ASTM International

Standard Guide for Three Methods of Assessing Buried Steel Tanks
 N G158

Annotation

This guide covers procedures to be implemented prior to the application of cathodic protection for evaluating the suitability of a tank for upgrading by cathodic protection alone.

Three procedures are described and identified as Methods A, B, and C.

Method A - Noninvasive with primary emphasis on statistical and electrochemical analysis of external site environment corrosion data.

Method B - Invasive ultrasonic thickness testing with external corrosion evaluation.

Method C - Invasive permanently recorded visual inspection and evaluation including external corrosion assessment.

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.

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.

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.

The values stated in inch-pound units are to be regarded as the standard. The SI units given in parentheses are provided for information only.

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 appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.