ASTM C871-2018 pdf free download
ASTM C871-2018 pdf free download.Standard Test Methods for Chemical Analysis of Thermal Insulation Materials for Leachable Chloride, Fluoride, Silicate, and Sodium Ions
1. Scope
1.1 These test methods cover laboratory procedures for the determination of water-leachable chloride, fluoride, silicate, and sodium ions in thermal insulation materials in the parts per million range. 1.2 Selection ofone ofthe test methods listed for each ofthe ionic determinations required shall be made on the basis of laboratory capability and availability ofthe required equipment and appropriateness to the concentration of the ion and any possible ion interferences in the extraction solution. 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.
5. Significance and Use
5.1 Research has demonstrated that in addition to the halide ion chloride; fluoride ions, when deposited and concentrated on the surface of austenitic stainless steel, can contribute to external stress corrosion cracking (ESCC) in the absence of inhibiting ions. 5 Two widely used insulation specifications that are specific to ESCC allow the use of the same Test Methods C692 and C871 for evaluation of insulation materials. Both specifications require fluoride ions to be included with chloride ions when evaluating the extractable ions. 5.2 Chlorides (and fluorides) can be constituents of the insulating material or of the environment, or both. Moisture in the insulation or from the environment can cause chlorides (and fluorides) to migrate through the insulation and concen- trate at the hot stainless steel surface. 5.3 The presence of sodium and silicate ions in the insula- tion has been found to inhibit external stress corrosion cracking caused by chloride (and fluoride) ions, whether such ions come from the insulation itself or from external sources. Furthermore, if the ratio of sodium and silicate ions to chloride (and fluoride) ions is in a certain proportion in the insulation, external stress corrosion cracking as a result of the presence of chloride (and fluoride) in the insulation will be prevented or at least mitigated (see also Specification C795).
8. Test Specimen
8.1 Apparatus and tools used for special preparation and leaching shall be clean and free of chlorides, fluorides, silicates, sodium, and acidic or alkaline materials that might affect the chemical test. Distilled water must be used in all tests unless deionized water has been shown to be adequate. 8.1.1 For molded insulation, use a band saw or equivalent, making several cuts through the entire cross section of each piece of insulation to be tested. Each specimen shall be representative of the entire cross section of the piece, except that metal screen, or expanded metal used as a supportive facing shall not be included. It is recommended that thin wafers of material be cut between 1 ⁄ 16 and 1 ⁄ 8 in. (1.6 and 3.2 mm) thick. Cut enough material for two 20-g samples. 8.1.2 Blanket fibrous materials are cut into strips across the entire width of the blanket using clean, dry scissors. 8.1.3 Samples containing moisture are placed in a suitable container, protected from contamination, and oven dried at 230 6 10°F (100 6 5°C) ( or manufacturers recommended temperature) to a constant weight (60.1 g) or overnight.
