Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard. This method will g, however, find any thin spots in the coating. This method is considered destructive because the high voltages involved generally destroy the coating at thin spots. Get access to more than 20, documents addressing all aspects of corrosion including:. About Us How we tackle the issue What will you get? Tested coating thickness is up to 12 mm.
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A number in parentheses indicates the year of last reapproval. It is effective on filmsup to 0. It should be noted, however, that this methodwill not detect thin spots in the coating. This may be consideredto be a nondestructive test because of the relatively lowvoltage. This method can be used on any thickness ofpipeline coating and utilizes applied voltages between and20 V d-c. The values given inparentheses are for information only.
It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. Referenced Documents2. These are used on the coatings of relatively high-electricalresistance when such coatings are applied to the surface ofmaterials of low-electrical resistance, such as steel pipe.
Summary of Test Methods4. This electrical contact will activate an alarmalerting the operator of the incidence of a holiday. Significance and Use5. Current edition approved July 1, Published July Originally approvedin Last previous edition approved in as G62 — 07 United States1through the coating.
This method will not, however, find anythin spots in the coating. This method will determine theexistence of any gross faults in thin-film pipeline coatings. This methodcan be used to verify minimum coating thicknesses as well asvoids in quality-control applications.
Aground wire connects the detector with the low-resistancemetal surface. Reagents and Materials7. NOTE 1—Ordinary tap water will suffice to wet the sponge electrodewhen inspecting coatings up to 0.
On filmsbetween 0. Test Specimen8. Standardization of Instruments9. This isused more commonly with Method B where voltage may varyfrom test to test but can also be used for verification of thevoltage on a Method A test.
Most units can be reset to any predetermined sensitivityvalue in this manner. Procedure for Method A Then tighten the clamps with the screwuntil they are well down into the sponge electrode.
Attach theground wire lead with battery clamp and the wand to theterminals. Clip the ground wire to some point where the metalsurface is bare. Now touch the electrode to a second pointwhere the surface is bare and note that the audible signal willbe activated. The detector is now ready to operate by passingthe damp sponge over the coated surface.
When a holiday ispicked up by the audible alarm, the electrode can be turned onend and the exact spot of failure can be noted by searching withthe tip of the electrode. This is particularly important if formed surfacesare to be inspected. If the surface is in an environment whereelectrolytes might form on the surface, such as salt spray, washthe coated surface with fresh water and allow to dry beforetesting. Take care to keep the electrolyte at least This type of holiday detector will not detect thinspots in pipeline coatings.
Procedure for Method B NOTE 2—The dielectric breakdown voltage per millimetre mil can bedetermined for each coating experimentally as follows: Increase theholiday detector voltage over a known coating thickness and measure thevoltage at the point where the detector will just begin to ring.
Divide thisvoltage by the known coating thickness to obtain the amount of volts permillimetre mil. Therefore, they are useful for testing voids,pinholes and thin spots in the coating, but would not be usefulas a coating thickness quality control tool. Plug the ground wireinto the holiday detector. Plug the searchingelectrode into the holiday detector. Turn on the holidaydetector.
The detector will ring if itpasses any void, pinhole, or area of the coating thinner than theminimum allowable thickness. When a holiday is detected bythe audible alarm, the electrode can be repositioned to deter-mine the exact holiday area by observing the origin of the sparkjump.
Dryness is critical in a high voltage test. Takecare to keep the electrode at least Precision and Bias Specimens that were not adjacent in the as-producedcondition, or were taken from different lengths of pipe, mayrepresent differing process conditions.
No value for bias can be determined. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.
This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters.
Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.
Mukree Historical Version s — view previous versions of standard. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. This standard is subject to ast, at any time by the responsible technical committee and must be reviewed every? Take care to keep the electrolyte at least Active view current version of standard.
ASTM G62-07 PDF
Yosar Historical Version s — view previous versions of standard. Link to Active This link will always route to the current Active version of the standard. It should be noted, however, that this method will not detect thin spots in the coating. It is the responsibility of the user of this standard to establish appropriate y and health practices and determine the applicability of regulatory limitations prior to use. It is effective on films up to 0. This method can be used to verify minimum coating thicknesses as well as voids in quality-control applications.
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