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Using a Manifold From The I Tank,Pressurize q4. Hol Ze The Tank Cavity To 5 psi Maximum. mamas — t- Stable Walls Open r�anwe ccwseE -.` r.-.` �� In stable soil conditions for 4' M gauge a:gauge i 1r ii �} `� through tbeldiameter ntanks,the �� 1 �� hole must be large enough to allow I 1 1 I I I a minimum of 18"(24"preferred) I II 11 j between adjacent tanks and 18" i (24"preferred)between the tank sides and ends and the banks of the hole. manldtl sKtem(suPPis9 WintarW) 1 I I �� I II` Twelve-foot diameter tanks require Ste #3 _I iD• 24"between tanks and hole sides. P 4•- Minimum l8^ and require 24"between adjacent 12' Minimum 24" tanks. Step#3 If the tanks are mechanically Pressurize the cavity between the inner and outer tank to 5 psi maximum anchored,additional clearance is by opening the manifold valve thereby transferring pressure from the required between tanks(see inner tank. section A7). DO NOT CONNECT THE AIR SUPPLY DIRECTLY TO THE MONITORING FITTING OR ALLOW THE MANIFOLD VALVE TO BE -'.. �_W Unstable Wall s(all size tanks) OPEN DURING STEP#1.Typical air compressors can over Ie pressurize(over 5 psi)the tank cavity between the inner tank and In muck,bog,peat,swamp,or outer tank wall in less than 2 seconds. landfill type areas where the soil is Ste #4: Au Diameters soft or in areas with expansive clay ',%" soils,alarger hole is required to Morntorthe pressure on both the inner tank and cavity between the inner - I I support tanks.In these types of and outer tank for at least 30 minutes.Cover the entire tank outer surface i ., !, ,I I "t. conditions,the holes must be large with a soapy water solution(5 gallons of water with 8 ounces of household I I y enough to allow a minimum of Yz dishwashing detergent).In freezing conditions,substitute l gallon of , I windshield washer solution for l gallon of water.Soap the outer tank and % `.x , I the tank diameter from ends and check for leaks as indicated by bubbles.An outer wall leak detected ' 1 , sides of tanks to hole wail s. before backfilling is simple to repair.Do not backfill a tank with _ ' Unstable soils are defined as those known or suspected leak in the outer wall. re ole.min. soils having less than 750lbs./sq. for unmame walls '..•`•, ` ft.cohesion as calculated from an Inner Wall Test unconfined compression test:or soils with an ultimate bearing Step#5: capacity of less than 3500 tbs./sq.ft.Unstable soils or areas with expan- Close the manifold valve to the cavity between the inner and outer wall. sive clay may require a reinforced concrete slab under tank for support. Release the pressure and vent the primary tank(by opening the air supply valve),but maintain the 5 psi maximum pressure on the cavity For unstable soils with less than 250 lbs./sq.ft.cohesion or with an between the inner and outer walls, ultimate bearing capacity of less than 500lbs./sq.ft.,a filter fabric hole liner is recommended to prevent backfill migration.Refer to Section AS. Step#6: Monitor the air gauge on the tank monitoring fitting for another 30 minutes.but not more than 60 minutes.Longer tests conducted during AS. Filter Fabric changing temperatures or changing cloud cover may distort test results t 1 psi. Itis the responsibility of thetankowneror histechnical representative to In the unlikely event a tank leak is discovered with any of the above determine if filter fabric is appropriate for a specific tank installation.Our tests,call the O/C TANKS Field Service office nearest you to experience indicates that if all the other installation instructions are schedule a tank repair.Do not attempt to repair the tank. carefully followed.the use of filter fabric is not essential. Telephone numbers are listed in Section At 9. Filter fabric preventsthe migration of pea gravel with native soil:it helps to DO NOT EXCEED 5 PSI DURING AIR TEST. maintain the integrity and stability of the backfill material.O/C TANKS recommends the use of filter fabric for the following types of installations: After successfully completing the air test.disconnect and remove the air manifold fittings,hose,and valve. 1.Tidal conditions or areas subjected to frequently changing ground Before backfilling to grade.O/C TANKS recommends a 5 psi air/soap test water levels. on all finished piping connections and unused tank fittings. 2.Unstable soils(muck or landfills). 3.Water conditions with silty soil. Suitable brand name filter fabrics are itemized below.Local filter fabric distributors can be identified by calling the phone numbers listed. Manufacturer Reemay,Inc. Product TYPAR3401 or TYPAR3341 Phone (800)321-6271 Manufacturer Hoechst Celanese Corporation Product TREVIRA S1120(hole depth less than 10'deep) TREVIRA 57125(hole depth greater than 10'deep) Phone (800)845-7597 Manufacturer Phillips Fibers Product SUPAC4NP Phone td00)845-5737 Polyethylene is not considered an effective material to prevent migration ofpea gravel and native soil;it tears and will degrade Ina wet hole environment. Installation Procedure:Line the excavation sides and bottom with filter fabric.Overlap adjoining fabric panels at least 12 inches.Place some backfill on top of the filter fabric in and around the excavation perimeter to hold the fabric in place. In wet hole installations,backfill ballast is necessary to sink and hold the filter fabric to the bottom of the excavation. 3