This document is ASTM D373 – 89 “Standard Specification for Black and Yellow Straight-cut and Bevel-cut Varnished Cloth and Tape for Electrical Insulation”

which provides detailed regulations on various aspects of varnished cloth and tape for electrical insulation. The main contents are as follows:
1. Obseg

Applicable to black and yellow straight-cut and bevel-cut varnished cloth and tape for electrical insulation, and the units are in English.
2. Reference: References to multiple ASTM standards such as D295, involving varnished cloth testing, paper tear resistance testing, insulating oil specifications, itd.
3. Informacije o naročanju: The material type, color, velikost, surface type, packaging method, number of rolls per package, and packaging identification, itd. must be specified.
4. Material and Manufacturing: The material and number of paint layers should meet the specifications; no more than one splicing per 100 yards (90 metrov) or shorter roll, no splicing for 6 yards (5 metrov) or shorter rolls; the product should be free of defects such as wrinkles, excessive particles, bubbles, itd.
5. Physical properties: The requirements for breaking strength and elongation of materials of different thicknesses and different cutting methods are specified; the oil-resistant paint film should not have blistering, decomposition, or peeling; the average transverse tear strength of the straight-cut product should not be less than 250g.
6. Dielectric breakdown: Including the dielectric breakdown requirements of stress-free (initial), 6% raztezek, and after hot oil treatment, and the uniformity indicators within the coil and between coils of the same batch must be met.
7. Dimensions and allowable deviation: The nominal values ​​and allowable deviations of thickness, širina, and length are specified.
8. Surface finish: Black varnished cloth has three surface types: greasy, dry, and sticky, while yellow varnished cloth has only two types: dry and sticky.
9. Vzorčenje: Based on the batch definition of D3636, sampling methods are specified for fabrics, tapes, and strips of different widths.
10. Preskusna metoda: The samples are processed and tested according to the D295 method, and the test pieces are marked for traceability.
11. Inspection and testing: Materials should be inspected and tested within 3 weeks of receipt.
12. Rejection and re-inspection: Materials may be rejected if they do not meet the packaging and marking requirements, or if a certain proportion of sample rolls do not meet the quality requirements; rejection requires written notification to the supplier and provision of test results. Both parties may jointly sample and re-inspect, and the costs shall be borne by the responsible party.
13. Packaging and packaging labeling: The purchaser shall specify whether the tape is dry-packed or oil-impregnated, and specify the packaging details and labeling requirements.