4.1 This test method is designed to detect existing discontinuities in the glass coating of glassed steel equipment while maintaining a voltage low enough as to be unlikely to cause breakdown of the coating. The test is adaptable for manufacturing inspection in the processing of equipment and for field use to find existing defects which can be “plugged” or repaired before serious damage is done to the equipment. As a means of positive detection, it is applicable to process studies, quality control, or specification.

1.1 This test method covers the detection of discontinuities in the glass coating of glassed steel equipment where such discontinuities would result in early failure due to the attack of the chemical contents of the vessel on the metal substrate. It is applicable to (1) provide a manufacturing and inspection test of glassed-steel equipment designed for relatively mild, low-temperature corrosive service, and (2) the field testing of similar equipment used in more severely corrosive environment.

Note 1: A manufacturing test method for the latter type of equipment is described in Test Method C537.

1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.3 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.