ASTM G158-98(R2021) pdf free download

ASTM G158-98(R2021) pdf free download.Standard Guide for Three Methods of Assessing Buried Steel Tanks
1. Scope
1.1 This guide covers procedures to be implemented prior to the application of cathodic protection for evaluating the suit- ability of a tank for upgrading by cathodic protection alone. 1.2 Three procedures are described and identified as Meth- ods A, B, and C. 1.2.1 Method A—Noninvasive with primary emphasis on statistical and electrochemical analysis of external site envi- ronment corrosion data. 1.2.2 Method B—Invasive ultrasonic thickness testing with external corrosion evaluation. 1.2.3 Method C—Invasive permanently recorded visual in- spection and evaluation including external corrosion assess- ment. 1.3 This guide presents the methodology and the procedures utilizing site and tank specific data for determining a tank’s condition and the suitability for such tanks to be upgraded with cathodic protection. 1.4 The tank’s condition shall be assessed using Method A, B, or C. Prior to assessing the tank, a preliminary site survey shall be performed pursuant to Section 8 and the tank shall be tightness tested pursuant to 5.2 to establish that the tank is not leaking. 1.5 While this guide provides minimum procedures for assessing a tank’s condition, this guide does not provide minimum installation procedures or requirements for upgrades of the tank by cathodic protection. 1.6 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appro- priate safety, health, and environmental practices and deter- mine the applicability ofregulatory limitations prior to use. 1.8 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
3. Terminology
3.1 Definitions ofTerms Specific to This Standard: 3.1.1 buried—to be placed in the ground and covered with earth. 3.1.2 cathodic protection—an applied technique to prevent further corrosion of a metal surface by making that surface the cathode of an electrochemical cell. For example, a tank system can be cathodically protected through the application of either galvanic anodes or impressed current. 3.1.3 corrosion specialist/cathodic protection specialist—a competent person who by reason of knowledge of the physical sciences and the principles of engineering and mathematics, acquired by education and related practical experience, is qualified to engage in the practice of corrosion control on buried or submerged metallic piping systems and metallic tanks. Such persons shall be registered professional engineers or persons recognized as corrosion specialists or cathodic protection specialists by NACE, if their professional activities include suitable experiences in external corrosion control on buried or submerged metallic piping and tanks.3.1.4 corrosion technician—a person possessing basic knowledge of corrosion and corrosion control, who is capable ofperforming routine, well defined work under the supervision of the corrosion specialist/cathodic protection specialist. 3.1.5 invasive procedure—a method of determining the corrosion status of a tank by assessing the tank from the inside as part of the upgrade procedure. Further, for the purposes of this guide, it does not require manned entry into the tank. (See non-invasive.) 3.1.6 limitations—The user of this guide is encouraged to review any available third party verification information pro- vided as part of the vendor selection process. 3.1.7 noninvasive procedure—a method of determining the corrosion status of a tank from the characteristics of its surroundings with minimal entry into the tank. Further, for the purposes of this guide, it does not require manned entry into the tank. (See invasive.) 3.1.8 pH—the numerical value of the negative logarithm of the hydrogen ion concentration in moles per litre in an electrolyte.