1、Designation: G 158 98 (Reapproved 2004)Standard Guide forThree Methods of Assessing Buried Steel Tanks1This standard is issued under the fixed designation G 158; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revi
2、sion. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.INTRODUCTIONThe purpose of this guide is to provide three methods of inspecting and assessing buried steeltank(s) for corrosion damage and
3、 determining the suitability of these tanks prior to application ofcathodic protection.1. Scope1.1 This guide covers procedures to be implemented prior tothe application of cathodic protection for evaluating the suit-ability of a tank for upgrading by cathodic protection alone.1.2 Three procedures a
4、re described and identified as Meth-ods A, B, and C.1.2.1 Method ANoninvasive with primary emphasis onstatistical and electrochemical analysis of external site envi-ronment corrosion data.1.2.2 Method BInvasive ultrasonic thickness testing withexternal corrosion evaluation.1.2.3 Method CInvasive per
5、manently recorded visual in-spection and evaluation including external corrosion assess-ment.1.3 This guide presents the methodology and the proceduresutilizing site and tank specific data for determining a tankscondition and the suitability for such tanks to be upgraded withcathodic protection.1.4
6、The tanks condition shall be assessed using Method A,B, or C. Prior to assessing the tank, a preliminary site surveyshall be performed pursuant to Section 8 and the tank shall betightness tested pursuant to 5.2 to establish that the tank is notleaking.1.5 While this guide provides minimum procedures
7、 forassessing a tanks condition, this guide does not provideminimum installation procedures or requirements for upgradesof the tank by cathodic protection.1.6 The values stated in inch-pound units are to be regardedas the standard. The SI units given in parentheses are providedfor information only.1
8、.7 This standard does not purport to address all of thesafety concerns, if any, associated with its use. 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.2. Referenced Do
9、cuments2.1 The most recent version of the following documentsshould be consulted as references by those using this guide:2.2 ASTM Standards:2D 2216 Test Methods for a Laboratory Determination ofWater (Moisture) Content of Soil and RockE 114 Practice for Ultrasonic Pulse-Echo Straight-BeamExamination
10、 by the Contact MethodE 797 Practice for Measuring Thickness by Manual Ultra-sonic Pulse-Echo Contact MethodE 1323 Guide for Evaluating Laboratory MeasurementPractices and the Statistical Analysis of the Resulting DataE 1526 Practice for Evaluating the Performance of ReleaseDetection Systems for Und
11、erground Storage Tank Sys-tems3G 51 Test Method for pH of Soil for Use in CorrosionTestingG 57 Test Methods for Field Measurement of Soil Resistiv-ity Using the Wenner Four-Electrode Method2.3 American Society for Nondestructive Testing Stan-dard:4ASNT SNT-TC-1A Personnel Qualification and Certifica
12、-tion in Nondestructive Testing1This guide is under the jurisdiction of ASTM Committee G01 on Corrosion ofMetals and is the direct responsibility of Subcommittee G01.10 on Corrosion inSoils.Current edition approved May 1, 2004. Published May 2004. Originallyapproved in 1998. Last previous edition ap
13、proved in 1998 as G 158 98.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.4Available from The Ame
14、rican Society for Nondestructive Testing (ASNT), P.O.Box 28518, 1711 Arlingate Ln., Columbus, OH 43228-0518.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.2.4 NACE International Standards:5RP-0169 Standard Recommended Practice-Contr
15、ol on Ex-ternal Corrosion on Underground or Submerged MetallicPiping SystemsRP-0187 Standard Recommended Practice-Design Consid-erations for Corrosion Control of Reinforcing Steel inConcreteRP-0285 Standard Recommended Practice-Corrosion Con-trol of Underground Storage Tank Systems by CathodicProtec
16、tion2.5 Environmental Protection Agency Methods:6EPA SW 846 Test Methods for Evaluating Solid WasteEPA 371.1 Measurement of Sulfate Reducing Bacteria2.6 National Fire Protection Association (NFPA)7NFPA 329 Recommended Practice for Handling Under-ground Releases of Flammable and Combustible Liquids2.
17、7 Underwriters Laboratories Inc.8UL 58 Steel Underground Tanks for Flammable and Com-bustible Liquids3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 buriedto be placed in the ground and covered withearth.3.1.2 cathodic protectionan applied technique to preventfurther corrosion
18、 of a metal surface by making that surface thecathode of an electrochemical cell. For example, a tank systemcan be cathodically protected through the application of eithergalvanic anodes or impressed current.3.1.3 corrosion specialist/cathodic protection specialistacompetent person who by reason of
19、knowledge of the physicalsciences and the principles of engineering and mathematics,acquired by education and related practical experience, isqualified to engage in the practice of corrosion control onburied or submerged metallic piping systems and metallictanks. Such persons shall be registered pro
20、fessional engineersor persons recognized as corrosion specialists or cathodicprotection specialists by NACE, if their professional activitiesinclude suitable experiences in external corrosion control onburied or submerged metallic piping and tanks.3.1.4 corrosion techniciana person possessing basick
21、nowledge of corrosion and corrosion control, who is capableof performing routine, well defined work under the supervisionof the corrosion specialist/cathodic protection specialist.3.1.5 invasive procedurea method of determining thecorrosion status of a tank by assessing the tank from the insideas pa
22、rt of the upgrade procedure. Further, for the purposes ofthis guide, it does not require manned entry into the tank. (Seenon-invasive.)3.1.6 noninvasive procedurea method of determining thecorrosion status of a tank from the characteristics of itssurroundings with minimal entry into the tank. Furthe
23、r, for thepurposes of this guide, it does not require manned entry intothe tank. (See invasive.)3.1.7 pHthe numerical value of the negative logarithm ofthe hydrogen ion concentration in moles per litre in anelectrolyte.3.1.8 tank tightness testa method capable of detecting a0.1 gal/h leak rate, whil
24、e accounting for any applicable effectsof thermal expansion or contraction of the product, of vaporpockets, of tank deformation, of evaporation or condensation,and of the location of the water table. The method must becapable of detecting a 0.1 gal/h leak rate with a probability ofdetection of at le
25、ast 0.95 and a probability of false alarm of atmost 0.05 or in accordance with NFPA 329.3.1.9 underground storage tank (UST)any one or combi-nation of tanks (including connected underground piping), thevolume of which is 10 % or more beneath the surface of theground.3.1.10 upgradethe addition to or
26、retrofit of UST systemsusing approaches including, but not limited to, cathodic pro-tection to improve the ability of a UST system to prevent arelease.3.1.11 unconditional probability of corrosion failuretheprobability of corrosion failure which includes a determinationof whether localized, pitting,
27、 or general corrosion is occurring.3.1.12 USTsee underground storage tank (see 3.1.9).3.1.13 redox potentialpotential of platinized platinumelectrode in a redox environment (reversible system). Thevalue of redox potential depends on whether the system is inthe oxidized, partially oxidized, partially
28、 reduced, or reducedstate.3.2 limitationsThe user of this guide is encouraged toreview any available third party verification information pro-vided as part of the vendor selection process.3.3 vendor provided informationThe user is referred toAnnex A1 for a specific form and format of information whi
29、chmust be provided by a vendor. This information consists ofhistoric performance data on a method and is mandated as partof the guide.4. Significance and Use4.1 This guide provides three methods for determining thesuitability of a buried steel tank to be upgraded with cathodicprotection.4.2 This gui
30、de may be used to assess any UST, includingnon-regulated USTs.4.3 This guide provides three alternative methods but doesnot recommend any specific method or application. Theresponsibility for selection of a method rests with the user.4.4 This guide has specific requirements for vendor pro-vided info
31、rmation which should be requested and reviewed bythe user.5. Permits, Plans and Tank Leak Testing5.1 Prior to engaging in any activities relating to thealteration, repair, or upgrade of any UST system, consult allnecessary authorities to obtain any required permits.5.2 Tank Leak Testing:5Available f
32、rom National Association of Corrosion Engineers (NACE), 1440South Creek Dr., Houston, TX 77084-4906.6Available from Underwriters Laboratories (UL), Corporate Progress, 333Pfingsten Rd., Northbrook, IL 60062.7Available from US Environmental Protection Agency, Office of UndergroundStorage Tanks, 401 “
33、M” St. SW, Washington, DC 20460.8Available from National Fire Protection Association (NFPA), 1 BatterymarchPark, Quincy, MA 02269-9101.G 158 98 (2004)25.2.1 To establish that tanks are not leaking prior to assess-ment, they shall be assessed by a leak detection system. Thisleak detection assessment
34、alone is not sufficient to determinethat a tank is suitable for upgrading with cathodic protectionunder this guide.5.2.2 A tightness test or another release detection system inaccordance with NFPA 329 shall be used. Any release detectionmust be capable of detecting a leak from any portion of thetank
35、 that routinely contains product, and be independentlyevaluated and certified in accordance with Practice E 1526 orthe equivalent. Leak detection results shall be provided to thecorrosion specialist/cathodic protection specialist.5.2.3 This testing shall be accomplished within six monthsprior to per
36、forming any of the assessment procedures.6. Required Approvals and Certifications6.1 The corrosion assessment work carried out under thisguide shall be performed under the responsible direction of acorrosion specialist/cathodic protection specialist as defined in3.1.3.6.2 The corrosion specialist/ca
37、thodic protection specialistshall certify to the tank owner or operator that the personnelperforming the assessment work on the tank are knowledgeableof all the applicable procedures in this guide.6.3 The corrosion specialist/cathodic protection specialistshall certify to the tank owner or operator
38、that all work wasperformed in strict accordance with this guide.7. General Safety Requirements7.1 All personnel shall comply with applicable federal,state, and local health and safety codes and regulations.8. Preliminary Site Survey8.1 A corrosion technician, under the responsible directionof the co
39、rrosion specialist/cathodic protection specialist, shallobtain tank site specific information as appropriate to themethod of assessment to be used.8.1.1 Facility Information:8.1.1.1 Address or location, and8.1.1.2 Name and telephone number of owner and operatorcontact personnel.8.1.2 Tank and Piping
40、 Details:8.1.2.1 Number and capacity,8.1.2.2 Location and dimensions,8.1.2.3 Age,8.1.2.4 Material of construction,8.1.2.5 Electrical isolation,8.1.2.6 Type of product stored,8.1.2.7 Names of site contact personnel,8.1.2.8 Backfill material,8.1.2.9 Coatings and linings,8.1.2.10 Leak history,8.1.2.11
41、Repair history,8.1.2.12 Site plans,8.1.2.13 Installation specifications,8.1.2.14 Tank excavation liners, and8.1.2.15 As-built drawings.8.1.3 Information Not in the Immediate Vicinity of theTanksThe presence of the following items, that are externalto the tank area, shall be investigated and included
42、 as appro-priate to the method of assessment of the suitability of tanks forupgrading with cathodic protection:8.1.3.1 Stray dc current sources,8.1.3.2 Existing cathodic protection systems,8.1.3.3 Steel product and vent piping and fittings, and8.1.3.4 Adjacent subsurface metallic/steel-reinforced co
43、n-crete structures.8.2 Preliminary EvaluationPrior to assessing the tank, apreliminary site survey must be performed pursuant to Section8 and a tightness test must be performed pursuant to 5.2 toestablish that the tank is not leaking.9. Method ANoninvasive with Primary Emphasis onStatistical and Ele
44、ctrochemical Analysis of ExternalSite Environment Corrosion Data (1,2)9.1 Field and Laboratory TestingNoninvasive with Pri-mary Emphasis on Statistical and Electrochemical Analysis ofExternal Site Environment Corrosion Data.9.1.1 Tests shall be conducted by, or as directed by acorrosion specialist/c
45、athodic protection specialist.9.1.2 Field Testing ProceduresTests to be performed shallinclude, but are not limited to, the following:9.1.2.1 Stray CurrentsPerform tests to detect the presenceof stray currents at each tank site. This test shall consist ofmeasuring structure-to-soil potentials at rig
46、ht angles at aminimum of two locations within the tank facilities andobserving the measurements for not less than2hatatimewhen such influences are most likely to occur. The monitorshall consist of a field data acquisition unit, with a minimum of10-MV input impedance, used in conjunction with a stabl
47、ereference cell(s) placed in contact with the soil in the vicinityof the tank. The instrument shall measure and store structure-to-electrolyte potential (voltage) data at least every 5 s through-out the entire duration of field investigation at the site or for 2h, whichever is greater. If variations
48、 of 650 mV or greater aremeasured during the test period, make 24-h recording measure-ments to confirm stray current effects.9.1.2.2 Tank Information:(a) Locate all tanks and confirm materials of construction,age, capacity, and dimensions. Produce detailed site sketchesdescribing the layout of the U
49、ST system and above gradepertinent details for each site.(b) Determine the presence and extent of internal corrosionimmediately below the fill riser. If the depth of corrosionpenetration in the tank shell exceeds 50 % of the tank wallthickness, the UST shall be declared to have failed the test andthe procedure.(c) Determine if the tanks and piping are electricallycontinuous.9.1.2.3 Bore Hole Tests:(a) Determine locations for soil borings in the field. Maketwo test holes for each tank excavation zone with four or fewertanks. For tank excavation zones with mo
