In this article, we will look at pending revisions to the ANSI Z133 Standard for Arboricultural Operations – Safety Requirements (ANSI Z133-2017), Section 4 – Electrical Hazards.
I had the pleasure of speaking at TCI EXPO ’21 in Indianapolis, Indiana, about the work being done at the time on Section 4 – Electrical Hazards for the upcoming revision. The Z was last published in 2017 and is scheduled to be revised every five years. At the time of the EXPO presentation, much of Section 4 was still being formalized by the task group. I was speaking on work that was not yet completed, so I provided the audience with a 30,000-foot view of what we were working on. Since the presentation, much of the original framework that was presented remains. However, final approval from the Z133 Committee is still pending.
The crux of the changes in Section 4 focus on the following five main topics:
- Radiofrequency (RF) safety.
- Level 1 Arborist – Electrically Unqualified.
- Level 2 Arborist – Electrically Qualified (formerly Incidental Line Clearance).
- Level 3 Arborist – Qualified Line Clearance.
Electrical hazards training
The focus here is that all arborists are to receive training in electrical hazards. More specifically, the employer shall ensure that the arborists’ training and degree of training in electrical hazards are determined by the risk to the employee for the hazard(s) involved.
Radiofrequency (RF) safety
The Z133 Committee tasked the Electrical Hazard task group with creating awareness of radiofrequency safety, as RF antennas are becoming more prevalent in our work environment. This new section aims to bring RF hazard awareness to arborists and to require the employer to provide training in RF hazards.
The task group’s biggest challenge was reworking subsections 4.2 and 4.3, which involve who is qualified to work around electrical supply lines. As a result, the task group created the following three levels of arborists.
Level 1 Arborist: Electrically Unqualified. These arborists are considered electrically unqualified. While they have received electrical-hazards-awareness training, they have not received sufficient training. Nor have they demonstrated proficiency in skills and techniques necessary to qualify for a Level 2 or 3 Arborist. Level 1 Arborists shall maintain minimum approach distances (MADs) shown in Table 1 in the Z133 standard.
Level 2 Arborist: Electrically Qualified. Formerly the “Incidental Line Clearance” classification, these arborists perform tree work where an electrical hazard exists to the arborist, but the hazard is incidental to the work. The arborist is not working for the purpose of clearing space around the electric supply lines on behalf of the utility that controls or operates the wires/lines. The Electrically Qualified Arborist, through related education and on-the-job training, is familiar with the equipment and hazards they may be exposed to in incidental line clearance. They also have demonstrated the ability to perform the special techniques involved at either low or primary voltages. The Electrically Qualified Arborist is broken into two categories: Low Voltage Level 2 and Primary Voltage Level 2.
Level 2 Arborist – Low Voltage Electrically Qualified (750V and less). These workers are trained and competent to perform arboricultural work within 10 feet of 750 volts and less, but not closer than distances shown in Table 2.1. This Level 2 Arborist may enter a tree and perform work within the tree, but may not bring their body nor conductive material within 10 feet of the primary electric supply line in excess of 750V.
Level 2 Arborist – Primary Voltage Electrically Qualified. This arborist is trained and competent to perform arboricultural work within 10 feet of 35 kilovolts (kV) and less, but not closer than distances shown in Table 2.2. The Primary Voltage Level 2 Qualified Arborist may enter a tree and perform work within the tree. But they may not bring their body nor conductive material within 10 feet of the primary electric supply line in excess of 35kV.
Level 3 Arborist – Qualified Line Clearance. Lastly, this is an arborist who, through related training and on-the-job experience, is familiar with the equipment and hazards in line clearance, has demonstrated the ability to perform the special techniques involved and is working on behalf of the host employer (a utility). The Level 3 Arborist shall maintain MAD from energized electrical conductors in accordance with Table 3 in the Z133.
As it stands, Section 4 focuses on the training of arborists in regard to electrical hazards and their potential exposure to those hazards. The second objective is to clear up misunderstandings and grey areas in the current Z133 that led to confusion.
Disclaimer: Revisions to Section 4 – Electrical Hazards have not yet been approved by the Accredited Standards Committee, ANSI Z133. This article is not intended to be an interpretation of the standard in any way, but merely an overview of some proposed changes.
Hollis (Les) W. Day, CTSP, ISA Utility Arborist, is safety director/new business development with Mountain F. Enterprises, Inc. (MFE), a 14-year TCIA member company based in Folsom, California.
This article was based on his presentation on the same subject during TCI EXPO ’21 in Indianapolis, Ind. To listen to an audio recording for that presentation, go to this page in the digital version of this issue of TCI Magazine online at tcimag.tcia.org and, under the Resources tab, click Audio. Or, under the Current Issue tab, click View Digimag, then go to this page and click here.
Would like to have a clear definition of
-demonstrated proficiency in skills and techniques necessary to qualify?
-education and on-the-job training, ?
-demonstrated the ability to perform the special techniques?
Great article thank you .