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 Issue Date: April 18, 1997 
Revision Date: May 23, 2011 
 
Tidel
Engineering, Inc. 
Tidel
Environmental Monitoring System, EMS 4000 
(Ultrasonic Probe #312-9001) 
AUTOMATIC TANK GAUGING METHOD 
Tidel Engineering, Inc. no longer 
manufactures or supports the use of this method. 
  
    | Certification | 
    Leak rate of 0.2
      gph with PD = 99.9% and PFA = 0.1%.  | 
   
  
    | Leak
      Threshold | 
    0.1 gph for leak
      rate of 0.2 gph.  
      A tank system should not be declared tight if the test result indicates a
      loss or gain that equals or exceeds this threshold. | 
   
  
    | Applicability | 
    Gasoline, diesel,
      aviation fuel, fuel oil #4.  | 
   
  
    | Tank
      Capacity | 
    Maximum of 15,000
      gallons.  
      Tank must be between 50 and 95% full. | 
   
  
    | Waiting
      Time | 
    Minimum of 2
      hours, 23 minutes between delivery and testing.  
      Minimum of 15 minutes between dispensing and testing.  
      There must be no delivery during waiting time. | 
   
  
    | Test
      Period | 
    Minimum of 2
      hours for leak rate of 0.2 gph.  
      Test data are acquired and recorded by the microprocessor contained within
      the EMS console.  
      Leak rate is calculated from data determined to be valid by statistical
      analysis.  
      There must be no dispensing or delivery during test. | 
   
  
    | Temperature | 
    Average for
      product is determined from the measurement of the change in the speed of
      sound. | 
   
  
    | Water
      Sensor | 
    Must be used to
      detect water ingress.  
      Minimum detectable water level in the tank is 1.045 inches.  
      Minimum detectable water level change is 0.053 inch. | 
   
  
    | Calibration | 
    Gain adjustment
      on probe must be checked annually and, if necessary, calibrated in
      accordance with manufacturer's instructions. | 
   
  
    | Comments | 
    Not evaluated 
    using manifolded tank systems. Therefore, this certification is only 
    applicable when there is a probe used in each tank and the siphon is broken 
    during testing.  
      Tests only portion of tank containing product.  
      As product level is lowered, leak rate in a leaking tank decreases (due to
      lower head pressure).  
      Consistent testing at low levels could allow a leak to remain
      undetected.  
      EPA leak detection regulations require testing of the portion of the tank
      system which routinely contains product.  
      This is a shorter version of model #312-9000. | 
   
 
  
  
    | 
       Tidel Engineering, Inc.
      
      
       
     | 
    
       Evaluator: 
      Ken Wilcox Associates
      
      
       
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    | 
       
		
		2025 West Beltline Road, #114  | 
    
       Tel: 
      (816) 443-2494
      
      
       
     | 
   
  
    | 
       Carrollton,
      TX  75006
      
      
      
      
       
     | 
    
     Date of Evaluation: 
      
      03/16/95
       
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    | 
       Tel: 
      (800) 678-7577
      
      
       
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