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In-Service AST Inspection Report Formal External Inspection of 8,800-Gallon Tank(AST-5) Valley Pacific Petroleum Services,Inc. Page 4 1.9.3. A pneumatic liquid level gauge was installed and visible along the northwestern containment wall. Condor inspectors manually measured the tank volume to compare against installed tank level gauge readings.The manual measurement was 37-inches; and matched the gauge reading of 37-inches. Overfill alarms or vent whistles were not installed. 1.10. Grounding equipment was not installed on AST-5. 1.11. The tank was not equipped with stairways,handrails, or platforms. 1.12. Surface coatings observed on all surfaces of the tank shell, heads, and supports appeared to be in good condition. However, along the top of tank concentrated on the southeast end of the tank multiple instances of paint failure were observed. Maintenance of a tank's protective coating is strongly recommended to prevent external corrosion of the tank shell, pipe-fittings, and piping. 2. Original Shell Thickness of the AST 2.1. Original tank documentation was not provided for review. 2.2. The tank manufacturer was determined by examining the nameplate installed on the tank. 2.3. The tank's nameplate identifies it with an Underwriters' Laboratories (UL) designation. This indicates the tank is manufactured to the UL 142 specification for aboveground storage of flammable liquids. 2.4. According to several ultrasonic thickness (UT)measurements, the original shell thickness is presumed to be approximately 0.250 inches or 1/4-inch rolled steel with an average thickness of 0.260 inches of remaining steel. The original thickness of the tank's heads is presumed to be approximately 0.250 inches or 1/4-inch rolled steel with an average of 0.257 inches of remaining steel. 3. Horizontal ASTs 3.1. Shell plates, welds, and ancillary equipment were inspected for indications of exterior corrosion, buckling, distortion due to stress, cracking, pinholes, and mechanical damage. There were no signs of corrosion or damage on the exterior tank surface. Minor leakage from ancillary piping at both pumps mounted on the tanks topside. 3.1.1. UT measurements and visual inspection of the tank shell revealed no significant internal or exterior corrosion. Refer to the thickness measurements and photographs attached to this report. 3.2. The tank shell was inspected for indications of modifications that may have been made in the past.Brackets and platforms for ancillary tank equipment and piping appear consistent with the original design.No evidence of modification to the original tank was identified. 3.3 INSPECTION SUMMARY The following sections provide a summary of the inspection completed for the tank. UT Measurements Summary To obtain the residual metal thickness readings, a NDT Systems TG110—DL ultrasonic digital thickness meter equipped with a TG-560P transducer was used.The meter has a resolution of±0.001 in(±0.025 mm) intended for use on steel plate and piping materials used in storage tank applications. The meter is capable of collecting readings using a scan mode or single point mode. The meter is factory calibrated(November 23,2016)and proper operation confirmed prior to and during testing using a steel calibration block adhered to the side of the meter. The transducer couplant used was NDT Systems UTG1102 Ultragel II. Field data was recorded onsite.Refer to Figure 1,Attachment A,for a Tank Diagram and UT thickness measurements. r� CONDOR