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ASTM E574-2019 pdf free download

ASTM E574-2019 pdf free download.Standard Specification for Duplex, Base Metal Thermocouple Wire With Glass Fiber or Silica Fiber Insulation
1. Scope
1.1 This specification sets forth the requirements for duplex, types E, J, K, N and T thermocouple wire, insulated with E-glass, S-glass, amorphous silica fiber or polycrystalline fiber. 1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only. 1.3 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. 1.4 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.
3. Terminology
3.1 Definitions—The definitions given in Terminology E344 shall apply to this standard. 3.2 Definitions ofTerms Specific to This Standard: 3.2.1 amorphous silica fiber, n—continuous filament of heat-insulating material whose principal constituent is amor- phous silica. 3.2.2 duplex wire, n—matched pair of parallel, solid thermoelements, individually insulated (double wrap or braid) with insulating fibers and a fiber braid of the same material overall. 3.2.3 E-glass, n—family of calcia-alumina-silicate glasses that are used for general purposes and most electrical applica- tions. 3.2.4 impregnate, v—to saturate the fiber insulation of wires with a high-temperature electrical insulating compound to form a moisture barrier around the wires and to inhibit fraying ofthe fibers. 3.2.5 polycrystalline fiber, n—continuous polycrystalline filament of heat-insulating material whose composition is alumina, boria, and silica in an approximate ratio of 3:1:2, respectively. 3.2.6 S-glass, n—family of magnesia-alumina-silicate glasses with a higher tensile strength and higher softening temperature than E-glass.
4. Significance and Use
4.1 This specification presents the requirements for impreg- nated and non-impregnated fiber-insulated thermocouple wire for normally accepted industrial use, but does not attempt to define such usage. 4.2 A supplement contains the requirements for insulated thermocouple wire that will be exposed to high humidity. The purchase order or inquiry shall specify if the requirements in this supplement are required.
7. Technical Requirements
7.1 Insulated Thermocouple Wire: 7.1.1 Materials—Thermoelements shall be solid thermo- couple grade materials with a smooth, bright finish (Note 4) and shall be fully annealed prior to insulating. N OTE 4—An optional copper-flash coating on the iron thermoelement for type J thermocouple material is permitted to prevent rusting. This coating must be applied uniformly so that the final calibration tolerance requirement for the specific insulating material is still met. 7.1.2 Sizes—Thermoelements shall be specified in Ameri- can Wire Gauge (AWG) nomenclature. Corresponding thermo- element diameters shall be as listed in Table 1. 7.1.3 Calibration: Standard Method—When required by the purchase order, calibration of the insulated thermocouple wire shall be performed by one of the procedures described in Test Method E207 or E220. Thermoelement Initial Calibration Tolerances —Standard and special tolerances on initial values of emf versus temperature are given in Table 1 of Specification E230/E230M. The purchase order shall specify whether stan- dard or special tolerances are required. 7.2 Insulation Materials: 7.2.1 Individual thermoelements shall be covered with a braid, or double wrap (one wrap in each direction) of glass fibers (Classes A and E), a braid of glass fibers (Classes B and F), or braid of fibers (Classes C and D). 7.2.2 The outer covering shall consist of a braid of the same material applied over the bare thermoelements. 7.2.3 For Classes A and E duplex thermoelements, the insulation on the individual thermoelements and the outer braid shall be impregnated with a moisture and heat-resistant elec- trical insulating compound. The fibers shall be bonded suffi- ciently to each other to prevent fraying under normal condi- tions of installation and service. 7.2.4 Each individual Class A and E thermoelement wrap or braid and the outer braid shall be color-coded in accordance with Specification E230/E230M.

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