Architect Registration Examination Project-Planning-Design Updated Exam

Comprehensive and Detailed Explanation From Exact Extract:

Stratification refers to the layering of air temperatures within a space, where warmer air rises and cooler air stays near the floor. In forced-air heating systems, minimizing temperature stratification is critical to maintaining occupant comfort and energy efficiency. The placement of supply and return air grilles plays a significant role in preventing stratification.

Low supply, low return (Option C) should be avoided because supplying warm air near the floor and simultaneously returning air also near the floor limits effective air mixing. Warm air naturally rises, so if the return grille is also low, cooler air remains trapped above, resulting in poor circulation and uneven temperatures throughout the room. This can cause discomfort, with warmer air accumulating near the ceiling and colder air lingering in the occupied zone.

High supply, low return (Option B) is often preferred because warm air is supplied from high points, then cools and sinks toward the lower return grille, promoting vertical circulation and mixing, reducing stratification.

Low supply, high return (Option A) and high supply, high return (Option D) can be less effective depending on system design, but the critical issue is having both supply and return located low, which restricts air movement and stratification mitigation.

According to NCARB PPD content on building systems and HVAC design, proper grille placement is essential to maintain thermal comfort, minimize energy waste, and comply with indoor environmental quality standards. Effective grille placement harnesses natural convection to ensure even temperature distribution, reducing the potential for hot or cold spots and improving occupant satisfaction.

Comprehensive and Detailed Explanation From Exact Extract:

Enhancing acoustic design requires:

(A) Careful location of noise-sensitive spaces away from noise sources.

(B) Choosing structural floor systems with good sound isolation between floors.

(D) Using exterior barriers (natural or built) to reduce external noise.

(E) Selecting interior finishes with favorable acoustical absorption properties.

Minimizing steel stud framing (C) is not always required; proper detailing can address acoustic issues.

Treatments that decrease sound absorption (F) worsen acoustics.

Comprehensive and Detailed Explanation From Exact Extract:

Adding a green roof with a two-foot soil bed significantly increases the dead load on the roof and affects the uplift forces caused by high winds. This heavier roof mass necessitates additional structural tie-downs or anchorage to resist wind uplift and prevent overturning or structural failure.

The added weight does not inherently increase resistance to overturning (A) or racking (C); rather, it increases loads that require structural reinforcement.

Comprehensive and Detailed Explanation From Exact Extract:

Changing from a pier-and-beam system with an open crawlspace to a slab-on-grade floor has several impacts:

Warmer floors in the evenings (A): Concrete slab-on-grade floors have high thermal mass, which can absorb heat during the day and release it slowly, resulting in warmer floors at night, particularly beneficial in cold climates.

Limited future plumbing flexibility (C): Plumbing embedded in or beneath slabs is difficult to access or modify after construction, unlike crawlspaces that provide easier access to underfloor plumbing for repairs or modifications.

More steel reinforcing (B): While slabs do require reinforcement, this is often comparable or less than the framing required for pier-and-beam floors, so this is not necessarily an impact.

Flooring finishes (D): Slab floors can accommodate many finishes; thus, limitations are generally minimal.

Better moisture control (E): Slabs require moisture barriers and careful detailing to control moisture; crawlspaces can sometimes be easier to ventilate but may allow moisture intrusion if not properly designed.

HVAC ductwork installation (F): Crawlspaces allow ducts to be located under the floor; slabs typically require ducts to be placed above or within conditioned spaces.

Thus, the most significant impacts are warmer floors and reduced plumbing flexibility.