March 29, 2012
Walter B. Tucker Jr., CSP, CHST
President, Nutmeg Chapter
American Society of Safety Engineers
10 Larkspur Lane
Hamden, CT 06514-2615
Dear Mr. Tucker:
Thank you for your October 29, 2010 letter to the Occupational Safety and Health Administration. Because your inquiry involves construction issues, it was forwarded to the Directorate of Construction for response. I apologize for the delay in our reply. You ask for clarification of the requirement in 29 CFR §1926.1408(a)(1) for identifying the "work zone" when a crane works near a power line. This letter constitutes OSHA's interpretation of only the requirements discussed and may not be applicable to any question not delineated in your original correspondence.
The first scenario you describe is illustrated in the following drawing (Example 1) attached to your letter.
A crane with a telescopic boom is positioned between a flatbed truck and a building. It will be used to lift a HVAC unit from the flatbed to the roof of the building. Power lines are located on the side of the flatbed opposite the crane. The employer has demarcated the work zone with three flags located in a straight line that cuts across the dotted circle with the crane at its center. The radius of the circle represents the extension of the boom at its maximum extension and at the minimum angle shown in the crane's load chart for the weight and shape of the load to be picked. However, a circle drawn at the maximum radius the boom could reach would have a larger radius. The three flags form a line (the demarcated boundary line) parallel to the power line that is located at a distance from the power line equal to the minimum clearance distance required by the standard.
Question 1: Assuming that the flags are clearly visible to the crane operator, would demarcating the work zone as shown in Example 1 achieve compliance with the standard?
Response 1: Yes, as long as (1) the crane operator is prohibited from operating the crane outside the line of flags used to demarcate the work zone, and (2) the flags are close enough to each other and extend far enough along the demarcated boundary line that the operator is able to use them to judge whether the equipment remains within the demarcated boundary line.
The work zone requirement is found in §1926.1408(a), which provides:
§1926.1408 Power line safety (up to 350 kV) - equipment operations.
(a) Hazard assessments and precautions inside the work zone. Before beginning equipment operations, the employer must:
(1) Identify the work zone by either:
(i) Demarcating boundaries (such as with flags, or a device such as a range limit device or range control warning device) and prohibiting the operator from operating the equipment past those boundaries, or
(ii) Defining the work zone as the area 360 degrees around the equipment, up to the equipment's maximum working radius.
(2) Determine if any part of the equipment, load line or load (including rigging and lifting accessories), if operated up to the equipment's maximum working radius in the work zone, could get closer than 20 feet to a power line. If so, the employer must meet the requirements in Option (1), Option (2), or Option (3) of this section ...
In Example 1, the employer has demarcated the work zone under the §1408(a)(1)(i) option. The flags form a straight line that is parallel to the power line and give the operator a visual indication of whether the equipment, including the load, remains the minimum clearance distance from the power line. This type of demarcation - a line of flags parallel to the power line and located at least the minimum clearance distance from the power line - is one type of demarcation that is adequate under the standard. However, the number of flags must be sufficient to enable the operator to determine visually that the equipment remains the minimum clearance distance from the power line. If the spacing between the flags is too large or if the flags do not extend far enough along the demarcated boundary line, the operator may not be able to make that determination accurately.
When the work zone is demarcated under §1408(a)(1)(i), the employer must then determine, pursuant to §1408(a)(2), whether any part of the equipment, load line or load (including rigging and lifting accessories), could get closer than the minimum clearance distance to a power line. As OSHA stated in the preamble to the rule, "[t]his determination must be made based upon the assumption that the crane would be operated up to its maximum working radius (or, if a demarcated boundary is used, the assessment must be made with the assumption that the crane would be operated up to that boundary)." 75 FR 47952 (Emphasis added). If the demarcated boundary line is located at least the minimum clearance distance from the power line, the operator understands that no part of the equipment or load may go past the demarcated boundary line of flags, and the operator is able to judge the position of the equipment with respect to the demarcated boundary line, §1408(a)(2) is satisfied and no further precautions are needed.
Question 2: In Example 1a, the employer has demarcated the work zone by placing flags around the entire circle. Is it necessary to demarcate the work zone with flags around the entire circle, as shown in Example 1a?
Response 2: No. As discussed in Response 1, a line of flags parallel to the power line and at least the minimum clearance distance from the line will be sufficient as long as the operator understands that no part of the equipment or load may go past the line of flags and the operator is able to judge the position of the equipment with respect to the line of flags.
In the second scenario, the crane is between the flatbed and the power line. If the crane's boom is pointed in the direction of the power line at its maximum extension, it would be closer to the line than is permissible. Examples 2 and 2a show two possible arrangements of flags used to demarcate the work area.
Question 3: In Example 2, the operator is prohibited from swinging the boom past either of the two flags so that the boom, even at its maximum extension, remains in an arc that will keep it the minimum clearance distance from the power line. Is this sufficient to establish a work zone that will keep the crane at the minimum clearance distance, or are the additional flags shown in Example 2a also needed?
Response 3: The two flags shown in Example 2 are sufficient as long as the operator understands their purpose.
As stated in the preamble to the standard, one way a work zone can be defined is by demarcating boundaries "[t]o the left and right of the operator, to limit the lateral movement of the boom." 75 FR 47952. The two flags in Example 2 demarcate the work zone to the left and right of the operator and enable the operator to limit the lateral movement of the boom so that it stays the minimum clearance distance from the power line. As long as the operator understands that the boom must not be swung to the left of the flag on the building or to the right of the other flag, the minimum clearance distance will be maintained, and the additional flags shown in Example 2a are not needed.
Thank you for your interest in occupational safety and health. We hope you find this information helpful. OSHA requirements are set by statute, standards, and regulations. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. This letter constitutes OSHA's interpretation of the requirements discussed. Note that our enforcement guidance may be affected by changes to OSHA rules. Also, from time to time we update our guidance in response to new information. To keep apprised of such developments, you can consult OSHA's website at http://www.osha.gov. If you have any further questions, please feel free to contact the Directorate of Construction at (202) 693-2020.
James G. Maddux, Director
Directorate of Construction