ANSI SCTE 251-2018 pdf download.Test Procedure for Determining the Thermal Oxidative Stability of Foamed Polyethylene
1.2. Scope
This method covers the determination of an Oxidative Induction Time (OIT) value for coaxial cable, foamed polyethylene, and insulation materials removed from completed cable products. This test procedure is based on the ASTM D4565. The OIT value is determined by a thermo-analytical measurement of the onset time for the exothermic oxidation of insulation in pure oxygen, at a specified temperature.
1.3. Benefits
This document is designed to benefit manufacturers and end users of product tested to this procedure by supplying a standardized method for determining an Oxidative Induction Time (OIT) value for coaxial cable, foamed polyethylene, and insulation materials removed from completed cable products.
1.4. Intended Audience
This document is intended for anyone desiring to make industry standard OIT measurements of coaxial cable, or for anyone acquiring product purported to have been tested using this method.
1.5. Areas for Further Investigation or to be Added in Future Versions None.
2. Normative References
The following documents contain provisions, which, through reference in this text, constitute provisions of this document. At the time of Subcommittee approval, the editions indicated were valid. All documents are subject to revision; and while parties to any agreement based on this document are encouraged to investigate the possibility of applying the most recent editions of the documents listed below, they are reminded that newer editions of those documents might not be compatible with the referenced version.
4. Compliance Notation
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Discussion—Other components in the foam material may cause secondary effects. The OIT value for insulation may be significantly altered by contamination or additives such as pigments, fillers, and processing aids as well as catalyst residues from the cable, wire, insulation, or resin manufacture. The OIT value may increase or decrease depending on whether these additives and residues act as oxidation inhibitors or promoters at the test temperature. At typical test temperatures (for example, ANSI/SCTE 74 requires 180 °C), compounds present in the polyolefin material may decompose and change the polyolefin oxidation mechanism and thereby the OIT value. If the oxidation mechanism is so altered, then the OIT value may not correlate to aging at normal use temperatures. Before using the OIT value to predict field performance and lifetimes, additional studies may be required to establish a correlation between the OIT value measured at high temperature and the performance of the polyolefin under typical field conditions. The OIT value is useful as a product performance test and quality control parameter, or a research and development tool for polyolefin materials.ANSI SCTE 251-2018 pdf download
