1、 Standard Test Method Holiday Detection of Internal Tubular Coatings of 250 to 760 m (10 to 30 mils) Dry-Film Thickness 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 respe
2、ct preclude anyone, whether he 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, by implication
3、 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 interpreted
4、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 the interpret
5、ation 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 volunteers. Users of
6、 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 potential health
7、 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 protection prac
8、tices, 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 CAUTIONARY NOTICE: NACE International standards are subject to periodic review, and may be revised or withdrawn a
9、t any time without prior notice. 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. The user is cautioned to obtain the latest edition. Purchasers of NACE International standards may receive c
10、urrent information on all standards and other NACE International publications by contacting the NACE International Membership Services Department, 1440 South Creek Drive, Houston, Texas 77084-4906 (telephone +1 281 228-6200). Reaffirmed 2002-09-11 Reaffirmed March 1994 Reaffirmed September 1989 Appr
11、oved November 1985 NACE International 1440 South Creek Drive Houston, Texas 77084-4906 +1 (281) 228-6200 ISBN 1-57590-154-4 2002, NACE International NACE Standard TM0186-2002 Item No. 21218 TM0186-2002 NACE International i _ Foreword This NACE standard test method was prepared as a guide for evaluat
12、ing the application of polymeric coatings of 250 to 760 m (10 to 30 mils) to the internal surfaces of metallic tubular goods used in the oil and gas industry. It is not intended as a means of predicting the service life or service performance of these coatings. This test method is based on the curre
13、nt technology and experience of the petroleum production industry. NACE Standard TM03841addresses holiday detection of internal tubular coatings of less than 250 m (10 mils) dry-film thickness. This standard is intended for end users, manufacturers, applicators, corrosion engineers, and quality insp
14、ectors. This NACE standard was originally prepared by Task Group T-1G-9 on Holiday Testing of Plastic Linings, a component of Unit Committee T-1G on Protective Coatings, Elastomers, and other Nonmetallic Materials for Oilfield Use, and was reaffirmed by T-1G in 1989 and 1994. It was reaffirmed in 20
15、02 by Specific Technology Group (STG) 33 on Oil and Gas ProductionNonmetallics and Wear Coatings (Metallics). This STG is comprised of representatives from the oil and gas industry including consumers, producers, and interested individuals. This standard is issued by NACE International under the aus
16、pices of STG 33. 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, 4thed., Paragraph 7.4.1.9. Shall and must are used to state mandatory requirements. The term should is used to state something
17、considered good and is recommended but is not mandatory. The term may is used to state something considered optional. _ TM0186-2002 ii NACE International _ NACE International Standard Test Method Holiday Detection of Internal Tubular Coatings of 250 to 760 m (10 to 30 mils) Dry-Film Thickness Conten
18、ts 1. General . 1 2. Test Apparatus 1 3. Calibration and Test Procedure 3 4. Reporting Test Data 3 5. Safety 4 References 4 Figure 1Wet Probe 2 Figure 2Dry Probe. 2 _ TM0186-2002 NACE International 1 _ Section 1: General 1.1 This NACE standard provides a nondestructive test method for the detection
19、of holidays in a nonconductive coating film that has been applied to the inner wall (bore) of oilfield tubular goods. The apparatus and the recommended procedure for conducting the test are described, as are methods of reporting the test data. 1.2 The test method applies to coatings that have a spec
20、ified dry-film thickness of 250 to 760 m (10 to 30 mils). It is valid only for coatings that have not been in service or previously tested with a salt solution. When holiday testing is performed on coatings that have been in service or that have been previously tested for holidays with a salt soluti
21、on, there is a possibility of misleading results arising from surface contamination or salt bridging. The coating surface shall be free of materials that give added electrical insulation or that can mechanically damage the coating during the test. 1.3 A “holiday” is defined as a discontinuity in a p
22、rotective coating that exposes unprotected surface to the environment. For this test method, it means an area in an applied nonconductive coating that exhibits electrical conductivity when exposed to a known impressed voltage. 1.4 The voltage range for holiday detection is 4 to 12 V (DC) per m (100
23、to 300 V DC per mil) of dry-film thickness. The test voltage is determined by the type of probe, the maximum specified dry-film thickness, the type of coating application, and the customer. The voltage shall be measured between the probe and the pipe. 1.5 Several internal tubular coatings have speci
24、fied thickness ranges of 200 to 330 m (8 to 13 mils). These coatings shall be tested with a wet sponge at 67.5 V (DC) and 80,000 ohms (10%) resistance.1_ Section 2: Test Apparatus 2.1 Apparatus and materials required to perform this holiday test include a probe, a lance, a detector, and a conductive
25、 solution for the wet probe. 2.1.1 ProbeA wet probe or a dry probe may be used to conduct this test. Both probe types provide acceptable results. The calibration and test procedure (see Section 3) is identical for both probe types. Probe type shall be specified by the customer: 2.1.1.1 Wet ProbeThe
26、probe shall be a circular piece of sponge, conductive when wetted with a conductive water (e.g., tap water, not deionized or distilled). The sponge shall be 50 mm (2 in.) thick and shall be cut sufficiently larger than the inside diameter of the pipe to ensure 360 degrees of contact throughout the p
27、ipe length (see Figure 1). 2.1.1.2 Dry ProbeThe probe shall be a circular piece of dry conductive silicone rubber that is 3.0 mm (0.13 in.) thick and cut sufficiently larger than the inside diameter of the pipe to ensure 360 degrees of contact throughout the pipe length (see Figure 2). Either of the
28、 probe configurations shown in Figure 2 can be used if the 360-degree contact with the coating is obtained. The minimum test voltage shall be 4 V per m (100 V per mil) of maximum specified dry-film thickness. (See Paragraph 1.4) 2.1.1.3 Pipe sizes that are too large to use a 360-degree contact probe
29、 (e.g., 50-cm 20-in. diameter pipe) may require a probe that covers less than 360 degrees of the pipe. In this case, the probe shall be run through the pipe a sufficient number of times to cover the entire coated surface. In a very large-diameter pipe, a hand-held probe may be used, provided the ent
30、ire coated surface is holiday tested. 2.1.1.4 The probe back-up plates (Figures 1 and 2) shall be constructed of a material and in such a manner that they do not damage the coating. 2.1.2 LanceThe probe shall be attached to a lance that consists of a hollow, nonconductive tube to insulate the probe
31、lead from the pipe. TM0186-2002 2 NACE International 1. Metal pipe 5. Lance 2. Back-up plates for probe (each side, if required) 6. High-voltage lead (to terminal of detector) 3. Probe (sponge) 7. Metal conductor 4. Ground wire (to ground terminal of detector) 8. Coating FIGURE 1: Wet Probe 1. Metal
32、 pipe 5. Lance 2. Back-up plates for probe (each side) 6. High-voltage lead (to terminal of detector) 3. Probe (rubber) 7. Metal conductor 4. Ground wire (to ground terminal of detector) 8. Coating FIGURE 2: Dry Probe 2.1.2.1 The dry probe lead shall be a high-voltage wire with insulation capable of
33、 handling the maximum test voltage at a minimum of 100 mA (e.g., spark plug wire). This lead shall connect the detector to the probe. 2.1.3 Ground LeadAn insulated electrical conductor shall be connected to the outside pipe wall (clamped or affixed in such a manner that the coating or pipe is not da
34、maged) to serve as the electrical ground lead. It may be attached to the pipe rack if provision is made to TM0186-2002 NACE International 3 ensure a good contact to the pipe length being tested. This lead shall be of the same material as the probe lead. 2.1.4 DetectorThe detector shall be a high-vol
35、tage DC-type circuit containing the following: 2.1.4.1 A sensing or detector circuit possessing high sensitivity to small changes in current or voltage. It may be a bridge-, balance-, or reference-type circuit and shall contain input terminals for the probe and pipe leads. The equipment shall be des
36、igned for operation in a manner to limit the amount of current. 2.1.4.2 A DC power supply to the electrical circuit capable of being varied up to the required maximum voltage. 2.1.4.3 A fast-acting circuit to activate the alarm circuit consisting of a light and audible signal. 2.1.4.4 A preset or ad
37、justable alarm circuit that activates simultaneously with the spark and flow of current through the coating. _ Section 3: Calibration and Test Procedure 3.1 CalibrationThe detector shall be calibrated to the specified DC voltage to be used for holiday detection before the initial test and shall be r
38、ecalibrated after each 3,000 m (10,000 linear ft) of coating tested or at least every eight hours. The procedure is as follows: 3.1.1 Connect a high-voltage voltmeter (as specified by the holiday detection equipment manufacturer) between the probe and ground lead. 3.1.2 Turn the detector on and allo
39、w enough time for it to warm up (usually 5 to 10 min). Adjust the voltage on the detector in accordance with Paragraph 1.4. The voltage shall be measured between the probe and the pipe. 3.1.3 Turn off the detector, and then disconnect the voltmeter. 3.1.4 Turn the detector on, and allow enough time
40、for it to warm up. 3.1.5 Ensure that the alarm circuit activates the light and audible signals simultaneously with the spark when the probe is in close proximity to the pipe. 3.2 Testing Procedure 3.2.1 The probe shall be connected to the lance and held firmly in place. 3.2.1.1 The dry probe must be
41、 kept dry. 3.2.1.2 The wet probe sponge shall be kept saturated with the conductive water before each length of pipe is tested. Excess solution shall be squeezed out of the sponge. 3.2.2 The ground connection shall be checked on each length of pipe by touching the probe to bare metal to activate the
42、 alarm. 3.2.3 The probe shall be run through the pipe length and out the far end and then withdrawn from the pipe at a maximum rate of 18 m (60 linear ft) per minute. 3.2.4 The holiday record for each length of pipe shall consist of the number of holidays detected and counted on the return trip from
43、 end to end, i.e., as the probe is withdrawn. _ Section 4: Reporting Test Data 4.1 The test report shall indicate the number of holidays detected and counted in each pipe length. 4.1.1 Pipe lengths in which the alarm circuit is activated at such a rapid rate that the holidays cannot be counted easil
44、y shall be classified as “semi-continuous.” 4.1.2 Pipe lengths in which the alarm circuit is activated throughout the entire length of the pipe joint shall be classified as “continuous.” 4.2 Test voltage, type of probe, test solution, lance speed, equipment description, pipe description, coating thi
45、ckness, and number of holidays detected per joint shall be recorded. TM0186-2002 4 NACE International _ Section 5: Safety 5.1 Precautions shall be taken to prevent electrical shock during holiday testing. This is especially important when the test equipment is powered by line voltage. All the manufa
46、cturers safety instructions to prevent electrical shock shall be followed. 5.2 Personnel shall not operate in areas where flammable gases are present. 5.3 Personnel shall not operate in areas where flammable fluids are present if a possible fire hazard exists. _ References 1. NACE Standard TM0384 (latest revision), “Holiday Detection of Internal Tubular Coatings of Less Than 250 m (10 mils) Dry-Film Thickness” (Houston, TX: NACE). ISBN 1-57590-154-4
