Chapter 10 Exercises

Work these with the chapter closed where you can. Selected answers appear in Appendix J; a few calculation answers are given here in <details> blocks so you can check your arithmetic without checking your reasoning.

Difficulty legend: ⭐ basic · ⭐⭐ applied · ⭐⭐⭐ judgment and integration · ⭐⭐⭐⭐ research and extension

Part A — Conceptual Understanding ⭐

A1. Name the seven scopes that make up "MEP" as the term is used on a commercial project, and identify which one is most commonly bought by a second-tier subcontractor.

A2. Explain the difference between the airside and the waterside of an HVAC system. Name three pieces of equipment on each side.

A3. A colleague says "MEP is 40% of the job." What is the one question you must ask before that statement means anything? Compute both versions for Northgate, whose MEP packages total $17,290,000 against a $40,000,000 direct cost of work and a $47,500,000 GMP.

A4. Define maintained envelope as it applies to ceiling coordination, and explain why a 24-inch by 4-inch cable tray does not occupy 4 inches of ceiling cavity.

A5. State the ceiling cavity budget formula in words. Then name the second check that must be run alongside it, and explain in one sentence why coordination more often fails on the second check than the first.

A6. List the routing priority convention from most constrained to least constrained, and state the single principle that produces the order.

A7. Why does rerouting a sprinkler main have a consequence that rerouting a domestic water main does not?

A8. Name the two rough-in inspection hold points in the interior sequence and state exactly what each one releases.

A9. Distinguish a hard clash, a soft clash, and a workflow clash. Which of the three will an automated clash-detection run never find, and why?

A10. Name the three branches of a healthcare essential electrical system and give one example of a load on each.

Part B — Applied Analysis ⭐⭐

B1. A superintendent tells you the above-ceiling rough-in on level 3 is two weeks behind and he plans to recover by adding a second mechanical crew in the same corridor on second shift. Write the three questions you would ask before approving, and state the one condition under which adding a crew genuinely recovers time.

B2. Your first federated model run returns 34,700 clashes. Your VDC coordinator reports this number to the owner without filtering. Explain what is wrong with that report, what the number probably actually represents, and what you would have asked for instead.

B3. On a job you are estimating, the mechanical drawings show a 36-inch by 18-inch supply main in a corridor. The specification requires 2-inch external duct wrap. The architectural plan shows a 7'-0" clear corridor. Before you do any arithmetic, name the two coordination questions this combination raises, and say which drawing you would pull next.

B4. A sheet-metal subcontractor asks permission to release fabrication for level 2 three weeks before coordination sign-off, arguing that the corridor mains "aren't going to change." List the risks you are being asked to accept, and draft the two-sentence written response you would send.

B5. Your low-voltage package came in at 1.4% of direct cost on a healthcare project where you would expect roughly 3%. Give three specific reasons a low-voltage bid comes in low, and describe the document you would build at buyout to find out which one applies.

B6. During a pre-pour walk for the level-one slab, your field engineer finds that a floor sink shown on the plumbing plan does not appear on the current architectural plan at all. Describe your next four actions, in order, and state which one has a deadline measured in hours.

B7. An owner asks why commissioning cannot simply start the week before substantial completion. Give a two-paragraph answer that explains what commissioning actually is, when it really begins, and what happens to a project that treats it as a final-week activity.

B8. Read the description of the MRI suite in §10.2. List every trade whose work is affected by the MRI's requirements, and for each one name the specific requirement that affects it. Then connect this to Northgate's CO #14 — what did the late equipment selection actually change, and why was the structural impact only part of the cost?

Part C — Calculations and Deliverables ⭐⭐–⭐⭐⭐

C1. Cavity budget — a different corridor. Level 3 of Northgate. Floor-to-floor is 13'-6". The level-4 floor structure here is shallower: a 6¼-inch slab on composite deck carried on nominal 16-inch beams, for a total structural depth of 22 inches. Required finished ceiling in this corridor is 9'-0". The following must pass through the section:

(a) Compute the available cavity. (b) Compute the required stack. (c) State the surplus or shortfall. (d) If the answer is a shortfall, name the one change that produces the largest gain for the least cost, and say what it would cost you contractually.

C2. The plan width check. A corridor is 7'-6" clear. It must carry a 40" × 14" supply duct with 2-inch external insulation, a 30" × 12" return duct (uninsulated), and 3 inches of separation between them for installation. (a) Compute the width consumed. (b) Compute the remaining width. (c) State whether an 18-inch cable tray can run beside them, and if not, name where it goes and what that costs you in ceiling cavity.

C3. Back-schedule a long-lead item. Northgate's main switchgear must be set in the level-one electrical room by December 8, Year 1, so that permanent power can be energized ahead of the winter temporary-heat load. Using these durations — 3 weeks for the subcontractor to prepare the submittal after award, 1 week for Kestrel's review and transmittal, a contractual 14 calendar days for Trellis Engineering's review, a vendor-quoted 30 weeks of manufacture after release, 3 weeks of transit, and 1 week of delivery and staging — determine the latest date the electrical subcontract can be awarded.

Then answer: notice to proceed was March 3, Year 1. How many weeks of buyout time does that leave you, and what does that tell you about when electrical buyout has to start relative to everything else on the job?

C4. Price the schedule consequence. Coordination for level 2 finishes 17 calendar days late. Every downstream activity in the chain shifts by the same 17 days, and substantial completion moves with it. (a) Compute the cost using Northgate's canonical daily exposure. (b) Break the total into extended general conditions and liquidated damages. (c) You are offered an option to recover 11 of the 17 days by paying a fabricator $46,000 in expediting and running premium time on rough-in for $71,000. Is it worth it in pure dollars? (d) Name the non-monetary factor on Northgate that would change your answer regardless of the arithmetic.

C5. Build the MEP percentage table for your own job. Take the Willow Street package in Appendix K. Build a table with one row per MEP package (HVAC, controls, plumbing and gas, fire protection, electrical, low voltage, TAB), an estimated value for each, and three columns: percent of direct cost of work, percent of contract value, and dollars per gross square foot. Then write two sentences on how your percentages compare to Northgate's 43.2% / 36.4% / $131 per SF, and explain the difference in terms of building type.

C6. Write the coordination decision record. Using Case Study 10-1 as your source material, produce the one-page decision record described in that case's "Your Turn." Then produce a second version of the same record for a decision that went the other way — one where the owner-directed solution produced a change order. Compare them and state in one sentence what distinguishes a coordination decision from a change.

C7. Draft the access-panel schedule. A hard (gypsum board) ceiling runs the length of a 90-foot corridor. Above it are 4 VAV terminal boxes with reheat coils, 6 fire/smoke dampers, 2 balancing valves, 3 sprinkler inspector's test connections, and a sanitary cleanout. Build a table listing each device, whether it requires access, the reason (service, code, or testing), and where you would locate the panel. Then answer: what is the cost of discovering this list at commissioning instead of at coordination sign-off, and who pays?

Part D — Judgment and Ethics ⭐⭐⭐

D1. A mechanical subcontractor proposes flattening a duct in the field from 16 inches to 12 inches to clear a beam, without a resubmittal, arguing that "the engineer will never know and the box downstream will still make its air." The ceiling is closing next week. Walk through your decision: what do you do, what do you write, whom do you tell, and what is the specific downstream evidence that would eventually reveal it? Name the professional line being proposed and price crossing it.

D2. Your electrical subcontractor discovers at rough-in that the code-required working clearance in front of a panelboard is occupied by a plumbing riser that was installed first and is already tested and insulated. The plumber says "first in place wins." Under the routing priority convention, who should give way? Under the code, does that question even matter? Explain the difference between a coordination convention and a code requirement, and describe what you would do at 7:00 a.m. the next morning.

D3. You are two weeks from a fire-alarm final test and you know from your own walk that approximately 30 devices are not yet installed. Your superintendent suggests scheduling the test anyway, on the theory that "he'll only spot-check and we'll catch up." Assess this proposal: the immediate consequence, the second-order consequence, and the third-order consequence involving your relationship with the AHJ across future projects. Then write the two sentences you would say to the superintendent.

D4. A project executive proposes cutting the VDC coordination budget on a bid to make the number competitive, and says the estimate can carry the risk in contingency instead. Using the mechanism described in Case Study 10-2, explain why moving coordination from a line item to contingency is not a neutral accounting choice. Then name the one situation in which the executive would be right.

D5. Your commissioning agent, engaged by the owner, finds that an isolation room's pressure relationship is reversed. The mechanical subcontractor argues the design sequence is wrong, not the installation. The owner's licensing survey is in eleven days. Describe how you would run the next 72 hours, including who you would put in a room together, what you would document, and what you would not say in writing until you knew more.

Part M — Mixed and Interleaved Practice ⭐⭐–⭐⭐⭐

M1. (Ch 10 + Ch 7 — reading the documents). Take a single grid intersection in a corridor of any project you can get drawings for. Pull every discipline's sheet for that location — architectural plan, reflected ceiling plan, wall types, structural framing, mechanical, plumbing, fire protection, electrical power, and low voltage. Build a one-page table of what each sheet says is at that location and at what elevation. List every discrepancy. Then answer: how many of your discrepancies are conflicts and how many are simply silences — places where no discipline says anything at all? Which category is more dangerous?

M2. (Ch 10 + Ch 8 — the submittal long pole). The anchor-bolt submittal cost Northgate 23 calendar days by missing a mill rolling slot. The air-handling unit back-schedule in §10.9 shows an award date of June 9, Year 1. Build a single combined table of every long-lead item on Northgate you can identify from the chapter — structural steel, switchgear, generator, air handlers, chillers, elevators — with a column for what it gates and a column for the irrecoverable consequence of missing its release date. Then state the general rule in one sentence.

M3. (Ch 10 + Ch 9 — the interior sequence). Draw the interior finish sequence for a single level, from the completion of overhead rough-in to the installation of casework, as a bar chart or a network sketch. Place both inspection hold points on it. Then insert a 3-week delay at coordination sign-off and redraw. Mark every activity that moves and every activity that does not, and explain why the ones that do not move are the ones that will cause you a trade-stacking problem.

M4. (Ch 10 + Ch 6 — risk register). Write six risk-register entries for MEP coordination on a project of your choice. Each entry needs: the risk stated as a condition and a consequence, a probability band, an impact in dollars, a named owner, a response strategy, and a contingency allocation. At least two of your six must be risks that only surface at commissioning.

M5. (Ch 10 + Ch 4 — contract type). Northgate is CM at Risk with a GMP. Suppose the identical building were procured as a hard-bid lump sum with the same drawings. Answer three questions: (a) who would have run coordination and when; (b) who would have absorbed the $46,100 Corridor C resolution; and (c) how would the 1,840 clashes have shown up differently in the project record? Then state which delivery method makes coordination cheaper and explain the incentive that produces the difference.

M6. (Ch 10 + Ch 5 — legal framework, and forward to Ch 33). In Case Study 10-2, Curtis Boone's delay claim failed on causation even though the architect was genuinely late. Identify the three separate proofs a delay claim requires. Then list, for each proof, the specific contemporaneous document Curtis would have needed to create during the project — not after — to have any chance. For each document, state when it should have been created and how long it would have taken.

Part E — Research and Extension ⭐⭐⭐⭐

E1. Find a real ceiling. Go to a building you have access to — an office, a school, a clinic, a parking garage — and find a place where a ceiling tile can be safely lifted or where the ceiling is open (a mechanical room, a back-of-house corridor, a garage). With permission and without touching anything, photograph or sketch what is above the ceiling. Identify every system you can name. Then answer: what is the actual cavity depth, what is the tightest condition you can find, and does the routing you observe match the priority convention in §10.6? Where it does not, hypothesize why.

E2. Read a real specification. Obtain a publicly available construction specification — many public agencies, school districts, and state facilities departments post complete bid documents online. Find the section that governs MEP coordination (it is commonly in Division 01 as a coordination or project-management section, and often repeated in the Division 21/22/23/26 general requirements). Answer: does it require a 3D model or only "coordination drawings"? Who is designated the coordinator? What is the sequence of submission? What happens, per the specification, when two trades cannot agree? Compare what you find to how Case Study 10-2 turned out.

E3. Map your jurisdiction's inspection reality. Pick a real city or county building department and its fire marshal's office. Using their published information only, determine: how many separate MEP-related permits are required for a commercial building; whether the fire permits are reviewed by the building department or a separate fire authority; what the published plan-review turnaround times are; how inspections are scheduled and what the re-inspection policy is; and whether there is a published fee for a failed inspection. Then write one paragraph on how those facts would change how you build a schedule in that jurisdiction. Note explicitly which of these vary by jurisdiction — all of them do, which is the point.