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Continuous Leak• Hydrostatic Tank Monitor TyPlcal Tank Test Monitoring Normal Io-Ssmlce Condition Using the Hydrostatic bnk Monitor TAPE MEASURE The installing contractor fills CONCRETE IC PAD the cavity between the inner and outer tank walls with water. An antifreeze mixture is required for cold climate areas. RISER PIPE Fluid is added in the Fiberglas® reservoir (which is surface ELECTRONIC mounted on the tank top) RESERVOIR until the reservoir is 2/3 full. SENSOIRO IO pyry 1 RESERVOIR MONITORINGvYl� 41 A stable liquid level in the `Ilya ^Rf "r RIND yt�l reservoir indicates that both DOUBLE MALL TANK ,... Fw tn.,...n'l,.eu..m. —I,tal and m..'s .mon l,oun lltM m..x,rW j the inner and outer walls of I...I.a.,at*urs AarsmaaM.u.voMn r n Inam•e»nnk P.....m.m the double-wall tank are "tight" The liquid level in the reservoir will fluctuate as the When the Hydrostatic Tank 4. Using a tape measure, temperature of the incoming Monitor is used as a precision measure and record the stored product changes. The tank test, it offers unique fea- liquid level in the riser pipe. reservoir is designed to pro- tures and benefits for the tank vide adequate capacity for owner: 5. After four more hours, if the normal thermal expansion measured liquid level in the and contraction. a Tests both the inner and riser pipe is within 1" of the outer tank wall to minimize original recorded liquid In the unlikely event of a tank potential liability due to leaks. level, the tank' passes the leak, the liquid will totally drain test criteria for leaks less from the Fiberglas reservoir. If a The tank can remain in than 0.05 gallons per hour the leak is in the primary tank, service during the tank test; with at least a 95% proba- the reservoir monitoring fluid fewer operating interruptions bility of leak detection and will drain into the primary tank. minimize the hidden costs less than 5% probability of Conventional water-finding associated with other tank a false alarm. paste can detect the presence testing methods. of reservoir fluid in the bottom 6. After completing the tank of the primary tank. a Continuously tests the tank test, remove the added for leaks to minimize poten- liquid from the reservoir The reservoir liquid level can tial liability due to leaks. and reservoir riser pipe and be monitored periodically by replace the reservoir sensor. using a dipstick or continuously Summary of the Precision by using optional electronic Test Procedure 'Tanks 12,000 gallon capacity equipment from O/C TANKS or The tank tightness test is or less. Specific testing pro- another monitoring equipment simple and easy to perform: cedures for all tank capaci- vendor. ties, other leak rates, and 1. Before initiating the test, high groundwater conditions An annual inspection of the wait 24 hours following a are detailed in O/C TANKS' reservoir liquid level is recom- product delivery to allow Technical Report #642-1 and mended. Refill the reservoir the tank to reach tempera- the Continuous Precision to maintain the liquid level at ture stability. Product dis- Tank Testing catalog (O/C approximately six inches. pensing may continue prior publication 3-PE-15552). to and during the tank test. Precision Tank Testing In the unlikely event the 2. Remove the reservoir reservoir drains, a simple sensor from the riser pipe testing sequence can confirm for the duration of the test. and quantify the tank leak. It Fill the reservoir with water also can screen for potential (antifreeze in cold climates) false alarms.Although unlikely, through the riser pipe until the reservoir may drain from a the liquid level is about II . false alarm condition, such as 12" above the top of the escaping trapped air or extreme reservoir. temperature changes(a change of over 65°F) of the delivered 3. Wait three hours after filling product. the reservoir riser pipe (4" diameter) to allow for tank geometry changes.