ISA Arborist Safety and Standards Questions and Answers 1 — Questions and Answers
Question 1: An arborist must prune branches from a tree canopy that is growing within the minimum approach distance of a 7,200-volt primary distribution line. According to ANSI Z133 standards, what is the closest a *qualified* line-clearance arborist is permitted to approach this conductor?
- 2 feet, 2 inches (Correct answer)
- 10 feet, 0 inches
- 1 foot, 7 inches
- As close as necessary with insulated tools
Correct answer: 2 feet, 2 inches
According to the ANSI Z133 standard, the minimum approach distance (MAD) for qualified line-clearance arborists working near energized conductors from 1.1 to 15.0 kilovolts (kV) is 2 feet, 2 inches. The general '10-foot rule' applies to unqualified persons.
Question 2: According to ANSI Z133 safety standards, which of the following is a prohibited practice when starting a chainsaw on a work site?
- Starting the saw on level ground with a foot securing the rear handle.
- Using the leg-lock method with the saw handle placed between the thighs.
- Drop-starting the saw by holding it in one hand and pulling the starter cord with the other. (Correct answer)
- Engaging the chain brake before pulling the starter cord.
Correct answer: Drop-starting the saw by holding it in one hand and pulling the starter cord with the other.
ANSI Z133 explicitly prohibits drop-starting a chainsaw. This method does not provide adequate control of the saw during the high-torque action of starting, creating a significant risk of injury. Safe methods involve stabilizing the saw on the ground or firmly between the legs.
Question 3: A tree care crew is preparing for the day's work, which includes one climber and two ground workers. According to ANSI Z133, what is the minimum requirement for emergency readiness on this crew?
- All three crew members must be certified in first aid and CPR.
- At least one worker on site must be trained in aerial rescue procedures. (Correct answer)
- The company must have a written emergency plan for every tree being worked on.
- The job site must be within a 15-minute response time of a hospital.
Correct answer: At least one worker on site must be trained in aerial rescue procedures.
ANSI Z133 requires that workers be trained in emergency procedures, including aerial rescue. While having multiple people trained in first aid/CPR is best practice, the standard's critical provision for climbing operations is ensuring that someone on site has the specific training to rescue an injured or incapacitated worker from aloft.
Question 4: Which of the following best describes the primary hazard associated with "negative blocking" or "negative rigging" during tree removal operations?
- It causes excessive friction and heat buildup on the rigging rope.
- It generates significant shock loading and dynamic forces on the rigging system. (Correct answer)
- It requires a complex knot system that is difficult for ground workers to manage.
- It is only effective for removing small-diameter, lightweight limbs.
Correct answer: It generates significant shock loading and dynamic forces on the rigging system.
Negative rigging, where a cut piece is allowed to fall before being caught by the rigging line, creates a shock load. The resulting dynamic forces can be many times greater than the static weight of the wood, potentially causing catastrophic failure of the rigging equipment or the anchor point in the tree.
Question 5: An arborist is setting their climbing line using a moving rope system (MRS) with a friction hitch. Before leaving the ground, what is the most critical safety check that must be performed on the climbing system?
- Ensuring all carabiners are made of steel for maximum strength.
- Verifying the climbing line has a diameter of exactly 1/2 inch (13mm).
- Measuring the length of the friction cord to ensure it matches the rope diameter.
- Testing the hitch to confirm it grips the rope securely and releases when intended. (Correct answer)
Correct answer: Testing the hitch to confirm it grips the rope securely and releases when intended.
Before an arborist's weight is committed to the climbing system, the friction hitch must be tested to ensure it functions correctly. This involves making sure it will grab the rope to hold the climber's weight, but also release smoothly for controlled movement. This function check is paramount to preventing an uncontrolled ascent or descent.
Question 6: Which set of Personal Protective Equipment (PPE) is required by ANSI Z133 for a ground worker operating a chainsaw?
- Hard hat and steel-toed boots only.
- Hearing protection, eye protection, and gloves.
- A high-visibility vest and work boots.
- Head protection, eye protection, hearing protection, and cut-resistant leg protection. (Correct answer)
Correct answer: Head protection, eye protection, hearing protection, and cut-resistant leg protection.
ANSI Z133 mandates a comprehensive set of PPE for ground-based chainsaw operations. This includes a hard hat (head protection), eye protection, hearing protection, and cut-resistant leg protection (chaps or chainsaw pants) to protect against the most common and severe hazards associated with the task.
ISA Arborist Safety and Standards Questions and Answers 1
An arborist must prune branches from a tree canopy that is growing within the minimum approach distance of a 7,200-volt primary distribution line.
According to ANSI Z133 standards, what is the closest a *qualified* line-clearance arborist is permitted to approach this conductor?