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ASTM B979-2018 pdf free download

ASTM B979-2018 pdf free download.Standard Specification for Non-Specular (NS) Surface Finish on Overhead Aluminum Electrical Conductors
1. Scope
1.1 This specification covers non-specular surface finishes on overhead aluminum electrical conductors. Overhead alumi- num electrical conductors, when installed, typically have a shiny surface appearance. This “reflective” or “specular” surface can make a transmission line more noticeable in appearance against the background landscape. A factory treat- ment process of the outer surface of the aluminum wires can render the surface finish into a dull, non-reflective, matte grey finish. This non-reflective or “de-glared” surface finish allows the conductor to become less visible when observed from a distance and enables the transmission line to blend in with the skyline or landscape background. 2 1.2 This specification is intended, by means of diffuse reflectance measurement, to establish a uniformity of conduc- tor finish which is acceptable to the user. Such a specification will furnish a basis for consistent manufacturing process control. 1.3 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appro- priate safety, health, and environmental practices and deter- mine the applicability ofregulatory limitations prior to use. 1.5 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
4. Ordering Information
4.1 Orders for material under this specification shall include the following information: 4.1.1 Aluminum overhead electrical conductor to have a non-specular, Type “NS” surface finish. 4.1.2 Unless otherwise specified the default non-specular gray finish requirement shall have an average maximum diffuse reflectivity of not more than 32 %.
5. Equipment
5.1 To measure diffuse reflectance, a portable reflectance meter 4 shall be employed with search units “Y” or “T,” equipped with a green tristimulus filter.
6. Test Procedure
6.1 Four test measurements shall be made on every 1 000 000 ft (305 000 m) or fraction thereof produced per order, per conductor size, with no more than one measurement per reel. Test measurements may be made either on the conductor during processing or on samples approximately 15 in. (380 mm) long removed from the reel. Care must be taken to minimize surface marks and loose stranding due to sample handling. Samples should be free of any foreign materials such as oil, grease, dirt, and metal particles. 6.2 A 13 ⁄ 16 in. (0.8125 in./20.64 mm) diameter aperture should be used for measuring 397 500 cmil (200 mm 2 ) area conductors and larger. For smaller conductor, a 1 ⁄ 4 in. (0.25 in./6.35 mm), or 3 ⁄ 8 in. (0.375 in./9.52 mm) aperture should be used. 6.3 Prior to each diffuse reflectance measurement, the mea- suring instrument shall be calibrated against a matte gray reference standard having a diffuse reflection value between 23 and 29 %. The instrument is to be checked against the reference standard before and after each series of readings to ensure reliability and reproducibility of results (see Explana- tory Note 1). Caution should be exercised that the search unit is not pointed towards brightly lighted areas during measure- ments. 6.4 To allow for slight variations in conductor surface color and contour, a minimum of three areas of the sample shall be evaluated. The maximum reflectance for each area is deter- mined by placing the conductor’s surface centered over the aperture of the measuring device and moving the sample longitudinally back and forth to obtain the maximum reading. The average of the three maximum readings so obtained constitutes the acceptance criterion for diffuse reflectivity of the sample.

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