UL-6:2010 pdf free download – Electrical Rigid Metal Conduit 一Steel.
6.2.1.4 The supplementary coating described in Clause 5.3.5 need not comply with Clause 6.2.1.1.
6.2.1.5 For identification of compounds, a nonmetallic material used as an alternate corrosion-resistant or organic coating shall be subjected to the infrared spectroscopy (IR), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) tests specified in the applicable standards for polymeric materials. See Reference Item No. 7, Annex A.
6.2.2 Zinc coating
6.2.2.1 A solution of copper sulfate for this test shall be made from distilled water and a reagent grade of cupric sulfate (CuSO4). In a copper container or in a glass, polyethylene, or other chemically nonreactive container in which a bright piece of copper is present, a quantity of cupric sulfate shall be dissolved in hot distilled water. The purpose is to obtain a solution that has a specific gravity slightly higher than 1.186 after the solution is cooled to a temperature of 18.3°C (65.0°F). Any free acid that might be present shall be neutralized by the addition of approximately 1 gram of cupric oxide (CuO) or 1 gram of cupric hydroxide (Cu(OH)2) per liter of solution. The solution shall then be diluted with distilled water to obtain a specific gravity of exactly 1.186 at a temperature of 18.3°C (65.0°F). The solution shall then be filtered.
6.2.2.2 Several 150-mm (6-in) specimens shall be cut from a sample length of the finished zinc-coated conduit. With prudent attention to the risks to health and to the risk of fire, the specimens shall be cleaned with a suitable organic solvent. Each specimen shall then be examined for evidence of damage to the zinc coating, and only specimens that are not damaged shall be selected for use in the test. When a zinc coating is used on the inside and outside of the conduit, half of the specimens shall be longitudinally cut in half to expose the inside surface. If a zinc coating is used only on the outside of the conduit, none of the specimens shall be cut longitudinally.
6.2.2.3 The selected specimens shall be rinsed in water, and all surfaces shall be dried with clean cheesecloth. As much of the water as possible shall be removed in the drying operation because water slows the reaction between the zinc and the solution, thereby adversely affecting the test results. The surface of the zinc shall be dry and clean before a specimen is immersed in the solution of copper sulfate. The specimens shall not be touched by the hands or anything else that can contaminate or damage the surfaces.
6.2.2.4 A glass, polyethylene, or other chemically nonreactive beaker having a diameter equal to approximately twice the diameter measured over the specimen shall be filled with the solution of copper sulfate to a depth of not less than 76 mm (3 in). The temperature of the solution shall be maintained at 18.3 ±1.1°C (65.0 ±2.0°F). The specimen shall be immersed in the solution and supported on end in the center of the beaker so that not less than 64 mm (2-1/2 in) of its length is immersed. The specimen shall remain in the solution for 60 s, during which time it shall not be moved nor shall the solution be stirred.
6.2.2.5 At the end of the 60 s period, the specimen shall be removed from the beaker, rinsed immediately in running tap water, rubbed with clean cheesecloth until any loosely adhering deposits of copper are removed, and shall then be dried with clean cheesecloth. Again, the hands and other damaging and contaminating objects and substances shall not touch the surfaces that were immersed. The part of the specimen that was immersed shall be examined, considering each broad surface separately and disregarding any threaded area and the portions of the specimen within 13 mm (1/2 in) of the cut ends on sizes 12 — 53 (3/8 — 2) and 25 mm (1 in) for sizes 63 — 155 (2-1/2 — 6) and within 3 mm (1/8 in) of any longitudinal edges cut in the process of preparing the specimen.