1、 Standard Test Method Durability Test for Copper/Copper Sulfate Permanent Reference Electrodes for Direct Burial Applications This NACE International standard represents a consensus of those individual members who have reviewed this document, its scope, and provisions. Its acceptance does not in any
2、 respect preclude anyone, whether he or she has adopted the standard or not, from manufacturing, marketing, purchasing, or using products, processes, or procedures not in conformance with this standard. Nothing contained in this NACE International standard is to be construed as granting any right, b
3、y implication or otherwise, to manufacture, sell, or use in connection with any method, apparatus, or product covered by Letters Patent, or as indemnifying or protecting anyone against liability for infringement of Letters Patent. This standard represents minimum requirements and should in no way be
4、 interpreted as a restriction on the use of better procedures or materials. Neither is this standard intended to apply in all cases relating to the subject. Unpredictable circumstances may negate the usefulness of this standard in specific instances. NACE International assumes no responsibility for
5、the interpretation or use of this standard by other parties and accepts responsibility for only those official NACE International interpretations issued by NACE International in accordance with its governing procedures and policies which preclude the issuance of interpretations by individual volunte
6、ers. Users of this NACE International standard are responsible for reviewing appropriate health, safety, environmental, and regulatory documents and for determining their applicability in relation to this standard prior to its use. This NACE International standard may not necessarily address all pot
7、ential health and safety problems or environmental hazards associated with the use of materials, equipment, and/or operations detailed or referred to within this standard. Users of this NACE International standard are also responsible for establishing appropriate health, safety, and environmental pr
8、otection practices, in consultation with appropriate regulatory authorities if necessary, to achieve compliance with any existing applicable regulatory requirements prior to the use of this standard. CAUTIONARY NOTICE: NACE International standards are subject to periodic review, and may be revised o
9、r withdrawn at any time in accordance with NACE technical committee procedures. NACE International requires that action be taken to reaffirm, revise, or withdraw this standard no later than five years from the date of initial publication and subsequently from the date of each reaffirmation or revisi
10、on. The user is cautioned to obtain the latest edition. Purchasers of NACE International standards may receive current information on all standards and other NACE International publications by contacting the NACE International FirstService Department, 1440 South Creek Dr., Houston, Texas 77084-4906
11、(telephone +1 281-228-6200). Approved 2011-06-24 NACE International 1440 South Creek Drive Houston, Texas 77084-4906 +1 281-228-6200 ISBN 1-57590-247-8 2011, NACE InternationalNACE Standard TM0211-2011 Item No. 21257 TM0211-2011 NACE International i _ Foreword Copper/copper sulfate (Cu/CuSO4) perman
12、ent reference electrodes(1) (PREs) have been used for many years to monitor buried structures susceptible to corrosive elements. These Cu/CuSO4PREs vary in both design and construction. They typically consist of pure copper in contact with an aqueous solution saturated with copper sulfate (CuSO4). T
13、his standard test method was developed to assess the relative durability provided by various Cu/CuSO4PRE designs. This standard is intended for PRE users to determine the relative durability of Cu/CuSO4PREs. The test method described in this standard may be used by PRE manufacturers for describing t
14、he performance of their Cu/CuSO4 PREs. The standard should be used by Cu/CuSO4 PRE users for specifying minimum acceptance criteria or for identifying products that may provide a longer service life. This standard was prepared by NACE Task Group (TG) 256, Electrodes, Field-Grade: Test Methods. TG 25
15、6 is administered by Specific Technology Group (STG) 62, Corrosion Monitoring and Measurement Science and Engineering Applications. It is also sponsored by STG 05, Cathodic/Anodic Protection,67*Oil and Gas Production Cathodic Protection, and STG 35, Pipelines, Tanks, and Well Casings. This standard
16、is issued by NACE International under the auspices of STG 62. In NACE standards, the terms shall, must, should, and may are used in accordance with the definitions of these terms in the NACE Publications Style Manual. The terms shall and must are used to state a requirement, and are considered manda
17、tory. The term should is used to state something good and is recommended, but is not considered mandatory. The term may is used to state something considered optional. _ (1) $OVRUHIHUUHGWRDVSHUPDQHQWUHIHUHQFHKDOI -FHOODQGLPSUHFLVHODVSHUPDQHQWUHIHUHQFHFHOOWKHVHUHIH UHQFHHOHFWURGHVKDYHILQLWHOLIHand co
18、uld more preciVHOEHFDOOHGSHUPDQHQWOLQVWDOOHG+RZHYHUWKLVVWDQGDUGXVHVWKHPRUHFRPPRQSHUPDQHQWUHIHUHQFHHOHFWURGH(PRE) nomenclature to describe these. TM0211-2011 ii NACE International _ NACE International Standard Test Method Durability Test for Copper/Copper Sulfate Permanent Reference Electrodes for Di
19、rect Burial Applications Contents 1. General .1 2. Test Equipment and Reagents 1 3. Test Procedure2 References 6 FIGURES Figure 1: Schematic of test apparatus for CuSO4leaching test .3 Figure 2: Schematic of test apparatus for chloride contamination test 4 _ TM0211-2011 NACE International 1 _ Sectio
20、n 1: General 1.1 This standard describes a test method to measure specific physical properties and the relative stability of Cu/CuSO4PREs when they are subjected to specific environmental stresses. These reference HOHFWURGHVZKLOHSHUPDQHQWLQWKHSKVLFDOVHQVH(they are not commonly removed), do exhibit a
21、 finite service life. This test method is intended to provide a measure of the relative durability that may be expected. The test method specifically focuses on the ability of the Cu/CuSO4PRE to (1) resist migration of CuSO4from within the PRE into its surrounding environment and (2) to resist the m
22、igration of chloride from its surrounding environment into the PRE. 1.2 Unique field conditions may alter the durability of Cu/CuSO4PREs. Factors such as temperature, sunlight, and soil contaminants can significantly affect PRE durability. Although consideration of these parameters is outside the sc
23、ope of this standard, they may require consideration in certain field applications. 1.3 Environmental factors must be accounted for while performing durability testing. Articles have been written indicating possible factors resulting in erroneous potential measurements from a half-cell and their rel
24、evance to PREs.1,2Variables that usually affect portable Cu/CuSO4reference electrodes are temperature and sunlight variations. Both cited articles indicate that potential measurements can vary by 0.9 mV/C (0.5 mV/F), and that exposure to direct sunlight can cause variations in potential up to +20 mV
25、. However, because PREs are typically used in locations with no direct sunlight exposure and limited temperature variations, such effects should be minimal.1Another environmental factor that can cause a change in potential is chloride contamination. This is generally only a problem with prolonged ex
26、posure to chloride-rich environments (e.g., seawater, brackish water, or chloride-rich soil). As the chloride contamination increases, the potential shifts further away from its reference potential (potential with no chlorides present) and can reach a value of 123 mV in a 60,000 ppm chloride solutio
27、n.2The chloride variations have been confirmed to some degree through laboratory testing.3All of these factors must be considered when Cu/CuSO4PRE durability tests are performed. 1.4 Long-term failure of PREs has been attributed to a dried-out PRE, which is a particular problem in dry soils. Consequ
28、ently, PREs are often installed prepotted in a moisture-retaining backfill. The tendency for PREs to dry out is not addressed by this test method. 1.5 The natural tendency for the potential of a Cu/CuSO4 PRE to vary must also be considered. Some of this variation may occur as a result of the age of
29、the PRE and/or differences in manufacturing. As a result, PREs are listed as being repeatable to r6 mV.4 1.6 The tests described herein are relative tests that should only be used to compare PREs that are tested concurrently. Users should not attempt to draw meaningful conclusions from the results o
30、f tests performed at different times because the variations may be the result of uncontrolled differences between the two tests rather than the differences in the PREs themselves. The tests are intended to provide comparative data on Cu/CuSO4PREs tested concurrently; therefore, no pass/fail criteria
31、 are established by this standard. 1.7 The tests described herein are relatively short in duration and there are insufficient data to show a correlation between proper short-duration tests and expected service life. However, it would be reasonable to conclude that if one PRE lasts longer than anothe
32、r in these tests, similar relative durability could be expected in actual applications. _ Section 2: Test Equipment and Reagents 2.1 High-LPSHGDQFHYROWPHWHURUGDWDORJJLQJGHYLFH DPLQLPXPLQSXWLPS HGDQFHRI0 XQOHVVLWFDQEHVKRZQWKDWDmeter with lower input impedance is sufficient) as required to ensure accu
33、rate measurements in a high-resistivity (deionized DI water) environment. The voltmeter shall have an accuracy of 2.0 mV or better in the range being measured; 2.2 DI water in accordance with ASTM(2)D1193,5Type IV (resistivity of 200,000 :cm); 2.3 A known Cu/CuSO4standard electrode; (2)ASTM Internat
34、ional (ASTM), 100 Barr Harbor Dr., West Conshohocken, PA 19428-2959. TM0211-2011 2 NACE International 2.3.1 A known accurate portable Cu/CuSO4reference electrode that has been properly rebuilt should be used. One way to determine accuracy is to measure several new or rehabilitated portable Cu/CuSO4r
35、eference electrodes against each other to confirm less than 5 mV deviation. 2.3.2 Alternatively, a Cu/CuSO4standard electrode may be constructed from appropriate materials including a pure copper plate in contact with a saturated CuSO4solution. Analytical-grade chemicals shall be used when construct
36、ing a standard electrode. The standard electrode shall be checked against a new or rehabilitated portable Cu/CuSO4reference electrode to confirm less than 5 mV deviation. 2.4 Reagent-grade sodium chloride (NaCl); 2.5 Temperature-monitoring device capable of reading 1 C (or 2 F) 2.6 Resistivity meter
37、 capable of reading the resistivity of 4,000 :cm water with a resolution of 1% of full scale. 2.7 Nonmetallic 19 L (5.0 gal) test containers; and 2.8 Nonmetallic tank of sufficient size to accommodate multiple test PREs for the chloride contamination test. A minimum of 10 L (2.5 gal) of solution sha
38、ll be used for each test PRE. _ Section 3: Test Procedure 3.1 The test procedure includes three elements: a visual examination, a CuSO4leaching test to determine the duration until significant CuSO4leaches from the test PRE, and a chloride contamination test to determine the duration until significa
39、nt chloride ions leach into the test PRE. 3.1.1 PREs shall be tested in the configuration in which they are used. Plastic bags or other shipping materials shall be removed prior to testing in accordance witKPDQXIDFWXUHUVLQVWUXFWLRQV 3.1.2 If a PRE is normally installed in a bag containing backfill,
40、it shall not be removed from the bag without consulting the manufacturer. Removing the PRE can affect its performance and, in some cases, permanently damage the PRE. 3.2 Visual Examination 3.2.1 A visual examination shall be performed on each test PRE. 3.2.2 The condition of the test PRE prior to te
41、sting shall be documented. 3.3 CuSO4 Leaching Test 3.3.1 Testing shall be performed to determine the relative performance of the test PRE when exposed to a standard environment that encourages the CuSO4solution to leach out of the test PRE. Figure 1 is a schematic of a representative test apparatus.
42、 3.3.1.1 Each test PRE shall be placed in a separate nonmetallic 19 L (5.0 gal) test container of DI water in accordance with ASTM D1193, Type IV requirements. The test container shall be filled with sufficient water to cover the test PRE as required by the reference electrode. TM0211-2011 NACE Inte
43、rnational 3 Figure 1: Schematic of test apparatus for CuSO4leaching test (NOTE: E connotes potential measurement.) 3.3.1.2 A refreshed portable Cu/CuSO4reference electrode (the standard electrode) shall be temporarily placed in the test environment for periodic monitoring. If a data-logging device i
44、s used, provisions shall be made to ensure that the standard electrode is not affected by the test conditions. 3.3.1.3 The standard electrode used shall be confirmed at least weekly against a minimum of two new or rehabilitated portable Cu/CuSO4reference electrodes. If the standard electrode deviate
45、s by more than 5 mV from both portable Cu/CuSO4 reference electrodes, the results shall be reported and the standard electrode rehabilitated as necessary to be accurate. NOTE: Extended contact with the test water adversely affects the standard electrode. 3.3.2 Stabilization Period 3.3.2.1 The potent
46、ial of the test PRE, referenced to the standard electrode, shall be allowed tRVWDELOLH6WDEOHVK all be defined as less than 0.1 mV/h change. 3.3.2.2 Data collected within the first 48 hours may be indicative of a stabilization period for the test PRE and the test environment. Deionized water Standard electro
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