Construction safety terms glossary for the CHST
Exact meanings matter in construction safety. Knowing the difference between a competent and a qualified person, or between an action level and a permissible exposure limit, matters. This glossary groups twenty construction safety terms by what they help you decide, gives each a one-line meaning and links a full page with an original drawing, an example and the mix-ups that cost points.
Every explanation here is in our own words. OSHA rules are cited by 29 CFR section number, and we never reproduce standard text. Use your own copy of Part 1926 and Part 1904 when you study.
People and planning
Who does what, and how a task is planned before it starts.
| Term | In one line | Full page |
|---|---|---|
| Competent vs qualified person | Can spot hazards and fix them on the spot, versus proven know-how in a subject | Competent vs qualified person |
| Hierarchy of controls | Elimination, substitution, engineering, administrative, PPE, in that order | Hierarchy of controls |
| Job hazard analysis | Task steps, the hazards in each and a control for each hazard | Job hazard analysis |
| Qualified rigger | The rigging skill Subpart CC asks for inside the fall zone | Qualified rigger |
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Emergency Preparedness, Incident Investigation, and Response
On a building under construction, what is the longest allowed travel distance from any point of the protected area to the nearest fire extinguisher?
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Measuring performance
What the numbers say about past harm, and what they miss.
| Term | In one line | Full page |
|---|---|---|
| TRIR vs DART | All recordable cases per 200,000 hours, versus only days away, restricted or transferred | TRIR vs DART |
| Near miss | An event that could have hurt someone and did not | Near miss |
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Health hazards and exposure
How exposure is measured and what the limits mean.
| Term | In one line | Full page |
|---|---|---|
| Permissible exposure limit | OSHA's legal cap on exposure, usually an 8-hour average | Permissible exposure limit |
| Action level | The lower number that starts monitoring and medical duties | Action level |
| Time-weighted average | Exposure spread over the whole shift and divided by 8 | Time-weighted average |
| Silica Table 1 | Set controls for common dusty tasks that replace exposure assessment | Silica Table 1 |
| Hazard communication | Written program, labels, safety data sheets and training | Hazard communication |
| Safety data sheet | The 16-section reference that comes with a hazardous chemical | Safety data sheet |
Falls and falling objects
Protecting the worker at the edge and the people below.
| Term | In one line | Full page |
|---|---|---|
| Fall arrest vs fall restraint | Stopping a fall after it starts, versus never reaching the edge | Fall arrest vs fall restraint |
| Guardrail system | Top rail, midrail and posts at an open edge | Guardrail system |
| Toeboard | The low board that keeps tools and material from falling on people below | Toeboard |
Energy, spaces and fire
Hazards that need isolation, testing or a permit before work.
| Term | In one line | Full page |
|---|---|---|
| Lockout/tagout | Isolate the energy, lock or tag it, verify before work | Lockout/tagout |
| GFCI vs assured grounding | Two legal ways to protect workers on temporary power | GFCI vs assured grounding |
| Permit-required confined space | A confined space with a serious hazard such as a bad atmosphere | Permit-required confined space |
| Excavation protective systems | Sloping, shoring or shielding against cave-ins | Excavation protective systems |
| Hot work | Welding, cutting and grinding, with permits and a fire watch | Hot work |
How these terms map to the CHST
The CHST blueprint has four domains: hazard and risk identification and control (36.6%), safety program development, implementation and sustainment (22.5%), leadership, communication and training (21%), and emergency preparedness, incident investigation and response (19.9%). Many of the terms above relate to the first domain. Recordkeeping and incident causation topics are in the program domain (22.5%); fire protection and emergency action plans are in the emergency domain (19.9%). The CHST exam outline explains each domain.
Practice with the tools
- OSHA incident rate calculator: TRIR, DART and lost time rates from cases and hours.
- Noise dose calculator: dose and 8-hour TWA from hours at each level.
- Trench sloping calculator: slope and top width from depth and soil type.
- Fall clearance calculator: the distance a personal fall arrest system needs below the anchor.
- Ladder angle calculator: base setback and ladder length for the 4 to 1 rule.
- Scaffold tie calculator: tie spacing and the 4 to 1 height to base ratio.
Drill the definitions with the free CHST flashcards, and see the math in one place in the CHST formulas guide.
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Sources
Show the list
- 29 CFR Part 1926, Safety and Health Regulations for Construction, OSHA.
- 29 CFR Part 1904, Recording and Reporting Occupational Injuries and Illnesses, OSHA.
- CHST Examination Blueprint (CHST5, V.2022.04.12), Board of Certified Safety Professionals.
Facts checked 26 October 2026 against the sources listed above. If something has changed, tell us and we will correct it within 2 business days.
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