- How To Find The Minimum Dimension For The Joist/Duct Combination In The Building Section Vignette
The NCARB Exam Guides for each division are required reading. In each Exam Guide, NCARB provides a sample passing and failing solution to the graphic vignette(s) in that particular division. Unfortunately, candidates often think that these passing solutions are ideal, when in fact they are merely "passing." Some "passing" solutions contain major errors. What's more, not all of the errors in the failing solutions are noted.
Be sure you have the most recent version of the Exam Guides, effective October, 2014.
We have addressed these inaccuracies, omissions, and poor design decisions in the list below. If you have found an error you feel should be added to the list below, please let us know:
Programming Planning & Practice
Site Zoning Vignette:
There is only one "correct" solution to this problem. Errors in the passing solution are addressed in the text below the solution.
Site Planning & Design
Site Grading Vignette:
In several locations, the sample passing solution violates the requirement that the slope of the regraded portions of the site be at least 2%. The minimum slope requirement is an issue only at regarded portions of the site, typically along the centerline of a new swale. To maintain a 2% minimum slope, you may have up to 50’ between any point on a contour line and the nearest point on the next contour line (see the ‘points’ of the new swales between contour lines 106’, 105’ and 104’).
To correct this solution, simply move the ‘points’ of contour line 105’ closer to the ‘points’ of contour 106’. Then move the ‘points’ of contour line 104’ closer to the ‘points’ of contour 105’. This may require the addition of swale ‘points’ to contour line 103’ to maintain a 50’ maximum between the ‘points’ of contour lines 103’ and 104’.
Site Design Vignette:
In the passing solution, the sidewalk from the Pedestrian Plaza to the main entrance of the Restaurant crosses the access drive from Bentley Avenue. Based on the requirement of "sound design logic" this is not recommended.
The two new Conifer(C) trees at the southeast corner of the parking, and the two new 'C' trees at the northeast corner of the Restaurant are unnecessary. More new 'C' tress than necessary are used to block wind to the Pedestrian Plaza. However, the northwest corner of the Pedestrian Plaza is unprotected from wind.
The Pedestrian Plaza is required to have, "noonday solar access." Because of the shadow created by the Office Tower, the southwest portion of the Pedestrian Plaza does not receive "noonday summer sun."
The Pedestrian Plaza is approximately 1,000 s.f. undersized
The Restaurant is required to have a view of the Pond, which is questionable.
The 'buffer' paving in the center of the parking 'loop' is acceptable but not required by the program.
Please note: In July, 2013, NCARB made some changes to the Site Design program. One of these changes was program item #2, "The Restaurant and Office Tower shall be at least 210 ft apart."
In revising the program, it appears that NCARB neglected to remove the third bullet point under program item #13, "Buildings must be separated by a minimum of 20 ft."
Obviously, if your solution satisfies program item #2, then the third bullet point under program item #13 is satisfied.
In the Failing solution, the Office Tower and the Restaurant are not "at least 210' apart." The Pedestrian Plaza is approximately 1,000 s.f. undersized. The south west portion and the north east corner of the Pedestrian Plaza do not receive noonday summer sun.
Building Design & Construction Systems
In the passing solution, the west handrail at the bottom of the stair comes dangerously close to reducing in the width of egress. In order to maintain the egress width, the distance between the end of the handrail and the north wall must be at least equal to the clear width between the handrails on the stair, in this case 52". As a potential code violation, this could be a significant error. The 12” extension could be turned 90 degrees to the west to avoid the issue.
In the passing and failing solutions, the wall-side handrail on the upper ramp from 30" to 25", is unnecessary.
Stair Design Vignette:
In the passing solution, the problem is solved without using the cut stair tool. The entire solution is shown on the upper level, which is fine. However, knowing how to use the Cut Stair tool correctly is critical. On test day your solution may require it.
Roof Plan Vignette:
In the passing solution, on the east edge of the upper and lower roof the downspouts are partially visible, but the gutters are cut off.
Candidates often establish the minimum elevation of the low edge of the high roof based on the following: Elevation of the high edge of the low roof (14'-0") plus the clerestory (24") plus the thickness of the upper roof assembly (18") = 17'-6". The 19'-0" roof elevation at the south west corner of the Exhibition Room is higher than the required minimum. Don't let the 19'-0" dimension confuse you. In this instance, using the minimum of 17'-6", while maintaining minimum roof slopes of 6:12, would require moving the ridge to the east in order to maintain a minimum height of 9'-6" at the east edge of the roof (at face of chimney).
The roof elevation at the north east corner of the Exhibition Room is obscured by an arrow. It reads 10'-0".
In the failing solution, the upper roof slope is lower than the minimum allowed by program.
Interior Layout Vignette:
According to the NCARB FAQs, the required Turning Space may overlap the Maneuvering Clearances at Doors, but NOT the door swing or the door itself. In the passing solution, no Turning Space is available in LCR. Although, by changing the furniture layout, the Turning Space fits in the north-east corner.
The west chair at the Table For Four (TFF) in JO is likely inaccessible. 3ft is required between the edge of the table and the wall.
In CR, the copy machine would be better located on the north wall. Then, shift furniture on the south wall to the east. This would eliminate the south-east inaccessible (dead) corner.
In the failing solution, the space behind the secretarial desks is inaccessible.
Door to CR should swing into CR. Required Turning Space in CR not provided.
Building Layout Vignette:
In the passing solution, avoid L-shaped rooms if possible, see GR and LM.
The location of TR between EE and E is not 'sound design logic' and causes L-shape for GR.
The double doors at the Lobby entry are acceptable but only one door is required.
Door at the east end of CO (1st Floor) is unnecessary. Exiting through the east stair is sufficient.
CR has two doors. Only a single door to the CO is required. The door to the east may be an attempt to satisfy the requirement that CR be, "Near Multi-purpose Room."
In the failing solution, the text below 'floor 1' says, "table/chair storage (TS) room does not directly connect to the circulation system as required by the code." However, it does connect to the corridor (CO).
Additionally, TS has two doors. Only a single door to the CO is required. The door in the north wall to MP may be an attempt to satisfy the requirement that TS be, "Near Multi-purpose Room."
Because of the door locations in the east stair, there is (in reality) a headroom issue when exiting. However, according to NCARB it's irrelevant.
Structural Layout Vignette:
In the passing solution, while the use of bearing walls and lintels is acceptable, many candidates find this problem easier to solve using only steel columns and beams.
In the sample failing solution, Upper Plan, because the "inefficient" joists span in the long dimension, the beam over the clerestory is unnecessary. A joist is sufficient.
Mechanical & Electrical Plan Vignette:
In the passing solution, the rigid duct exiting the supply riser may run straight toward the south wall of the Supply Closet. There is no need for it to jog to the west and then run south along the west wall.
The spacing between the long sides of the 2' x 4' fluorescent light fixtures in the Architect's Office is incorrect.
In the Reception/Secretary, Architect's Office and the Drafting Studio the ceiling grid is off center.
Return-air grilles in the Conference Room and one grille in the Drafting Studio are not supported on three sides.
In the failing solution, the spacing between the long sides of the 2' x 4' fluorescent light fixtures is incorrect.
The west wall of the Architect's Office is underlit.
Construction Documents & Services
Building Section Vignette:
For clarity, the passing and failing solutions are drawn so they do not overlap the floor plans. This is acceptable but takes more time than drawing the solution directly over the plans.
In the passing solution, if we're following "principles of sound design logic," the interior bearing wall should not bear on the 1st floor slab, but directly on a foundation wall below. The slab should stop on one side of the interior foundation wall and continue again on the other side. However, this may be inconsequential. Ceiling to slab dimensions are more critical.
The interstitial spaces are noted, "Correct Depth", but what are they? Here are the numbers;
Laboratory - Slab Thickness=4" + Joist Depth=32" + Duct Depth=20" + Lignting Depth=8" for a total of 64"
2nd Floor - Slab Thickness=4" + Joist Depth=24" + Duct Depth=20" + Lignting Depth=8" for a total of 56"
1st Floor - Slab Thickness=4" + Joist Depth=24" + Duct Depth=24" + Lignting Depth=8" for a total of 60"
In the failing solution, the interior footing should be shown directly up against the bottom of the slab.
Frustration with the multiple choice questions is common. There are two main complaints:
1. 1. Content from other divisions
2. 2. Ambiguous questions/answer choices
1. Regularly, candidates tell me they received questions that seemed better suited for a different division. This isn’t new, but it can be unsettling. While studying any division, try to think broadly about the NCARB content areas. Lighting, in Site Planning & Design, for example? Seems like a Building Systems question, right? Maybe not. Perhaps you’re lighting a park, or a tennis court.
See SP&D Content Area #4, Materials & Technology, 5. Natural and Artificial Lighting.
Traditionally, multiple choice crossover content has been seen mostly between PPP, CDS, and SPD, while Structural Systems seems to be the most autonomous division. But, as you can see in the example above, it can show up anywhere.
2. Whether they’re fresh out of school or have 30 years in the business, candidates sometimes find the questions/answer choices to be ambiguous. They tell me, “None of the answer choices are correct.” Or, “More than one answer choice seems right.” What then? Remember, NCARB is asking you to select, “the best available answer choice.” So, for some reason, one answer choice will be better than the others. Here’s how to narrow it down.
Deconstruct the question for clues to the correct answer. NCARB is not trying to trick you. Their questions are very carefully worded so that one answer choice is the best.
- Does the question refer to a historic building or new construction?
- Is the question region specific? Is the region hot and dry, humid, etc.?
- Does the question refer to a specific phase of a project, Programming, Schematic Design, etc.?
- Does the question or answer include relative qualifiers such as generally, sometimes, or usually?
- Does the question or answer include absolute qualifiers such as always, at no time, or never?
- Improve your odds by trying to eliminate any answer choices that are absurd. If you can eliminate one, you’ve now got a one-in-three chance of guessing correctly.
- Make sure the answer choice agrees with the question grammatically.
- A long answer choice may be correct because of the elaboration required to make it correct.
- Refer to questions you know for clues to answer those you don’t.
- If more than one answer choice seems acceptable, choose the one that is most inclusive. Is one answer choice covered by another?
On the ARE you get 1 point for a correctly answered question, and 0 points for an incorrectly answered question. This means that hard questions are worth the same as easy questions. It may be wise to mark a hard question and come back to it later. But don’t leave any questions unanswered!