Chapter 36 — Exercises

Work these with the chapter open the first time and closed the second. 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 analysis · ⭐⭐⭐⭐ research and extension

Part A — Conceptual Understanding ⭐

A1. In one sentence each, state what the energy code binds you to and what a rating system binds you to. Then name the enforcement authority for each and the consequence of failing each.

A2. Explain the chain by which a model energy code becomes an enforceable requirement on your job site. Why is "the energy code" always a local question?

A3. Distinguish the prescriptive and performance compliance paths. Which one converts a design assumption into a contractor workmanship obligation, and by what mechanism?

A4. Define prerequisite and credit in a rating system, and state the consequence of missing each one.

A5. What is the difference between nominal and effective R-value? Name three thermal bridges you would expect to find on a steel-framed commercial building.

A6. What is a certified diversion rate, and why does the receiving facility matter more to your waste program than your field crews do?

A7. Explain the difference between an EPD and a certification. What does an EPD tell you, and what does it deliberately not tell you?

A8. Give the sequencing rule for wet work and absorptive materials, and explain what physically goes wrong when it is violated.

A9. Name three things about a building's environmental performance that a general contractor genuinely cannot influence, and say when in the project life cycle each of them was decided.

A10. Why is fire-safing at a slab edge not an air barrier? What does that imply about how you read a detail that shows one and requires the other?

A11. Name the four buckets you would investigate when a certified building underperforms its energy model. For each bucket, give one concrete example of a finding you would expect to see, and say which party is best positioned to have prevented it.

A12. Explain, in plain language a foreman would accept, why an air-leakage failure found at the mockup costs one dollar and the same failure found after occupancy costs eighty-four. Do not use the word "prevention."

A13. What is the difference between fundamental and enhanced commissioning, in terms of what each one actually verifies? Name two failures that only the enhanced scope would catch.

A14. Why is the phrase "the contractor shall achieve Gold certification" a problematic contract obligation even for a contractor that performs perfectly? State the fix in one sentence.

Part B — Applied Analysis ⭐⭐

B1. Your owner cancels the certification pursuit in month nine to save money. Working from the specification, the code, the subcontracts, and any local ordinance, write the four-step process you would follow before telling the field anything. Name a specific requirement that will survive the cancellation and explain why.

B2. A mechanical subcontractor proposes a rooftop unit substitution with a shorter lead time. The submitted efficiency exceeds the specified minimum. The project is on the performance compliance path. Write the transmittal note you attach when you route the submittal, in no more than three sentences, and explain in a paragraph what each sentence is protecting you from.

B3. You are handed a wall section for a steel-stud, continuous-insulation exterior wall and asked whether it complies with the energy code. List, in order, the five questions you must answer before you can respond — and note which of the five you can answer yourself and which require the engineer of record.

B4. Your project's waste hauler is acquired by a larger company in month nine. Nothing about your site changes. Describe the three ways this can silently damage your diversion rate, and write the one clause you wish you had put in the hauling agreement at buyout.

B5. Rank these five findings by how much you would expect each to hurt whole-building air leakage, and justify the ranking: (a) 400 LF of unsealed transition between two cladding systems; (b) 60 small penetrations through the field of a wall, each caulked but not gasketed; (c) an unsealed 3-inch gap around a roof hatch; (d) 1,800 LF of unsealed slab edge behind interior framing; (e) an exterior door with a worn sweep.

B6. Read the LEED credit categories in §36.3. For a two-story municipal community center on a flat suburban site with a large parking lot, name the three categories in which you would expect the design to score poorly and the two in which the contractor's execution matters most. Explain each.

B7. A subcontractor tells you the FSC-certified lumber is "on its way and we'll get you the paperwork after." Explain precisely what could go wrong and what you require before that material is installed.

B8. Your project is required to conduct a whole-building air-leakage test three weeks before the enclosure milestone. Write the six-item checklist of things you want done before the test date so that a failure is diagnosable rather than merely embarrassing.

B9. You are the project engineer on a 96,000 SF office building. It is week 12. The temporary heat plan calls for four propane-fired direct-vent heaters on Levels 1 and 2, and the enclosure — including a fully sealed air barrier — will be complete on Level 1 in week 15. Nobody has revised the temporary heat plan since it was written at mobilization. Write the memo you send, name the specific hazard, name the three controls you require, and say who must sign off before the first heater runs inside a sealed area. Then explain why this is a scheduling problem and not only a safety problem.

B10. A rooftop solar array is being added to a building with a manufacturer-warranted TPO membrane roof already installed. The solar subcontractor's proposal shows 140 mechanically attached racking feet. Working from §36.7.3, list every approval, coordination step, and document you require before that subcontractor sets foot on the roof — and identify which single missing document would expose the owner to the largest uninsured loss.

B11. Your interiors specification requires low-emitting adhesives, sealants, paints, and flooring. Your project is not pursuing any certification. A subcontractor asks whether the requirement still applies. Answer in three sentences, then explain what would have to be true for the answer to be no.

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

C1. Diversion rate. A project generated the following in one quarter. Compute the overall diversion rate.

The specification requires 80%. Is it met? If not, how many tons of additional diversion are required?

C2. The lever. Using the C1 data, suppose the commingled facility's rate drops from 71% to 58% when the hauler reroutes in the next quarter, with all other tonnages unchanged. Recompute the rate. Is the target still met? If not, compute how many tons must be moved from the commingled stream into a source-separated stream at 100% to restore compliance.

C3. Effective R-value. A wall has R-21 batt in 6-inch steel studs at 16 inches on center, plus R-10 continuous insulation, plus R-1.5 for sheathing, gypsum, cladding, and air films. Using a correction factor of one third for the steel-stud cavity, compute the nominal and the effective assembly R-values and the percentage of nominal performance lost. Then state, in one sentence, what you would change in the assembly if the effective value were 12% short of a code requirement.

C4. The three discovery points. A different defect, same principle. A project discovers that 900 LF of window-to-wall transition flashing was installed with a reverse lap. Price the repair at three moments using these unit costs and assumptions:

• At the mockup: revised detail plus benchmark installation of 30 LF, $6,400 total.
• Before finishes: demolition and reinstallation of interior finishes at $19/LF; flashing rework at $54/LF; re-testing $11,000; premium time $9,500.
• After occupancy: the same physical scope at a 1.4 escalation factor, plus after-hours premium of $96,000 and containment of $58,000.

Compute all three totals and the ratio between them. Then write two sentences on what the ratio means for how you spend mockup money.

C5. Certification cost. Build a certification cost table for the Willow Street Community Center ($6.8M, 24,000 SF), scaling the Northgate structure in §36.8 to a smaller, simpler, lower-target public building. Show direct hard cost and contractor soft cost separately, state your assumptions explicitly, and compute cost as a percentage of contract value and as dollars per square foot. Then answer: does soft cost scale linearly with project size? Defend your answer.

C6. SCM schedule trade-off. A cast-in-place structure has nine elevated floors. A high-SCM mix pushes the cycle from 6 work days per floor to 8. The project's exposure to slipping substantial completion is $2,800 per calendar day (the Willow Street rate). Assume 5 work days per calendar week. Compute the added frame duration in work days and calendar days, and the schedule cost. Then name three ways to get the carbon reduction without the schedule cost.

C7. Commissioning on the schedule. Build a CPM fragment for the commissioning and indoor-air-quality closeout sequence on a 24,000 SF building: pre-functional checklists, start-up, functional performance testing, deficiency correction, retest, flush-out, training, and final inspection. Assign durations, define the logic, and identify which two activities you would most want float in front of. State your total duration from commissioning start to substantial completion and compare it to Northgate's 60 calendar days.

C8. The scorecard, and who owns it. You are handed the following draft scorecard for a 24,000 SF municipal community center. Complete the analysis.

1. Total the estimated points and state which certification level that total would support under the version your project is registered for. (Look the thresholds up; do not use a number from memory.)
2. Total the points that are contractor-owned or contractor-influenced. That number is your contractual exposure — say why.
3. The Energy and Atmosphere confidence is marked Low and it is the largest category. Name the three things you would ask the design team for, in writing, to raise that confidence, and say what you would do if the answer came back that the design cannot reach its estimate.
4. Write the two-sentence status note you would put in the monthly OAC package. It must be useful to the owner and it must also function as a record.

C9. Cost of quality, applied to certification. Using the structure from Chapter 23 — prevention, appraisal, internal failure, external failure — categorize each of these Northgate line items and total the four buckets: the sustainability coordinator ($118,000); the whole-building air-leakage test ($27,000); the slab-edge remediation ($236,710); the mockup extension that was never bought ($8,600); commissioning support labor ($96,000); the second air-leakage test ($19,400); material documentation chase ($52,000). Then answer the question the totals raise: what is the exchange rate between the prevention bucket and the internal-failure bucket on this scope, and how would you present that to a project executive who wants to cut the coordinator?

Part D — Judgment and Ethics ⭐⭐⭐

D1. Your owner's contract says "Contractor shall achieve Silver certification," with a $150,000 holdback if it is not achieved. Your month-nine scorecard shows the design credits fall four points short of Silver and no contractor-owned credit can close the gap. Write, in full, the letter you send. Then write, in one paragraph, what you would have negotiated at contract execution to avoid needing to send it.

D2. A subcontractor offers to certify a diversion rate for material hauled to a facility whose certification is a year out of date. He tells you the facility's rate has not changed and the paperwork is "in process." What do you do, and what is the line you will not cross? Name the specific cost of crossing it.

D3. Your project can earn a credit by purchasing a small quantity of a high-cost regionally sourced product that has no functional benefit to the building, at a cost of $34,000, purely for the point. The same $34,000 spent on thermally broken cladding clips would measurably improve the building's performance but earns no point. The owner wants the point. Argue both positions honestly, then say what you would recommend and how you would say it.

D4. During interior finishes, your superintendent tells you a crew has been dry-sweeping and blowing down floors with compressed air for two weeks because the vacuum broke and nobody replaced it. Name every distinct problem this creates — safety, indoor air quality, certification, and specification — and describe the corrective action and the preventive action, in the language of Chapter 23.

D5. A designer's energy model number ends up in your owner's operating budget. You know it is a compliance model, not a prediction. It is not your model and not your budget. Do you say anything? To whom, when, and in what medium? What is the cost of saying nothing, and to whom does that cost fall?

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

M1. (with Chapter 16 and Chapter 19.) Write the scope-sheet section covering sustainability requirements for a single trade package — interior finishes. Cover the material documentation deliverables, the substitution-before-purchase rule, the waste separation obligation, the indoor-air-quality obligations, and the sequencing constraint. Then identify the two scope gaps most likely to open between this package and the mechanical package, and say which subcontract closes each.

M2. (with Chapter 14 and Chapter 29.) Your whole-building air-leakage test fails 21 days before the enclosure milestone. Build the recovery plan: the diagnostic activities, the repair activities, the retest, and the logic between them. Compute the impact on the milestone under two scenarios — repair within float using premium time, and repair that extends the milestone by 9 calendar days at Northgate's $10,650/CD. Recommend one and defend it.

M3. (with Chapter 9 and Chapter 23.) Design the mockup program for an enclosure with three systems — curtain wall, precast, and a stud-framed rainscreen wall. For each mockup, state what it proves, what transition it must include, what test it receives, and what the hold point is before production work may start. Then write the one rule that would have prevented Northgate's slab-edge failure.

M4. (with Chapter 25 and Chapter 31.) A detail shows an air seal as a hatch pattern with a note and no product. Write the RFI. Then, assuming the response adds scope, outline the change order: entitlement, pricing basis, and the two documents you would attach.

M5. (with Chapter 28 and Chapter 40.) Build the cost codes you would create at budget load specifically for the sustainability scope, using the §36.8 line items. Explain which of them are general conditions, which are direct cost, and which will be charged by subcontractors. Then explain how you would forecast the commissioning support line at month twelve.

M6. (with Chapter 6 and Chapter 24.) Add five sustainability-related entries to a project risk register: certification shortfall, air-leakage test failure, material non-compliance discovered after installation, utility interconnection delay for an electrified building, and carbon monoxide accumulation in a sealed building. For each, give probability, impact in dollars or days, the owner of the risk, the response, and the contingency treatment.

Part E — Research and Extension ⭐⭐⭐⭐

E1. Find your actual code. Identify the jurisdiction where you live or work. Determine (a) which model energy code or standard it has adopted, (b) which edition, (c) whether local amendments exist and where they are published, and (d) which climate zone the jurisdiction sits in. Write a one-page memo with the citations to the actual adopting documents. Then answer the question that matters: how would you have found this if you had one afternoon and a project bidding on Friday?

E2. Read a real EPD and a real HPD. Manufacturers publish these openly. Find one of each for a product you have specified or installed. Write a page on what each document tells you, what it does not tell you, what units the impacts are reported in, and what you would have to know to compare two products fairly. Note honestly anything in either document you could not interpret.

E3. Benchmark a building. Using published municipal benchmarking data, or twelve months of utility bills for a building you have access to, compute an energy use intensity. Then find a comparable building type in a published dataset — the EIA's Commercial Buildings Energy Consumption Survey is the standard reference — and write a page comparing them. Where your building differs from the benchmark, say what you would have to know about occupancy, hours, and process loads before you drew any conclusion about how well it was built.