Non-Specular (NS) Surface Finish on Overhead Aluminum Electrical Conductors

B979-12: Standard Specification for Non-Specular (NS) Surface Finish on Overhead Aluminum Electrical Conductors

Ensuring the visual integration of vast electrical transmission infrastructure with the natural landscape is a critical design consideration. ASTM B979-12 provides an essential, industry-leading standard for achieving a non-specular surface finish on overhead aluminum electrical conductors, directly addressing concerns about visual impact and aesthetic blending. This comprehensive specification offers proven methods for manufacturers and engineers to control and verify conductor appearance.

What is B979-12?

ASTM B979-12, "Standard Specification for Non-Specular (NS) Surface Finish on Overhead Aluminum Electrical Conductors," establishes criteria for manufacturing aluminum conductors with a dull, matte gray surface. Originating from industry efforts to minimize the visual prominence of transmission lines, its primary purpose is to define a non-reflective finish that allows conductors to blend more effectively with their surroundings, thereby enhancing environmental aesthetics.

Scope & Purpose

This standard governs the manufacturing process and testing requirements for achieving a non-specular (NS) surface finish on overhead aluminum electrical conductors. It specifically addresses the control of diffuse reflectance to ensure a consistent, matte appearance. The scope includes specifying measurement techniques and acceptable limits for reflectivity, while it does not cover the conductor's electrical performance or structural integrity, which are addressed by other standards.

Who Must Comply?

• • Primary audience: Electrical Engineers, Materials Engineers, Quality Control Inspectors, and Manufacturing Supervisors involved in the production or specification of overhead aluminum conductors.
• • Industries affected: Electrical Power Transmission, Aluminum Manufacturing, and Conductor Manufacturing.
• • Compliance nature: Voluntary, but often specified by utility companies and transmission line developers for aesthetic reasons.
• • Enforcement: Primarily through contractual agreements and quality assurance testing by manufacturers and end-users.

Key Requirements Overview

The standard requires manufacturers to implement processes that produce a dull, non-shiny surface on aluminum conductors. Professionals must ensure that the diffuse reflectance of the conductor's outer surface is measured using calibrated equipment and specific test procedures. Key provisions include:

• • Defining a non-specular (matte, non-shiny) finish for overhead aluminum electrical conductors.
• • Establishing a maximum allowable average diffuse reflectivity, typically not exceeding 32%, to achieve the desired visual effect.
• • Mandating specific test procedures, including the use of a portable reflectance meter with a green tristimulus filter and proper calibration against a reference standard.
• • Outlining sampling and testing frequencies to ensure consistent quality across production batches.
• • Providing retesting criteria to address any initial non-conforming results, ensuring product reliability.

Related Standards & References

ASTM B979-12 works in conjunction with other essential standards. ASTM B354, "Standard Terminology Relating to Uninsulated Metallic Electrical Conductors," provides foundational definitions for conductor-related terms. While not directly referenced in the provided extract, other ASTM standards detailing the mechanical and electrical properties of overhead aluminum conductors would be critical for a complete conductor specification, ensuring that the non-specular finish does not compromise performance.