Area: Building Materials & Assemblies --- Wood Products

Reference Sources:

APA -- The Engineered Wood Association: Panel Span Ratings Guide

Building Construction Illustrated (Ching) --- Plywood and OSB Panel Markings

IBC Chapter 23 --- Wood span and application requirements

The diagram shows a loaded beam with two types of failure indicated:

Location 1 on the top edge shows shear failure --- characterized by jagged cracks or fractures, typically near supports or where shear forces peak.

Location 2 near the bottom edge shows tension failure --- concrete is weak in tension, so cracks develop at the bottom face in a simply supported beam under load.

This matches common structural behavior where:

The top fibers of a beam in bending undergo compression and shear stress.

The bottom fibers undergo tension (where cracks often form).

Shear cracks are usually diagonal and closer to the support (near the ends), tension cracks are vertical and near the midspan.

NCARB ARE 5.0 Review Manual, Structural Systems chapter

Fundamentals of structural analysis and beam failure modes