STSC Scaffolding Erection and Inspection 4 — Questions and Answers
Question 1: When erecting a tubular welded frame scaffold, at what height must the first set of cross braces be installed?
- At the top of the first frame section
- At the base of the first frame section before adding additional frames (Correct answer)
- Only after the scaffold reaches 10 feet
- Cross braces are optional on tubular frame scaffolds
Correct answer: At the base of the first frame section before adding additional frames
Cross braces must be installed at the base of the first frame section to provide lateral stability before additional frames are stacked.
Question 2: What is the minimum wire gauge for wire used to secure scaffold planks in place?
- 12 gauge
- 14 gauge (Correct answer)
- 16 gauge
- 18 gauge
Correct answer: 14 gauge
OSHA requires a minimum of 14-gauge wire when wire is used to secure scaffold planking.
Question 3: A scaffold is being used near overhead power lines. According to OSHA 1926.502, what is the minimum safe distance from uninsulated power lines carrying up to 50 kV?
- 3 feet
- 5 feet
- 10 feet (Correct answer)
- 15 feet
Correct answer: 10 feet
OSHA requires scaffolds to be erected at least 10 feet away from uninsulated power lines rated up to 50 kV.
Question 4: Which condition makes a scaffold plank unfit for use?
- Minor discoloration from weathering
- Knots located in the middle third of the span
- Checks (lengthwise cracks) that do not reduce load capacity
- Split ends extending more than the plank's thickness (Correct answer)
Correct answer: Split ends extending more than the plank's thickness
Split ends that extend beyond the plank's thickness compromise structural integrity and the plank must be removed from service.
Question 5: During a scaffold inspection after a storm, you notice one upright has settled approximately 1 inch into soft soil. What is the correct action?
- Continue use since 1 inch is within tolerance
- Add a mudsill under the affected upright only
- Remove all workers immediately and re-level and re-plumb before resuming work (Correct answer)
- Reduce the load on that side of the scaffold by half
Correct answer: Remove all workers immediately and re-level and re-plumb before resuming work
Any settlement that causes the scaffold to go out of plumb requires immediate evacuation and correction before work resumes.
Question 6: What is the purpose of the 'green tag' system commonly used in scaffold management programs?
- To indicate that the scaffold is made of environmentally certified materials
- To show that a competent person has inspected the scaffold and it is safe for use (Correct answer)
- To mark scaffolds that require fall protection for users
- To identify scaffolds rated for heavy-duty loads only
Correct answer: To show that a competent person has inspected the scaffold and it is safe for use
A green tag indicates a competent person has inspected the scaffold and authorized it for safe use.
Question 7: When must scaffold erectors wear personal fall arrest systems (PFAS) or be protected by a safety net?
- Only when working above 10 feet
- Whenever it is technically and economically feasible to do so (Correct answer)
- Always, regardless of height
- Only when erecting suspended scaffolds
Correct answer: Whenever it is technically and economically feasible to do so
OSHA 1926.502 requires fall protection for scaffold erectors when it is both technically and economically feasible, based on a site-specific analysis.
STSC Scaffolding Erection and Inspection 4
When erecting a tubular welded frame scaffold, at what height must the first set of cross braces be installed?