1、t : i E R : A 7 1 O N A L NACE Standard SPO592-2006 (formerly RP0592-2001) Item No. 21057 Standard Practice Application of a Coating System to Interior Surfaces of New and Used Rail Tank Cars in Concentrated (90 to 98%) Sulfuric Acid Service This NACE International standard represents a consensus of
2、 those individual members who have reviewed this document, its scope, and provisions. Its acceptance does not in any 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 w
3、ith this standard. Nothing contained in this NACE International standard is to be construed as granting any right, by 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
4、 liability for infringement of Letters Patent. This standard represents minimum requirements and should in no way be 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
5、 may negate the usefulness of this standard in specific instances. NACE International assumes no responsibility for 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 accord
6、ance with its governing procedures and policies which preclude the issuance of interpretations by individual volunteers. Users of this NACE International standard are responsible for reviewing appropriate health, safety, environmental, and regulatory documents and for determining their applicability
7、 in relation to this standard prior to its use. This NACE International standard may not necessarily address all potential 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 thi
8、s NACE International standard are also responsible for establishing appropriate health, safety, and environmental protection practices, in consultation with appropriate regulatory authorities if necessary, to achieve compliance with any existing applicable regulatory requirements prior to the use of
9、 this standard. CAUTIONARY NOTICE: NACE International standards are subject to periodic review, and may be revised or withdrawn at 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
10、initial publication. 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,
11、Texas 77084-4906 (telephone +I 281228-6200). Reaffirmed 2006-03-15 Reaffirmed 2001-09-12 Approved 1992-04-26 NACE International 1440 South Creek Drive Houston, Texas 77084-4906 +I 281/228-6200 ISBN 1-57590-132-3 O 2006, NACE International SPO592-2006 Foreword A large number of commercial 93% sulfuri
12、c acid (H2S04) shipments in the United States and Canada are made by rail in carbon steel tank cars. Concentrated sulfuric acid is an oxidizing agent and a desiccant. The major problems in its handling and storage relate to its hygroscopic nature (absorption of atmospheric humidity), its exothermic
13、reactivity with water on dilution, and velocity effects that erode the otherwise protective films of corrosion products. Corrosion rates of approximately 0.25 mm/year (0.01 O in./year) have been measured in static storage tanks and tank cars that haul concentrated sulfuric acid. To cope with this un
14、iform corrosion over a 40-year service life, 10 mm (0.4 in.) of extra wall thickness would be required on a tank car. The addition of this extra wall thickness would add substantially to the tank cars weight and result in severe reductions in carrying capacity. An even more serious problem is that u
15、niform corrosion is invariably accompanied by severe localized corrosion in the top halves of tank cars. This localized corrosion, called hydrogen grooving, produces deep vertical grooves in localized bands that extend along the sides and across the heads of tank cars. Hydrogen grooves can progress
16、through the steel far more rapidly than uniform corrosion, and can cause substantial damage after short periods of service. Extra wall thickness is not sufficient to cope with hydrogen grooving. Copper-bearing steels also have been used to improve resistance to sulfuric acid corrosion, but this has
17、not been successful. Painting the exterior surfaces of the tank cars with a heat-reflecting color to keep the acid temperature as low as possible has reduced corrosion rates, but has not eliminated the problem. Anodic protection is another option that is sometimes considered. Industry consensus poin
18、ts to internal coatings as a necessary protective measure for tank cars transporting concentrated sulfuric acid and to ensure product purity. Many shippers of sulfuric acid apply a protective coating (usually a baked phenolic) to the interior surfaces of tank cars and specify a nominal steel corrosi
19、on allowance of 3.2 mm (0.13 in.) in the event of coating failure. The life expectancies of these coatings are highly dependent on the quality of application. For this reason, the proper application and inspection of interior coatings is very important to the maintenance of tank cars hauling sulfuri
20、c acid. This standard practice provides guidelines for the high-quality application, surface preparation, inspection, and testing of coatings for the interior surfaces of rail tank cars handling shipments of concentrated sulfuric acid at ambient temperatures. This NACE standard is intended for use b
21、y tank car owners, coating manufacturers, and coating applicators for the auditing of the facilities, equipment, and personnel that satisfy the requirements for tank car coating systems in this severe service. This standard was originally developed in 1992 by Task Group (TG) T-14C-1, a component of
22、Unit Committee T-14C on Rail Equipment Corrosion. It was reaffirmed by STG 43 in 2001 following review by TG 061. TG 061 is administered by Specific Technology Group (STG) 43 on Land Transportation, and sponsored by STG 03 on Protective Coatings and Linings-lmmersion/Buried and STG 36 on Process Ind
23、ustry-Chemicals. It was reaffirmed by STG 43 in 2006, and is issued by NACE under the auspices of STG 43. 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, 4th ed., Paragraph 7.4.1.9. Shall and
24、must are used to state mandatory requirements. The term should is used to state something good and is recommended but is not mandatory. The term may is used to state something considered optional. NACE International I SPO592-2006 NACE In tern at ional St and a rd Practice Application of a Coating Sy
25、stem to Interior Surfaces of New and Used Rail Tank Cars in Concentrated (90 to 98%) Sulfuric Acid Service Contents 1. General . . 2. Definitions . 3 . 4 . 4 . 5 8. Coating of Particular P 11. Safety . Refe re n ces . . 7 and Equipment for Application of a Coating System . 10 Report Form . II NACE I
26、nternational SPO592-2006 Section 1: General 1 .I This standard describes a procedure for the application of a coating system to the interior sutfaces of new and used railroad steel tank cars used primarily in the transportation of concentrated (90 to 98%) sulfuric acid at ambient pertaining to DOT 1
27、1 1Al00W-2 tanks. temperatures. The requirements for sutface preparation, qualified inspection of the completed coating system, and 1.4 The minimum as-built wall thicknesses of metal testing by the use of adequate, readily available instruments sutfaces to be coated in accordance with this standard
28、are also covered in this standard. should be 11 mm (0.43 in.). 1.3 In addition to adhering to the conditions set forth in this standard, tank cars haulin concentrated sulfuric acid must comply with U.S. DO? and AAR” specifications 1.2 For the purposes of this standard, the term concentrated sulfuric
29、 acid broadly refers to acid in the concentration range of 90 to 98%. Commercial sulfuric acid is usually handled at 93% because that concentration has the minimum freezing point of -34C (-30F) for solutions of sulfuric acid in water. Sulfuric acid at 98% would be more economical to ship per unit we
30、ight of acid; however, it is more corrosive to carbon steel than 93% acid, and has a higher freezing point of approximately 7C (45F). All concentrations of sulfuric acid can contain impurities that can significantly alter its inherent corrosion characteristics. 1.5 Liquid coatings used in this stand
31、ard may be hazardous and therefore basic safety precautions regarding the handling and application of these coating materials and solvents should be used. Chapter 1 of NACE TPC No. Z3 contains more detailed information. The material safety data sheet (MSDS) supplied by the coating manufacturer provi
32、des additional information relative to the coating and current government regulations. 1.6 This standard does not provide a full treatise on corrosion of steel by concentrated sulfuric acid; this is an extensive subject in its own right. Section 2: Definitions Coating: A liquid, liquefiable, or mast
33、ic composition that, after application to a sutface, is converted into a solid readings for a coating. protective, decorative, or functional adherent film. For the purpose of this standard, any paint-type protective covering applied in one or more coats to the interior of the rail tank car to act as
34、 a barrier between the base metal and the commodity. Measurement: An average of three or more film thickness Pinhole: Coating defect characterized by a small pore-like flaw that, when extended entirely through the coating, appears as a discontinuity. A pinhole in the finish coat may not appear as a
35、discontinuity. Contracting Authority: The person or firm that is responsible for the approval and purchase of a completed tank car coating system. Contractor: The firm that is executing the coating work specified. Discontinuity: A void, crack, thin spot, foreign inclusion, or contamination in a coat
36、ing that significantly lowers its dielectric strength. It may also be identified as a holiday or pinhole. Holiday: A discontinuity in a protective coating that exposes unprotected sutface to the environment. Holiday Detector: A device that locates discontinuities in a coating applied to a conductive
37、 sutface. Quality Assurance: Comprises all those planned and systematic actions necessary to provide specified documentation and adequate confidence that the tank car coating system will petform satisfactorily in service. Quality Control: Comprises those quality assurance actions related to the phys
38、ical characteristics of the entire coating systems application as a means of providing compliance with specified requirements. Reading: A single film-thickness gauge determination for a coating. Shelf Life: The maximum length of time that a coating can be stored in a factory-sealed container, at a t
39、emperature range specified by the coating supplier, before application. . (I) U.S. Department of Transportation (DOT), 400 7th Street SW, Washington DC 20590. () Association of American Railroads (AAR), 50 F Street NW, Washington DC 20001-1564. NACE International 1 SPO592-2006 Tank Car Owner: The pe
40、rson or firm that owns the tank car 3.1 3.2 (The person or firm may also be the contracting authority.) Section 3: Areas of Responsibility Contracting Authority 3.1.1 An inspection of the contractors facilities and equipment should be conducted before the coating project is sent out for bids. 3.1.2
41、A prejob conference shall be scheduled prior to beginning the coating work. The conference shall include representatives of the tank car owner, contracting authority, inspection agency, coating manufacturer, and contractor. The contractor shall include the quality control supervisor and responsible
42、shop personnel directly involved in the coating application. 3.1.3 This standard shall be reviewed along with any other related specifications at the prejob conference. Any points of misunderstanding regarding applicable standards shall be clarified. 3.1.4 Inspection forms shall be approved by the c
43、ontracting authority. 3.1.5 Quality assurance shall be the responsibility of the contracting authority. 3.1.6 If deemed essential to the proper sutface preparation of the tank car, the contractor shall be provided with information in writing about the last consignment carried in the tank car. 3.1.7
44、The contracting authority shall specify the type of coating, the color, the number of coats to be applied, and the minimum and maximum allowable film thickness for each coat. Contractor to all areas where work is in progress on subject tank cars. 3.2.4 Assurance shall be given by the contractor that
45、 the work is being petformed in compliance with all applicable regulations. 3.2.5 Subject to applicable regulations, the contractor is responsible for personnel safety in the handling, application, and disposal of the specified coatings. In accordance with OSHA3 or the appropriate national regulator
46、y agency, current MSDS for each component of a coating system to be applied shall be retained on file and made available to each person using the materials. 3.2.6 Current coating application instructions shall be retained at the application site. 3.2.7 The contractor shall forward the completed insp
47、ection forms to the contracting authority and retain a copy on file for a minimum of 1 year for each coating system installation. 3.2.8 The contractor shall inform both the contracting authority and the coating manufacturer when an application problem that affects the quality of the finished coating
48、 system arises. 3.2.9 If the contractor is inexperienced or unfamiliar with the specified coating system, he/she shall obtain technical assistance from the coating manufacturer. 3.2.10 The contracting authority shall approve all metal repairs to the interior of tank cars prior to initiation of the r
49、epair. AAWDOT requirements for such repairs must be met. 3.2.1 The quality control supervisor and responsible shop supervisory personnel directly involved in the coating application shall be present at the prejob conference scheduled by the contracting authority. 3.2.2 Quality control shall be the responsibility of the contractor. 3.3.1 Technical assistance for application problems shall be provided if requested by the contracting 3.2.3 Authorized shop personnel and representatives authority or the contractor. of the contracting authority shall have suitable access 3.2.1 1
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