Chapter 24 — Exercises

Work these with the chapter closed where you can. Where a question asks for a regulatory requirement, answer by topic and function — the subpart that owns it and what it requires — rather than by section number, and where you are unsure, write down where you would go to look it up. That habit is the exercise.

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

Selected answers appear in Appendix J. Calculation items have their numeric answers in a <details> block here.

Part A — Conceptual Understanding ⭐

A1. State the chapter's threshold concept in your own words in two sentences, then give one example from your own experience — a job, a shop, a kitchen, a warehouse, anywhere — of a hazard that was an output of an upstream decision rather than a local failure.

A2. Name the Focus Four. For each one, name the highest-leverage control and identify which level of the hierarchy of controls it occupies.

A3. What is the difference between a competent person and a qualified person? Which half of the competent-person definition do people most often forget, and why does forgetting it make the designation worthless?

A4. Explain the General Duty Clause in plain language, including the four elements that have to be present for it to apply. Then give an example of a hazard on a building site that no specific standard cleanly addresses.

A5. Give the four fall protection trigger heights covered in §24.4.1 and name the activity or subpart each one belongs to. Why is a superintendent who says "six feet, always" wrong in both directions?

A6. What are the five components of a fall clearance calculation, and from what point are they measured?

A7. Explain why a rising near-miss report count is usually good news. Write the explanation as a mechanism, not as a slogan — someone who has never heard the idea should be persuaded by your paragraph.

A8. Under the multi-employer worksite framework, name the four employer roles and give a one-line construction example of each. Which one is a general contractor most often, and what standard is that role held to?

A9. Why is PPE last in the hierarchy of controls? Give the mechanical reason, not the ranking.

A10. What is the difference between a corporate safety manual and a site-specific safety plan? State the one-sentence test that distinguishes a real site-specific plan from a relabeled corporate one.

Part B — Applied Analysis ⭐⭐

B1. A superintendent tells you the site's safety performance is excellent: "Zero recordables in fourteen months and zero near-misses reported all year." Write the four questions you would ask, in order, and say what answer to each would worry you.

B2. A subcontractor's JHA for structural steel erection lists nine steps. Every single control in the "Controls" column is one of: hard hat, safety glasses, gloves, harness, high-visibility vest. Nothing is wrong with any of those items. What is wrong with the JHA, what does it tell you about how it was produced, and what specifically would you send back?

B3. Your project's weekly leading-indicator dashboard shows the following over four weeks. Interpret it. What is happening, what would you predict, and what would you do on Monday of week 4?

B4. An electrician is found working from the top step of a 6-foot stepladder in a mechanical room, reaching overhead to land a circuit in a panel he has verified de-energized. His foreman's response is "I've told him about that ladder three times." Apply the substitution test from §24.10. What is the likely system problem, and what would you ask to find it?

B5. Meridian's Division 01 requires 100% tie-off above six feet on the Northgate project, with no exception for guardrail-protected areas. Your steel erector, operating under Subpart R, points out that this exceeds what the standard requires for their scope and will slow decking substantially. Both parties are right. Walk through how you would resolve it, and name the document the resolution has to end up in.

B6. Kestrel's project safety file shows twelve consecutive weekly site inspections, each one signed, each one with the "Findings" section blank. The superintendent says this proves the site is well run. Give the opposite reading, and explain how an OSHA compliance officer or a plaintiff's expert would characterize that file.

B7. A general contractor discovers that its drywall subcontractor's foreman has been telling injured workers to see their own doctor and pay out of pocket, offering to "make it up on hours." No injury has been formally reported in nine months. List every problem here — regulatory, contractual, ethical, and data — and say what you do in the first twenty-four hours.

B8. During commissioning on Northgate, the permanent electrical system is partially energized while three trades are still working in the same rooms. Describe the hazard this creates, name the two documents that should exist before energization, and say who has to sign each one.

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

C1. Fall clearance. A worker will be tied off to an anchor point 16 feet above the level below, using a 6-foot shock-absorbing lanyard anchored at his dorsal D-ring level. Use the illustrative values from §24.4.1: free fall 6.0 ft, deceleration 3.5 ft, harness stretch 1.0 ft, worker height below D-ring 5.0 ft, safety margin 2.0 ft.

(a) Compute the required clearance below the anchor. (b) Does the system work at 16 feet? By how much? (c) The foreman proposes moving the anchor down to the walking surface at the worker's feet so it is easier to reach. Recompute and state what happens. (d) State the control you would actually use, and why.

C2. TRIR and DART. A project has worked 268,000 craft man-hours and recorded 4 recordable cases, of which 2 involved days away or restricted duty.

(a) Compute TRIR and DART. (b) The project will finish at 340,000 hours. If no further cases occur, compute the final TRIR. (c) If one more recordable occurs before completion, compute the final TRIR. (d) In one sentence, say what (b) and (c) together tell you about using TRIR to judge a program.

C3. EMR and the bid. A contractor's annual workers' compensation manual premium is $1,640,000. Compute the annual premium at an EMR of 0.82, 1.00, and 1.21, and the three-year cost of moving from 0.82 to 1.21. Then answer: an owner's prequalification requires an EMR below 1.00. What is the cost of crossing that line that does not appear in your premium calculation?

C4. Write a complete JHA. Produce a full job hazard analysis, in the format of §24.6 (step / hazard / control with hierarchy level / who verifies and when), for setting a rooftop air handling unit by mobile crane onto a curb on a two-story building, adjacent to an occupied sidewalk. Minimum eight steps. At least one control must be at the elimination or substitution level. Include a rescue provision and a wind limit stated as a number.

C5. Price the controls. You are given an acceleration option: bring a second finish crew of 18 workers into a floor currently occupied by two other trades, for five weeks, at a priced cost of $62,000. Build the required-controls list with prices — overhead protection, barricades, a floor coordinator, revised JHAs, doubled cleanup, additional temporary power and lighting — using defensible assumptions you state explicitly. Produce the all-in number and say how many of the promised days you think it actually delivers, and why.

C6. Write a toolbox talk. In the five-part structure from §24.7, write a complete five-minute talk (roughly 550–700 words of spoken text) for a crew starting roof work on a two-story building on Thursday, where the roofing includes hot work at the flashings and the roof edge has no permanent parapet. Include a specific story, three concrete actions, and a named person behind each action. Read it aloud and time it.

C7. Complete a safety impact review. Take the eight questions from §24.11 and complete the one-page review for the following directive: "Move the MEP overhead rough-in on levels 2 and 3 forward by three weeks so that drywall can start earlier; add Saturday work for the mechanical and electrical trades for six weeks." Invent reasonable project details and state them. Produce a priced control list and a recommendation.

Part D — Judgment and Ethics ⭐⭐⭐

D1. You are the project manager. Your superintendent tells you, privately, that the site's best masonry foreman — a man who has been with the company eleven years and has never had an injury on his crew — has twice told his people to "just get it done" on a scaffold that had not been re-tagged after a modification. Nothing happened either time. What do you do, in what order, and what is the specific thing you must not do if you want anybody to tell you the next one?

D2. A worker reports a near-miss: he almost stepped into an unguarded floor opening because he was walking backwards carrying a sheet of plywood, and he admits he was not looking and was not supposed to be carrying it alone. Your safety coordinator wants to write him up for the unsafe act. Make the argument against, make the strongest argument for, and then decide. If you decide against discipline, write the two sentences you say to the safety coordinator so the decision does not read as indifference.

D3. Your project's TRIR is 0.00 at eleven months. Reviewing the file, you find two injuries that were characterized as first-aid-only: a laceration closed with adhesive strips at an urgent care, and a back strain where the worker was assigned "light duty" recorded as no restriction. You are not certain either one is recordable. Describe the process you follow, who you involve, and what you do about the eleven months of reporting that has already gone to the owner. Then state the ethical line and where these two events sit relative to it.

D4. Kestrel's executive team proposes a company-wide safety bonus: $500 per employee per year, paid if the company's TRIR stays below 2.00. The CFO likes it because it is cheap and measurable. Write the memo arguing against it — in one page, with the mechanism spelled out — and propose the alternative with the same budget.

D5. You are the owner's representative. Your contractor's site is visibly disorganized: material in egress paths, a stale scaffold tag you happened to notice, and two workers on a scissor lift with the gate chained open. Your contract makes safety the contractor's sole responsibility, and your attorney has warned you about assuming duties by directing safety. What do you do, what do you say, and — precisely — what do you put in writing?

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

M1. With Chapter 14 and Chapter 29. You are given a recovery schedule that pulls four activities forward and runs three of them concurrently in the same zone. Using the CPM logic and the safety impact review together, identify (a) which activities now have negative float, (b) which pairs create overhead-work-above-occupied-work exposure, and (c) how you would state the required controls as schedule constraints — activity logic, not rules — so they survive the next update.

M2. With Chapter 19 and Chapter 16. Write the safety section of a subcontract scope sheet for a scaffold contractor, covering: competent-person designation and after-hours availability, modification control, tagging, who may alter the scaffold, the flow-down of your site-specific safety plan, and the backcharge mechanism for violations. Then identify the scope gap this creates with the masonry and electrical scope sheets, and write the sentence in each that closes it.

M3. With Chapter 20. A crew of 12 is put on 60-hour weeks for eight consecutive weeks to recover schedule. Build a two-column table: the left column is the productivity consequence you learned in Chapter 20; the right column is the safety consequence from this chapter. Then answer: at what week would you stop, and what evidence would you use to defend stopping to a VP who is watching the recovery curve?

M4. With Chapter 6. Add safety to a project risk register. Write five risk entries in the Chapter 6 format — risk, probability, impact, owner, response, contingency — where the risk is a hazard-generating management decision rather than a field hazard. (Example: "Directed acceleration in the finishes phase creates trade stacking on levels 2–4.") State how you would price the contingency.

M5. With Chapter 23. A nonconformance report says "the installer set the curtain wall anchors out of tolerance." An incident finding says "the worker stepped onto an unsecured plank." Explain why these are the same species of non-answer, then rewrite both as findings that identify the producing system. Finally, design one shared corrective-action tracker that would serve both the quality and safety programs, and say what fields it needs.

M6. With Chapter 21 and Chapter 18. Redraw the Northgate internal traffic control plan from §24.4.2 for a site with two gates and a crane that must be relocated twice during the project. Identify every point where a pedestrian route and an equipment route would otherwise intersect, and state the engineering control at each one. Then state which of your decisions is a productivity decision, which is a safety decision, and how many are both.

Part E — Research and Extension ⭐⭐⭐⭐

E1. Find out whether the state you live in operates an OSHA-approved state plan, and whether it covers private-sector construction. If it does, identify three requirements it imposes that federal OSHA does not, and describe what each one would change about how you run a job there — crew composition, written programs, permits, or reporting. Cite the state agency by name and say where you found the information.

E2. Read three incident investigation reports from NIOSH's Fatality Assessment and Control Evaluation (FACE) program, choosing three different Focus Four categories. For each: build the five-whys chain yourself from the facts in the report, apply the substitution test, and classify each of the report's recommendations as proximate or systemic. Then answer the hard question: how many of the recommendations across all three reports would have prevented the class of failure rather than the specific instance?

E3. Obtain a real site-specific safety plan — from an employer, an internship, a public bid document, or a public agency's posted contractor submittals. Score it against the fourteen-section table in §24.5. Then apply the chapter's test: could a new foreman run tomorrow's work from it? Write a one-page critique naming the three sections that are strongest and the three that are relabeled corporate boilerplate, with evidence for each judgment.