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5.2.12.3.1.Sloping of tanks may affect accuracy of calibration CAUTION AUTION Do not use metal probes.Failure to follow this caution may 5.2.12.3.2.If a double-wall tank is sloped,the monitor should result in damage to the tank. be at the low and. NOTE:An object like a long wooden shovel handle is a prac- 5.2.13.Use the tops of the ribs to establish longitudinal level. tical choice as a tamping rod. Establish lateral level by placing the level across the top of a fitting or a manway. I CAUTION 5.2.14.If anchor straps are to be used,install them at this Do not strike the tank with the tamping rod.Failure to heed time.See SECTION 8.2. this caution may result in damage to the tank. 5.2.14.1.The locations for anchor straps are marked on tank 5.2.17.Repeat POINTS 5.2.16.and 5.2.16.1.with a second lift ribs by the arrowhead symbol►/(on the tank itself on 4-foot- of approximately 12 inches of primary backfill. diameter tanks). 5.2.18.After the second lift of material has been placed and 5.2.14.2.All marked anchor strap locations must have straps, worked under the tank,bring the backfill to the top of the tank. 5.2.18.1.Place backfill material evenly on opposite sides of CAUTION the tank so that the tank does not shift. Do not place straps between ribs.Failure to property place 5.2.19.If secondary backfill material is to be used on the straps may result in damage to the tank. perimeter of the installation,it must be placed and compacted 5.2.14.3.Place a strap on each marked location and install an- at the same time as the primary backfill material. choring hardware.See SECTION 8. 5.2.20.During the backfilling process,it is good practice to 5.2.14.4.Tighten each anchor strap until it is snug over the rib continue to check tank deflection. (over the tank itself in 4-foot-diameter tanks)but causes no deflection of the tank.Straps must be uniformly tight. CAUTION 5.2.14.5.The elevation of deadmen is critical.If a strap ap- Thoroughly hand tamp backfill to eliminate all voids under pears too short or there is not sufficient adjustment in the turn- the tank.Do not allow the tank to shift during the backfill procedure.If there are voids under the tank and/or the tank buckle to make the strap snug,the tank and/or tank anchors has shifted(and the backfill is above one-quarter(1/4)of the must be repositioned by adding or removing backfill material tank diameter),it may be necessary to remove and reinstall until the straps are properly installed. the tank.Failure to follow this caution may result in damage to the tank and/or property damage. NOTE:Make sure that the minimum bedding thickness of 12 inches has been maintained. 5.2.21.After backfill has been brought to the top of the tank, take another tank diameter measurement. Record it as Meas- 5.2.14.6.After the straps have been Installed and tightened, urement#3 in the Tank Installation Checklist,and determine take a tank diameter measurement to check tank deflection, whether tank deflection is within the allowable limits shown in and record it as Measurement#2 on the Tank Installation TABLE 11-1. Checklist 5.2.22.All UL-labeled tanks,chemical tanks and potable water CAUTION tanks must be air tested after backfill is brought close to the Overdeflection of the tank may result in damage to the tank. top of the tank. 5.2.15.On water/wastewater tanks with bottom fittings,piping 5.2.23. If additional testing(postinstallation testing for air- needs to be installed at this time. testable tanks or optional hydrostatic testing)is to be done, perform those tests now.See SECTION 13 for instructions. 5.2.16.Place approximately 12 inches of primary backfill around the bottom of the tanks between the ribs(if present) SECTI.ON 12 for instructions. Typically,the tank should be ballasted at this time.See and under the end domes. SECTI 5.2.16.1.Use a nonmetal tamping rod long enough toreach 5.2.25.If piping and/or venting needs to be installed,complete beneath the tank to push material under the tank body and this work now.See SECTION 14 for instructions. domes until solid resistance is felt,all voids are filled and the 5.2.26.If containment sumps need to be Installed,do that tank is fully supported.See FIGURE 5-1. now.See SECTION 16 for instructions. - - - =I1 .2.27.Continue to backfill to grade,or to subgra de if rein- R = Wrong I _ forced concrete or asphalt is to be installed. 5.2.28.When the tank has been backfilled to subgrade(but before placement of reinforced concrete or asphalt),take the �� VIII last required tank diameter measurement.Record it as Meas- urement#4 and determine whether tank deflection is within the allowable limits shown in TABLE 11-1. FIGURE 5-1 9