Chapter 10 Quiz

C. $17,290,000 ÷ $40,000,000 = 43.2%; $17,290,000 ÷ $47,500,000 = 36.4%. The GMP denominator also includes general conditions, insurance, contingency, fee, and escalation, so it is always the lower figure. For benchmarking against past projects, use direct cost of work — it is the only denominator that compares construction to construction.

B. 30 inches. 13'-6" = 162". 162 − 24 (structure) − 108 (9'-0" ceiling) = 30".

B. Gravity drainage has essentially zero degrees of freedom: its slope is fixed by code and its invert elevations are fixed at both ends. Coordinate in order of decreasing constraint — the system with the fewest options claims its space first, because it is the one least able to recover from a bad decision.

B. The hydraulic calculation is a proof tied to the exact pipe sizes and routing: pressure is consumed by friction and elevation, so changing the route changes every downstream subtraction. Domestic water can absorb an extra elbow and a two-foot offset without a resubmittal. The sprinkler main cannot — which is why it is the least flexible pipe in the ceiling.

C, roughly 16 inches. The tray needs clear working space above it so cable can be laid in from overhead and circuits added later. Always coordinate the maintained envelope — the object plus insulation, hangers, and required access and clearance — never the catalog dimension.

C. The design drawings never resolved the third dimension — a mechanical plan shows a line, not a 46-inch insulated envelope at a specific elevation. After sign-off, "but the mechanical drawing shows it here" is not an argument about location. Specifications and drawings continue to govern everything else.

C. $223,650. 21 CD × $10,650/CD, where $10,650 = $5,150 extended general conditions + $5,500 liquidated damages. (Answer D is the Northgate steel delay figure — 23 days, not 21.)

B. Life safety (egress lighting, exit signs, fire alarm, elevator recall), critical (patient-care receptacles, task lighting, isolated power), and equipment (selected HVAC, medical gas alarms, elevators, sump). Each has its own transfer switch and its own required response time. The framework comes from the National Electrical Code's health-care-facilities article and NFPA 99 — verify which editions your AHJ has adopted.

B. Brazing copper without an inert purge produces oxide scale inside the pipe that cannot be cleaned out. The remedy is replacement of the affected piping. This is why installer credentials (commonly referenced to the ASSE 6000 series of medical-gas personnel standards) are verified before work begins, not after.

B. The work is space-constrained, not labor-constrained. You cannot put twelve people where three fit. Crowding a ceiling causes trade stacking, which causes rework and near-misses — which is why schedule pressure in a congested ceiling is a safety issue and not only a cost issue.

B. Fire alarm is tested device by device in the fire marshal's presence and can only happen when the building is essentially complete. On Northgate the certificate of occupancy is September 24, Year 2 — six days after substantial completion — and those days belong to fire alarm, fire pump, sprinkler acceptance, and the life-safety walk.

B. Raw counts are noise. A filtered number produced by a well-built rule set — Grace's 1,840 on Northgate — is the actionable figure, and the shape of the curve across rounds (roughly 40–70% reduction per round, with soft/access issues dominating the last round) is how you know the process is working.

False. On Northgate it was priced at $314,000 — the most expensive of the four options — and by the time coordination surfaced the conflict it was unavailable at any price, because steel topped out on November 12, Year 1. It is a design-phase option only.

False. On Northgate, dropping Corridor C to 8'-2" was priced at $41,200 in soffit transitions at 34 door openings and 6 alcoves, revised reflected ceiling plan, framing, drywall, finish, and fixture relayout — and it still did not solve the problem, because four systems remained homeless for lack of corridor width.

False. Layered 2D drawings worked for decades and still work on simple buildings with generous cavities. What they cannot resolve is the third dimension. The error in Case Study 10-2 was not choosing the 2D method; it was choosing a method without ever running the cavity arithmetic that would have shown the method was insufficient for that building.

False. Functional performance testing begins on July 20, Year 2 on Northgate. Commissioning as a process begins in design with the owner's project requirements and the commissioning plan, continues through submittal review, and includes installation verification checklists filled out during rough-in. A project whose commissioning agent first sees the job at functional testing has bought a very expensive punch list.

False. They reduce labor risk by moving work out of overhead conditions into a shop, but they convert a coordination risk into a fabrication risk: if the model is wrong or the as-built structure does not match it, you have manufactured the error 40 feet at a time. Prefab is appropriate where coordination is disciplined and the building has been verified — commonly by laser scanning — and dangerous where it is not.

False. It is the one MEP scope you genuinely cannot fix later. A misplaced floor drain becomes a saw-cut through a structural slab, a compromised vapor retarder, and a flooring failure two years later. The early-schedule feeling of ease is exactly what causes teams to skip the pre-pour walk.

Available cavity = floor-to-floor height − total structural depth − required finished ceiling height (minus any raised floor, thick topping, or suspended soffit).

A section cut shows only the systems that happen to cross at that one location, so it silently excludes every system that was already squeezed out of the corridor for lack of width. On Northgate's Corridor C, the supply and return ducts consumed 85 of 96 inches of width, leaving 11 inches — which could not accept the cable tray, conduit rack, med-gas rack, or domestic water. A solution that relieves the section while leaving four systems homeless is not a solution, which is exactly why lowering the ceiling ten inches did not fix a nine-inch shortfall.

Coordination sign-off → fabrication release (the shop will not cut metal against an unsigned model, and it has other customers in its queue) → fabrication and delivery (a vendor's production rate, not a crew you can double) → overhead rough-in (space-constrained; adding bodies to an 8-foot corridor reduces productivity) → in-wall and above-ceiling inspections (the AHJ's calendar, not yours) → drywall close-in (cannot legally start before the inspection passes) → ceilings → paint, flooring, casework, devices → startup → commissioning (tests complete systems) → substantial completion. Every relationship is finish-to-start with a physical or regulatory reason behind it, so there is no soft logic anywhere to absorb the shift. On Northgate: 21 CD × $10,650/CD = $223,650.

Mechanism: low-voltage scope is scattered across many specification divisions and many drawing series — some in Divisions 27 and 28, some in the electrical drawings, some in the equipment drawings, some in the owner's separate vendor contracts, and some appearing only as an unspecified device symbol on an architectural sheet. The owner frequently buys part of it directly through IT, security, or AV purchasing. So "who furnishes the camera and who pulls the cable to the head-end?" has four plausible answers and everyone assumes it is someone else.

Fix: a scope matrix built at buyout — a row for every low-voltage system and a column for furnish, install, terminate, program, test, and warrant — signed by every party including the owner, and attached to the subcontracts as an exhibit rather than kept as a memo.

Action 1 — Run both checks on every proposal before discussing any of them. Flattening the duct increases its width; compute the new width against the 9 inches of remaining plan clearance before anyone argues about it. Lowering the ceiling relieves the section; compute whether the systems currently excluded for width can then be accommodated. Most proposals die on arithmetic, and doing the arithmetic first saves the meeting.

Action 2 — Apply the routing priority convention and name the constrained system. The sprinkler subcontractor's silence is not neutrality; it is a negotiating position. If his main is the reason another system has nowhere to go, the convention says he is more flexible than the trunk duct and less flexible than the tray, and that determines the order in which people give way — not who spoke up.

Action 3 — Generate at least four options and price each twice, in direct cost and in days at your daily exposure rate, and test each against the whole problem rather than the section you drew. Include at least one you expect to reject; it clarifies the comparison and it shows the owner you looked.

Action 4 — Decide, in writing, with a date, and file any permit action the same day. A coordination decision that does not produce a revised model, a signed decision record, and — where a reroute triggers a recalculation — a permit revision filed immediately, has not actually been made.

On paper at the end of the week: a one-page decision record naming the conflict and its governing dimensions, the four priced options with direct and schedule cost, the selection and its three-sentence justification, the cost allocation by party with the contractual basis for each allocation, any contingency draw with the balance before and after, the permit action and its filing date, and the sign-off date the decision protects.