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American BiodieselSilo S-1 Stockton,CA g v_= Out of Service Inspection 4.2 Silo Nozzles A visual inspection and ultrasonic examination of all accessible nozzles and manways was conducted to evaluate the current condition of each nozzle. Visual inspection of each nozzle included evaluation of the internal and external neck, all attachment welds, and flange faces. Areas of limited inspection would include nozzles with internal piping attached and nozzles with valves or blinds covering flange faces. All nozzles and manways were visually inspected internally. Due to the external foam insulation, the external portions of the nozzle necks were not accessible for visual inspection. The internal attachments welds of the manway and all nozzles were found to be in satisfactory condition. No visible signs of defects or cracks were found. The attachment welds have no significant corrosion or deterioration. The internal pipe necks of the nozzles and manway were cleaned to remove as much of the product build up and scale as possible. The manway and nozzle necks were also found to be in good condition, with no concerns. It is recommended that all nozzles and the manway be thoroughly cleaned to remove all scale and product build up prior to placing the tank in service. All nozzles and manways were Ut'd by recording four readings on the top, bottom and both sides of each neck. The UT survey of the manway and nozzles did not reveal any abnormal deviations from nominal pipe wall thicknesses. Section 8.2 details all data from the nozzle UT exam. 4.3 Top Head Plate The top head plate on Silo S-1 has a nominal thickness of 0.250 inches. This head plate was ultrasonically examined to determine the average remaining thickness. A total of 20 UT readings were obtained. This UT survey revealed the remaining thickness to be from a low of 0.220 inches to a high of 0.248 inches. The top head plate was also visually inspected. This plate was found to be in similar condition as the upper 3 -4 feet of the silo shell. General pit type corrosion is present throughout the entire plate, with a stronger presence around the manway and nozzles. Pit depths on this plate also ranged from 0.010" — 0.050". Again, the extent of this corrosion was not found severe enough to be detrimental to continued service or to warrant repairs. Inspectors Signature: _ Gerald Al.len API 653 Certification No. 28542 Report Date Petroleum&Refractory, Inc. Page 7 of 21 March 6,2007 TankReporter 13.91