Roof Sailing Rigging and Line Systems 1 — Questions and Answers
Question 1: Which knot is most commonly used to secure a lifeline to a fixed anchor point on a roof?
- Bowline (Correct answer)
- Reef knot
- Slip knot
- Overhand knot
Correct answer: Bowline
The bowline creates a fixed loop that will not slip or tighten under load, making it the standard knot for securing lifelines to anchor points.
Question 2: What is the minimum working load limit (WLL) rating required for a personal fall arrest anchor point under OSHA standards?
- 5,000 lbs per worker attached (Correct answer)
- 2,500 lbs per worker attached
- 1,000 lbs per worker attached
- 3,000 lbs per worker attached
Correct answer: 5,000 lbs per worker attached
OSHA 1926.502 requires that anchor points for personal fall arrest systems be capable of supporting at least 5,000 lbs per worker attached.
Question 3: Which type of rope is preferred for roof rigging systems due to its high strength-to-weight ratio and low stretch characteristics?
- Kernmantle static rope (Correct answer)
- Manila fiber rope
- Twisted nylon rope
- Polypropylene rope
Correct answer: Kernmantle static rope
Kernmantle static rope has a braided core (kern) protected by a woven sheath (mantle), providing high strength, low elongation, and excellent abrasion resistance for rigging.
Question 4: When inspecting a rope for continued use, which defect would require immediate removal from service?
- Core damage visible through the sheath (Correct answer)
- Slight surface abrasion on the sheath
- Mild stiffness from cold temperatures
- Minor dirt embedded in the outer fibers
Correct answer: Core damage visible through the sheath
Any damage to the rope's core visible through the sheath means the primary load-bearing structure is compromised, and the rope must be retired immediately.
Question 5: A prusik hitch is used in roof rigging systems primarily for which purpose?
- As a friction hitch that grips under load but slides when unweighted (Correct answer)
- As a permanent anchor knot at the ridge
- To join two ropes of equal diameter
- To prevent a rope from fraying at cut ends
Correct answer: As a friction hitch that grips under load but slides when unweighted
A prusik hitch is a friction hitch that locks onto the rope when loaded (as in a fall) but can be slid along the rope when unweighted, making it useful for ascent/descent and positioning.
Question 6: What is the purpose of a rope grab device in a horizontal lifeline system on a roof?
- To allow a worker to move along the line while automatically arresting a fall (Correct answer)
- To permanently fix the lifeline to an anchor
- To reduce the rope's overall tension during use
- To splice two lifeline sections together
Correct answer: To allow a worker to move along the line while automatically arresting a fall
A rope grab slides freely along a horizontal lifeline as the worker moves but instantly locks onto the line if a fall begins, limiting fall distance.
Question 7: When setting up a rigging system on a sloped roof, the anchor line should be positioned at what minimum angle relative to the roof surface?
- As close to perpendicular (90°) to the slope as practical (Correct answer)
- Parallel to the roof slope
- At a 45° angle downslope
- At a 30° angle upslope
Correct answer: As close to perpendicular (90°) to the slope as practical
Anchoring perpendicular to the slope maximizes the holding strength of the anchor and minimizes the pendulum effect if a fall occurs.
Roof Sailing Rigging and Line Systems 1
Which knot is most commonly used to secure a lifeline to a fixed anchor point on a roof?