1、 NACE International and IEEE Joint Standard Practice for Below-Grade Corrosion Control of Transmission, Distribution, and Substation Structures by Coating Repair Systems Approved 2014-12-10 (IEEE) 2015-01-28 (NACE) NACE International 15835 Park Ten Place Houston, Texas 77084-5145 +1 281-228-6200 IEE
2、E 3 Park Ave., 17th Floor New York, NY 10016-5997 +1 212-419-7900 2015, NACE International and Institute of Electrical and Electronics Engineers (IEEE) NACESP0215-2015/IEEEStd 1839-2014NACE SP0215-2015/IEEE Std 1839-2014 NACE SP0215-2015/IEEE Std 1839-2014 NACE International and IEEE NACE Internatio
3、nal and IEEE Joint Standard Practice for Below-Grade Corrosion Control of Transmission, Distribution, and Substation Structures by Coating Repair Systems Administered by NACE Specific Technology Group (STG) 41, “Electric Utility Generation, Transmission, and Distribution Approved 2015-01-28 NACE Boa
4、rd of Directors Sponsor Transmission and Distribution (PE/T (2) excavate and inspect the selected structure; (3) assess the level of risk to the structure in terms of corrosion attack and degradation to the existing coating system; (4) prioritize structures to be repaired based on those findings as
5、to whether coating repair is needed and if so, to what extent; and (5) apply repair coatings to the structure, if applicable. 1.1.1 This standard is limited to assessment and repair of coating applied below grade and in the transition zone portions of carbon steel and galvanized steel electric trans
6、mission towers, grillage, and substation structures. It does not address assessment and repair of coatings above the transition zone. For the purposes of this standard, this area comprises of the below-grade portion, the transition zone, and is defined as that portion of the coating exposed up to 60
7、0 mm (24 in) above grade. 1.1.2 This standard does not address structural damage assessment, structural repairs, weathering steel, or structural integrity. This standard does not address concrete foundations or above-grade attachment points including anchor rods, attachment nuts, and noncoated groun
8、d sleeves. This standard does not address continuous immersion environments. This standard does not provide guidelines and repair procedures for coating systems for every specific situation because of the complexity and diverse nature of conditions to which buried structures may be exposed. 1.2 Purp
9、oseThis standard provides guidelines and repair procedures for coating systems most commonly applied to below-grade electric transmission structures and typical of what inspection and coating repair crews most often find. _ Section 2: General 2.1 This standard applies to the repair of below-grade el
10、ectric transmission structures that have up to 10% degradation of the excavated coated area as defined by SSPC(1)-VIS 21and are subject to coating repair or, in some cases, local structural repairs. Electric transmission structures that have more than 10% coating degradation should be evaluated for
11、structural repairs in addition to coating repairs. For the purposes of this standard, this area is composed of the below-grade portion, the transition zone, defined as that portion of the coating exposed up to 600 mm (24 in) above grade. Depth of current excavation and additional further excavation
12、is dependent on the corrosiveness of soil conditions. 2.2 This standard refers to industry standards from ASTM International (ASTM),(2)NACE, and SSPC. In some cases these organizations have developed equivalent standards for a test method specified in this standard. It is not the intention of this s
13、tandard to specify one organizations standard over another when equivalent standards are available. Where applicable, equivalent standards may be interchanged as deemed appropriate. 2.3 Before any of the guidelines of this standard are implemented, the inspection, assessment, and repair process shal
14、l be defined and agreed on in advance by the owner and all parties involved. Acceptance and rejection criteria, in addition to the methods and standards used to make determinations, shall be established before commencement of work. A plan of action that identifies priorities, objectives, and expecta
15、tions for each aspect of the program shall also be developed. Typical considerations vary, but should include topics such as: 2.3.1 Project management (a) Planning, scheduling, logistics, documentation, and reporting; (b) Regulations, ordinances, permits, and maintenance of traffic (MOT); (c) Labor,
16、 skills, and qualification of personnel; (d) Safety, health, and environmental regulations; (1)SSPC: The Society for Protective Coatings (SSPC), 40 24th Street, 6th Floor, Pittsburgh PA 15222-4656. (2)ASTM International (ASTM), 100 Barr Harbor Dr., West Conshohocken, PA 19428-2959. NACE SP0215-2015/
17、IEEE Std 1839-2014 2 NACE International and IEEE (e) Quality control; and (f) Budgeting. 2.3.2 Inspection, testing, and assessment procedures (a) The use of recognized standards and work protocol; (b) Acceptance and rejection criteria; (c) Methods of measurements; and (d) Equipment, tools, and calib
18、ration. 2.3.3 Selection and application of repair materials (a) Performance specifications and expectations; (b) Materials specifications and application parameters; (c) Substrate type and condition; (d) Surface preparation requirements; (e) Repair coating system (e.g., ease of repair, compatibility
19、 with existing coating system and material substrate, cure time, pot life, and backfill); and (f) Environment and service condition considerations. 2.4 All of the above are key elements that can impact the overall success of a repair coating project. A preproject meeting that involves all concerned
20、parties provides a means to determine the scope of work and expectation for deliverables. Good communication and an understanding of the priorities and objectives before implementing a coating repair program promote quality workmanship and long-term coating performance. _ Section 3: Inspection and A
21、ssessment 3.1 A desk review of maps and structure data shall be performed before inspection to identify areas of priority as they pertain to below-grade corrosion potential. Each of the factors shown below is an important consideration that should be weighed based on site-specific details: (a) Age;
22、(b) Geographic locations; (c) Known environmental factors including atmosphere, climate, soil corrosiveness (pH, redox potential, moisture value, organic content, chloride content, sulfate content, and soil resistivity); (d) Failure and maintenance history; (e) Structure type; (f) Presence of a coat
23、ing system, type, and vintage; (g) Compatibility of the existing coating system to the intended repair coating system; and (h) Characteristics of the repair coating system. NACE SP0215-2015/IEEE Std 1839-2014 NACE International and IEEE 3 3.2 Based on the information obtained, a program shall be dev
24、eloped to inspect areas of highest corrosion risk first, moderate risk second, and lowest risk last. Basic guidelines for determining corrosion risk are shown in Table 1. Table 1 Examples of Corrosion Risk Minimal Corrosion Risk Moderate Corrosion Risk High Corrosion Risk New structures and/or struc
25、tures located in areas with no previous corrosion failures Located in areas with previous corrosion failures Located in areas with previous corrosion failures Environment: Dry environment Environment: Wet environment/moderate exposure to water table Environment: Extended periods of time of wetness/h
26、igh water table Coarse soils, such as sands and gravels, that promote free circulation of air Finely textured soils with higher water holding capacity such as clays and silts Finely textured soils with higher water holding capacity such as clays and silts and/or contaminated soils (presence of coke,
27、 coal, carbon, or organic waste) Soils with resistivity of greater than 10,000 cm Little or no chlorides and/or sulfates (50 ppm) and/or sulfates (500 ppm) and other corrosive ions Soils with resistivity of less than 2,000 cm Oxidizing or reducing soils Extremely low or high pH Existence of chloride
28、s (50 ppm) and/or sulfates (500 ppm) and other corrosive ions Rural environments with absence of agricultural chemicals Industrial and marine atmosphere Industrial and marine atmosphere, polluted conditions, agricultural chemicals High-performance coating Suspect coating system Suspect coating syste
29、m Structure design not an issue Structure design may be an issue Structure design is an issue Stray currents not an issue Stray currents may be an issue Stray currents known to be an issue 3.3 Inspection 3.3.1 The electric transmission structure selected for inspection should be photographed with ap
30、propriate identification markings and Global Positioning System (GPS) coordinates obtained. Forms to record relevant inspection, assessment, and repair data shall be used to document all work and findings. 3.3.2 The condition of the area to be repaired must be determined to specify the appropriate s
31、urface preparation and coating repair procedure. 3.3.3 If a partial excavation is required to inspect the condition of the steel and coatings below grade and at the transition zone, the excavation shall be performed in accordance with the Occupational Safety and Health Administration (OSHA)(3) U.S.
32、Code of Federal Regulations(4) (CFR) Title 29, Section 1926.2A partial excavation is defined as removal of soil by shovel or other appropriate tool around the electric transmission structure and up to 600 mm (24 in) below grade. Depth of current excavation and additional further excavation is depend
33、ent on the corrosiveness of soil conditions. 3.3.4 Care shall be taken not to damage the coating while performing the partial excavation. If damage is caused, repair to the coating is required. 3.3.5 The surface of the partially excavated electric transmission structure shall be visually inspected f
34、or: (a) Coating loss; (b) Corrosion, pitting; (3) Occupational Safety and Health Administration (OSHA), U.S. Department of Labor, 200 Constitution Ave. NW, Washington, DC 20210. (4) U.S. Code of Federal Regulations (CFR), U.S. Government Printing Office (GPO), 732 N. Capitol Street, NW, Washington,
35、DC 20401. NACE SP0215-2015/IEEE Std 1839-2014 4 NACE International and IEEE (c) Coating adhesion problems; (d) Coating delamination; (e) Coating discoloration; (f) Underfilm corrosion; (g) Blistering or bubbling; (h) Cracking, crazing, or other defective visual appearance of the coating; (i) Contami
36、nation; and (j) Mechanical damage (e.g., gouges, nicks, and/or scrapes). 3.3.6 If any of the above features are observed, they shall be assessed and documented to determine the overall coating condition, degree and extent of damage, or for the repair required to obtain the necessary level of protect
37、ion to the electric transmission structure, as described in the following sections. 3.3.7 Testing and Assessment Procedures 3.3.7.1 A wide array of test methods, protocols, and equipment may be used to assess the level of degradation to a coating system. The methods used in this standard are industr
38、y-recognized standards and protocols. 3.3.7.2 The coating assessment portion of this standard was adapted from SSPC-PA Guide 43to assess and classify coating condition (Nondeteriorated; Slightly to Moderately Deteriorated; Deteriorated; Severely Deteriorated; or Totally Deteriorated) in terms of coa
39、ting degradation, as shown in Table 2. Supplemental images and diagrams that represent various degrees of spot, general, and pinpoint rusting issues on painted steel surfaces are available in SSPC-VIS 2 and ASTM D610.43.3.7.3 Assessment of the overall coating condition shall be performed in accordan
40、ce with the following procedures. 3.3.7.3.1 The area to be evaluated may be localized or general. In locations where coating defects are observed, the extent and size of areas of concern shall be determined. In accordance with ASTM D6677,5a sharp utility knife may be used to gently probe the coating
41、 defect area and assess disbondment characteristics. The nonadhering or damaged area of the coating shall be probed until tightly adhering coating is located. Areas of concern should be marked, including approximately 50 mm (2 in) beyond the damaged border into tightly adhered coating. 3.3.7.3.2 If
42、mechanical damage or coating degradation is observed, the inspector shall determine whether the substrate is exposed. If so, the damaged or degraded area shall be measured and the extent determined. Whether the damaged or degraded area impairs coating integrity only, coating repairs may be applied.
43、If the damaged or degraded area affects the ability of a load-bearing member to function in a safe and sustainable manner, an engineering evaluation is required. 3.3.7.3.3 If corrosion products of steel substrate (red rust) or corrosion products of zinc or galvanized steel (white rust) are observed,
44、 the inspector must determine whether the corrosion is general or pitting. If general corrosion is found, the extent and characteristics of the corrosion should be recorded using Table 2. 3.3.7.3.4 If visible pitting is found in the substrate, the bare areas of exposed surface shall be brushed with
45、a nonmetallic brush for closer examination. If depth of pitting is questionable, the depth of corrosion pitting shall be measured by placing the probe of the pit depth indicator at the deepest pit(s) to obtain pit depth in accordance with the gauge manufacturers recommendations. Depending on the dep
46、th of the pit(s), an engineering evaluation may be required to determine structure integrity and repair methods. 3.3.7.3.5 If coating delamination is observed, the surrounding areas should be visually inspected to determine the extent of the delamination. Underfilm corrosion, including blistering or
47、 bubbling. should also be checked. Refer to Table 2 to assess and classify these problems. 3.3.7.3.6 Testing to evaluate coating integrity that may not be visually apparent may include: NACE SP0215-2015/IEEE Std 1839-2014 NACE International and IEEE 5 (a) ASTM E376 or SSPC-PA 2.6,7NOTE: Magnetic mea
48、surement on galvanized steel electric transmission structures provides the total thickness of both the galvanizing and the protective coating. (b) Discontinuity (holiday) testing. (c) Adhesion testing in accordance with ASTM D3359.8NOTE: Cross hatch or X-scribe testing are destructive to the coating
49、 system and require coating repair after testing is performed. 3.3.7.3.7 Table 2 provides guidelines for determining the coating system condition and degree of deterioration. For the purposes of Table 2, the term “rust” refers to red rust. Red rust is defined as corrosion products of a substrate of carbon steel. 3.3.7.3.8 Table 2 does not address white rust. It is assumed that white rust, common to galvanized
