1、 Standard Practice Aboveground Survey Techniques for the Evaluation of Underground Pipeline Coating Condition 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 respect preclud
2、e 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, by implication or
3、 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 as
4、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 interpretati
5、on 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 th
6、is 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 an
7、d 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 practic
8、es, 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 CAUTIONARY NOTICE: NACE International standards are subject to periodic review, and may be revised or withdrawn at a
9、ny 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 revision. The user is
10、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 First Service Department, 1440 South Creek Dr., Houston, Texas 77084-4906 (telephone +1 2
11、81-228-6200). Approved 2009-03-21 NACE International 1440 South Creek Drive Houston, Texas 77084-4906 +1 281-228-6200 ISBN 1-57590-226-5 2009, NACE International NACE Standard TM0109-2009 Item No. 21254 TM0109-2009 NACE International i _ Foreword This standard test method presents various techniques
12、 for aboveground evaluation of the coating condition of buried metallic pipelines. It is specifically intended to address buried onshore metallic pipelines and is based on available technology and methods that have successfully demonstrated evaluation of the coating condition of buried pipelines. If
13、 new technology is applicable and is not included in this standard, the manufacturer is encouraged to submit verifiable data to NACE Specific Technology Group (STG) 35, “Pipelines, Tanks, and Well Casings,” for review and possible inclusion in the next revision of this standard. The provisions of th
14、is standard shall be applied by personnel who have acquired by education and related practical experience the principles of cathodic protection (CP) of buried metallic piping and the proper use of the survey techniques in this standard. Codes, laws, and regulations in a local geographic area may req
15、uire supplement to or deviation from this standard. This standard provides testing procedures to comply with the requirements specified on the indirect inspection step of the NACE external corrosion direct assessment1(EDCA) process. The data gathered using these testing procedures may be submitted t
16、o the end user using the joint NACE/PODS SP0507.2This standard is intended for use by individuals and teams planning and implementing aboveground evaluation of the coating condition of underground metallic pipelines. These individuals include engineers, operations and maintenance personnel, technici
17、ans, specialists, and inspectors. Users of this standard must be familiar with applicable pipeline safety regulations for the jurisdiction in which the pipeline operates. This includes all regulations requiring specific pipeline integrity assessment practices and programs. This standard was prepared
18、 by Task Group (TG) 294, “Pipeline Coating: Aboveground Survey Techniques for the Evaluation of Underground Pipeline Coating Condition.” TG 294 is administered by STG 35 and is sponsored by STG 03, “Coatings and Linings, Protective: Immersion and Buried Service” and STG 05, “Cathodic/Anodic Protecti
19、on.” This standard is issued by NACE under the auspices of STG 35. 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
20、mandatory. 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. _ TM0109-2009 ii NACE International _ NACE International Standard Practice Aboveground Survey Techniques for the Evaluation of
21、Underground Pipeline Coating Condition Contents 1. General 1 2. Definitions 3 3. Alternating Current Attenuation Survey (Electromagnetic Method) 7 4. Alternating Current Voltage Gradient Survey 18 5. Pearson Survey . 26 6. Direct Current Voltage Gradient Survey 27 References 32 FIGURES Figure 1: Mag
22、netic field distortion example 12 Figure 2: Current gain/loss profile . 14 Figure 3: Current attenuation representation as logarithm of the current . 15 Figure 4: Current attenuation plot . 16 Figure 5: Average coating conductance in microsiemens/m (S/m) 17 Figure 6: Basic flow of ACVG survey curren
23、t 19 Figure 7: Pinpointing a fault in X- and Y-axis 22 Figure 8: Indication SeverityFinding Maximum Indication Value 23 Figure 9: A typical graph of ACVG reading . 25 _ TM0109-2009 NACE International 1 _ Section 1: General 1.1 Aboveground Survey Techniques 1.1.1 This standard presents acknowledged p
24、rocedures for the application of aboveground techniques to evaluate the coating condition of underground metallic pipelines. 1.1.2 This standard does not designate practices for specific situations; the complexity of some underground pipeline and environmental conditions preclude standardizing the a
25、pplication of some of the coating evaluation techniques. Deviation from this standard may be warranted in specific situations, provided those responsible can demonstrate that the objectives expressed in this standard have been achieved. 1.1.3 This standard does not include procedures for close-inter
26、val pipe-to-soil potential surveys (CIS). CIS procedures are covered in NACE SP0207.3 1.1.4 Alternating current (AC) attenuation surveys are used to provide an assessment of the overall quality of the pipe coating section by section; however, this technique is not typically effective in identifying
27、individual holidays. 1.1.5 Direct current (DC) and AC-voltage gradient surveys are used to evaluate in detail the coating condition on buried pipelines and identify and classify coating holidays. 1.1.6 The Pearson survey, named after J.M. Pearson (the individual who developed the technique), is used
28、 to locate coating holidays. 1.1.7 The pipeline operator must determine which survey techniques are suitable for providing required coating condition assessment information for each pipeline or pipeline section. 1.2 Pre-Survey Considerations 1.2.1 None of the aboveground coating evaluation technique
29、s included in this standard are capable of detecting pipeline steel that is electrically shielded from the bulk electrolyte by disbonded coatings with no electrically continuous path to the electrolyte. 1.2.2 The indirect inspection tools covered in this standard are less sensitive when pipe burials
30、 exceed normal depth ranges. Field conditions and terrain may affect depth and detection sensitivity. 1.2.3 The following information should be gathered and analyzed to establish applicability of the aboveground coating condition survey techniques for any given pipeline or pipeline section. The item
31、s in the list are not intended to address all possible variables that may affect applicability of a technique to a specific pipe section: 1.2.3.1 Pipeline diameter and pipe-wall thickness, fluid transmitted, temperature, direction of flow, and operating pressure; 1.2.3.2 Pipeline coating type, age,
32、and whether pipeline/sections are under concrete; 1.2.3.3 Route maps and cathodic protection records, when available; 1.2.3.4 Whether or not in-line inspection (ILI) correlation point locations are used together with global positioning system (GPS) information to compare known aboveground and underg
33、round survey data; 1.2.3.5 Pipeline depth-of-cover and soil type; TM0109-2009 2 NACE International 1.2.3.6 Whether or not the pipeline section is under frozen ground; 1.2.3.7 Right-of-way (ROW) condition, including ground cover above the pipeline such as pavement, concrete, wetlands, bodies of water
34、, and rocky terrain; 1.2.3.8 Location, separation distance, and electrical isolation condition of metallic structures adjacent to the pipeline; 1.2.3.9 Location, separation distance, and electrical isolation condition of underground parallel pipelines in the pipeline ROW; 1.2.3.10 Location and elect
35、rical isolation condition of casings; 1.2.3.11 Location, type, and status of CP systems influencing the pipeline section; 1.2.3.12 Location of foreign CP systems influencing the pipeline section; 1.2.3.13 Location and status of CP test points; 1.2.3.14 Location and status of electrical isolation fro
36、m aboveground features, such as valves and piping in compressor or pump stations, and electrical grounding; 1.2.3.15 Location of overhead high-voltage AC transmission lines parallel to or crossing the pipeline ROW; 1.2.3.16 Location of buried power cables parallel to or crossing the pipeline ROW; an
37、d 1.2.3.17 Location and influence, if known, of DC traction systems, industrial facilities utilizing DC induction or welding equipment, or overhead DC power lines parallel to or crossing the pipeline ROW. 1.3 Qualifications 1.3.1 The provisions of this standard should be applied under the direction
38、of competent persons who, by reason of knowledge of the physical sciences and the principles of engineering and mathematics acquired by education and related practical experience, are qualified to engage in the practice of corrosion control on buried or submerged metallic piping systems. Such person
39、s may be registered professional engineers or persons recognized by NACE as corrosion specialists, CP specialists, corrosion or CP technologists, or the equivalent if their professional activities include suitable experience in the application of the aboveground coating evaluation techniques include
40、d in this standard. 1.3.2 Persons performing aboveground surveys included in this standard for the evaluation of underground pipeline coatings (who, for the purpose of this standard, are called surveyors) must be qualified to understand and follow the applicable procedures contained in this standard
41、 or work under the direct supervision of a person who is qualified. Such persons may be recognized by NACE as CP testers, corrosion or CP technicians, technologists, specialists, or the equivalent if their professional activities include suitable experience in performing aboveground surveys for the
42、evaluation of underground pipeline coatings included in this standard. 1.4 Safety Considerations 1.4.1 Appropriate safety and regulatory precautions, including the following, shall be observed when electrical measurements are made: 1.4.1.1 Only qualified persons shall install, adjust, repair, remove
43、, or test impressed-current CP equipment; 1.4.1.2 Only qualified persons shall install, adjust, repair, remove, or test the equipment detailed in this standard; TM0109-2009 NACE International 3 1.4.1.3 Appropriate personal protection equipment (PPE) shall be used where applicable; 1.4.1.4 Properly i
44、nsulated test lead clips and terminals should be used to avoid contact with unanticipated high voltage. Insulated test lead clips and terminals must be rated for the highest anticipated voltage that is to be encountered during the survey. Test clips should be attached one at a time using a single ha
45、nd technique for each connection; 1.4.1.5 Caution should be used when long test leads are extended near overhead high-voltage power lines that can induce hazardous voltages onto the test leads. Users should refer to NACE SP01774for additional information; 1.4.1.6 Caution should be used when tests ar
46、e conducted at electrical isolation devices. Appropriate voltage detection instruments or voltmeters with insulated test leads should be used to determine whether hazardous voltages exist before proceeding with further tests; 1.4.1.7 Testing should be avoided when adverse weather conditions are pres
47、ent, such as thunderstorms. Remote lightning strikes can create hazardous voltage surges that travel along the pipe under test; and 1.4.1.8 Caution should be used when work is performed near streets, roads and other locations subject to vehicular and pedestrian traffic. Appropriate measures such as
48、barricades, high visibility clothing, flagging, and traffic control devices should be used when conditions warrant or as required by safety and regulatory agencies responsible for governing traffic control. 1.4.2 Project-specific safety considerations should include, but are not limited to, the following factors: 1.4.2.1 Wildlife indigenous to the area, to include identification, avoidance procedures, and emergency procedures; 1.4.2.2 Hazardous plants, insects, or reptiles indigenous to the area, including identification, av
