NASCLA OSHA topics: the 29 CFR 1926 rules to know
29 CFR Part 1926, OSHA's construction standards, is one of the 24 references on the NASCLA Commercial General Building exam. It is also the one you can read free online. Safety does not have its own subject area in the outline, so its questions can sit under General Requirements, Site Construction, Concrete, Metals and others. The rules are numeric and fixed, which makes them some of the quickest points on the exam if you know where they are.
Which OSHA book to bring
PSI's Candidate Information Bulletin (updated 7 Jul 2026) allows either 29 CFR Part 1926, the 2023 edition with the latest available amendments, or PSI's OSHA Excerpts 2025. OSHA publishes the standards online, but phones and tablets go in storage, so bring a printed copy. If you choose the excerpts, check that they include the subparts you plan to tab.
The values to know
Each value below was read in the eCFR text of Part 1926, current to 4 Nov 2026. The wording is ours, not the standard's. Learn the trigger, then tab the section so you can confirm it.
Falls, scaffolds, ladders and stairs
| Situation | Rule | Section |
|---|---|---|
| Unprotected side or edge | Fall protection at 6 ft or more above a lower level: guardrail, safety net or personal fall arrest system | 1926.501(b)(1) |
| Guardrail top rail | 42 in., plus or minus 3 in., above the walking or working level | 1926.502(b)(1) |
| Guardrail strength | The top rail withstands at least 200 lb applied within 2 in. of its top edge, outward or downward | 1926.502(b)(3) |
| Scaffolds | Fall protection for each worker more than 10 ft above a lower level | 1926.451(g)(1) |
| Fall protection training | Training by a competent person, with a written certification record | 1926.503 |
| Stairway or ladder needed | At any point of access with a break in elevation of 19 in. or more and no ramp, runway, sloped embankment or personnel hoist | 1926.1051(a) |
| Portable ladder to an upper landing | Side rails extend at least 3 ft above the landing | 1926.1053(b)(1) |
| Ladder angle | Foot set out about one-quarter of the working length: the 1-to-4 rule | 1926.1053(b)(5)(i) |
Excavations
| Situation | Rule | Section |
|---|---|---|
| Protective system | Needed unless the excavation is entirely in stable rock, or is under 5 ft deep and a competent person sees no sign of a possible cave-in | 1926.652(a)(1) |
| Way out of a trench | Stairway, ladder, ramp or other safe exit in trenches 4 ft or deeper, within 25 ft of sideways travel | 1926.651(c)(2) |
| Spoil and equipment | At least 2 ft from the edge, or held by retaining devices | 1926.651(j)(2) |
| Inspections | Daily by a competent person before work, as needed during the shift, and after every rainstorm or other hazard-raising event | 1926.651(k)(1) |
| Slope with no soil classification | No steeper than 1 1/2 horizontal to 1 vertical, 34 degrees from horizontal | 1926.652(b)(1) |
| Simple slopes 20 ft deep or less | Type A 3/4 : 1, Type B 1 : 1, Type C 1 1/2 : 1 | Subpart P, Appendix B |
Concrete, masonry and steel
| Situation | Rule | Section |
|---|---|---|
| Loads on concrete | None unless the employer has information from a person qualified in structural design that the structure can carry them | 1926.701(a) |
| Protruding rebar | Guarded to remove the impalement hazard | 1926.701(b) |
| Masonry wall under construction | A limited access zone as wide as the wall height plus 4 ft, the full length of the wall | 1926.706(a)(2) |
| Steel erection | Fall protection on an unprotected side or edge more than 15 ft above a lower level; connectors and controlled decking zones have their own paragraphs | 1926.760(a)(1) |
| Loads on steel joists | None until all bridging is installed and anchored and all bearing ends are attached, with one listed exception | 1926.757(e)(2) |
Electrical and hazard communication
| Situation | Rule | Section |
|---|---|---|
| Temporary power | GFCI protection on 120-volt, single-phase, 15 and 20 amp receptacle outlets that are not part of the permanent wiring, or an assured equipment grounding conductor program | 1926.404(b)(1) |
| Hazard communication | Same requirements as the general industry standard, 1910.1200: labels, safety data sheets and training | 1926.59 |
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The competent person
OSHA defines a competent person as someone able to identify existing and predictable hazards who also has the authority to take prompt corrective measures (1926.32(f)). Both halves matter. A worker who spots a hazard but cannot stop the work is not a competent person under this definition. Excavation inspections, scaffold work and fall protection training all rely on one.
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Common mix-ups
- 6, 10, 15. Six feet for general fall protection, ten for scaffolds, fifteen for steel erection. Read which work the question describes.
- Slope ratios are horizontal first. 1 1/2 : 1 is flatter than 1 : 1.
- 4 ft and 5 ft are different rules. 4 ft is the trench exit trigger; 5 ft is the protective system threshold.
- 19 in. is about access, not fall protection.
How to tab it
Tab the index, then the subparts that hold the rows above: C (general provisions, where the competent person definition sits), K (electrical), L (scaffolds), M (fall protection), P (excavations, with its soil and slope appendices), Q (concrete and masonry), R (steel erection) and X (stairways and ladders). See how to tab your NASCLA books for a color plan. The subject-area guides use these rules in context: Site Construction, Metals and General Requirements. Injury recordkeeping sits in a different part, 29 CFR 1904; see the OSHA 300 log.
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Sources
Show the list
- 29 CFR Part 1926, Safety and Health Regulations for Construction, eCFR, current to 4 Nov 2026. Every section and value on this page was checked against it on 5 Nov 2026.
- PSI Candidate Information Bulletin 1458, reference list, updated 7 Jul 2026. Retrieved 5 Nov 2026.
Facts come from the sources listed above. If something has changed, tell us and we will correct it within 2 business days.
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