Draft Partial Amendment to the Public Notice Specifying the Detailed Technical Standards for the Regulation of Hazardous Materials

This draft applies to hazardous-material storage facilities equipped with leakage-prevention plates in underground tanks and proposes changes to requirements for their structure, welding, and weld inspection. Bottom plates no more than 9 mm thick may use fillet welds, and gaps that could adversely affect weld strength are prohibited at plate contact surfaces. Side plates must be integrated with the tank side plate and protected against corrosion; at least 50 mm of asphalt sand or similar material must be laid beneath bottom plates. Welds are generally subject to magnetic-particle testing, with penetrant testing permitted where magnetic-particle testing is difficult. Specified underground-tank weld joints may also be tested using leakage-current testing or the alternating-current field measurement method.