CDS Equipment Selection & Operations 3 — Questions and Answers
Question 1: During high-reach demolition, what is the maximum recommended working height relative to the equipment's rated reach to prevent tip-over?
- 100% of rated reach
- No more than 85% of rated reach (Correct answer)
- 120% of rated reach
- 50% of rated reach
Correct answer: No more than 85% of rated reach
Operating at no more than 85% of rated reach preserves stability margin and accounts for dynamic loads from debris impact.
Question 2: Which piece of demolition equipment is specifically designed to reduce large concrete slabs into transportable rubble on-site?
- Compactor roller
- Mobile jaw crusher (Correct answer)
- Vibratory plate
- Clamshell bucket
Correct answer: Mobile jaw crusher
Mobile jaw crushers process oversized concrete rubble into graded aggregate that can be reused or hauled efficiently.
Question 3: When operating a demolition excavator on soft or saturated soil, the supervisor should first:
- Increase bucket size to speed up work
- Install timber mats or steel plates to distribute ground pressure (Correct answer)
- Remove tracks and use wheeled undercarriage
- Reduce swing speed only
Correct answer: Install timber mats or steel plates to distribute ground pressure
Timber mats or steel road plates spread equipment weight to prevent sinking or tipping on soft ground.
Question 4: A dust suppression water cannon mounted on demolition equipment primarily targets which hazard?
- Structural vibration
- Airborne silica and debris dust (Correct answer)
- Fuel spill containment
- Noise emissions
Correct answer: Airborne silica and debris dust
Water cannons suppress respirable silica dust generated when concrete and masonry are broken, protecting workers and surrounding areas.
Question 5: What key pre-operation check must be performed on a hydraulic breaker (hoe ram) before beginning work?
- Inspect boom paint condition
- Verify hydraulic oil flow rate and accumulator nitrogen charge (Correct answer)
- Test the cab radio
- Check fuel additives
Correct answer: Verify hydraulic oil flow rate and accumulator nitrogen charge
Hydraulic breakers require correct oil flow and nitrogen pre-charge in the accumulator to strike efficiently without damaging the carrier.
Question 6: When a demolition supervisor must choose between a long-reach excavator and a high-reach excavator, the primary differentiating factor is:
- The color of the equipment
- Whether the work requires horizontal reach vs. vertical height (Correct answer)
- Engine brand preference
- Track width specification
Correct answer: Whether the work requires horizontal reach vs. vertical height
Long-reach excavators extend horizontal working radius, while high-reach machines provide vertical working height for tall structure demolition.
Question 7: Which OSHA standard most directly governs powered industrial truck (forklift) operation on demolition sites?
- 29 CFR 1926.650
- 29 CFR 1910.178 (Correct answer)
- 29 CFR 1926.1400
- 29 CFR 1910.147
Correct answer: 29 CFR 1910.178
29 CFR 1910.178 governs powered industrial trucks including forklifts, covering operator training, inspections, and load handling.
CDS Equipment Selection & Operations 3
During high-reach demolition, what is the maximum recommended working height relative to the equipment's rated reach to prevent tip-over?