Laserfiche WebLink
4 <br /> Sent by: STRUCTURES LAB,CSULB 562 985 4406 03/31/99 12:19 ,lob 750 Page 3/5 <br /> proper cure and/or degradation of the surface resin. First,the acetone test was perfonned in <br /> which a cloth wetted with acetone was rubbed on the inner surface of the tank at 3 or 4 locations <br /> as prescribed by ASTM. No tackiness was evident in any of these locations. In addition to <br /> acetone,a more severe chemical was applied to the inner surface consisting of 1/3 iso-octan, 113 <br /> 14)lnene,and 1013 ethyl alcohol by volume. Tltis chemical is one of the standard mixtures <br /> prescribed by Underwriters Laboratories in the evaluation of fiberglass laminates for <br /> underground tanks. As with acetone,no sensitivity of the inner surface to this chemical was <br /> observed. Therefore,it can be concluded that the inner surface of the tank has not been <br /> chemically degraded by the storage of gasoline. Further evidence of this fact is the shiny <br /> appearance of the inner surface of the tank shell and the end domes. Therefore,the West tank is <br /> structurally sound and has experienced virtually no chemical degradation due to the storage of <br /> the gasoline. <br /> For the Last tank, my measurements of the diameter were very similar to those of Fluid <br /> Containment(this data has also been given to Mr. Wilson for his analysis). The measured <br /> diameters are all within 1/2 in.of the original manufacturing diameter,and thus well within the <br /> 1%requirement, Regarding visual inspection for the Last tank,the same observations were <br /> made as for the West tank. Under chemical exposure of acetone, and the more severe mixture of <br /> toluene, iso-octane,and ethyl alcohol,there was no tackiness or sensitivity of-the inner surface of <br /> the tank from both of these chemicals, The inner surface still has a shiny appearance which is a <br /> clear indication of little or no chemical degradation, Therefore,the Gast tank is structurally <br /> sound and has experienced little or no chemical degradation Crom the stored gasoline. <br /> In addition to the above conclusions,minor alterations recommended below are designed <br /> to ernlrance the performance of the tank over an extended period of time. <br /> I The interior center seam for both tanks should be provided with a bond which is currently <br /> lacking. <br /> 2. The bonds over plates at the bottom of both tanks should he enhanced with additional <br /> layers of mat. However.close inspection of these areas indicated that no degradation or <br /> cracking has been caused by past usageof'dipsticks. <br /> 3. At the interface between the dome and the shell,a relatively rough transition surface is <br /> evident for both tanks and at both domes of each tank. Close visual inspection of this <br /> region indicated no chemical or physical degradation. However,it is my opinion that it <br /> would be prudent to apply one or two layers of mat approximately 6 in. wide billowed by <br /> one laver of C-ved. <br /> Recently, it has been customary for Fluid Containment to perl'onn Ite!�at... above <br /> when entering any single wall tanks. Item No.3 is a suggestion which y ,c*1 , r <br /> may not choose to adopt. If you have any questions,please call me at -go <br /> 4�G✓! t, ld <br /> M =6154 <br /> ts0'd 0939 b89 915 '00 S.l3f1GOUd ODUV VS i =80 66-I O-ado <br />