Issue Date: March 31, 2006

Revision Date:  July 27, 2009

Simmons Corp.

(originally listed as Caldwell Systems Corp.)

Simmons/Caldwell Tank Manager Monitoring Systems with CITLDS
Ultrasonic Probe)

(Continuous Automatic Tank Gauging)


Leak rate of 0.2 gph with PD = 100% and PFA = 0%.

Leak Threshold

Not applicable for qualitative methods.
Method is qualitative and reports a result of “pass” or “fail”.


Gasoline, diesel, aviation fuel, solvents, waste oil, fuel oil #4, water.

Tank Capacity

Maximum of 18,000 gallons for single tanks
Maximum of 54,000 gallons cumulative capacity for manifolded tank systems.
Minimum product level required to conduct a test is 20 inches.


Monthly maximum of 147,136 gallons.

Waiting Time

Minimum of 4 hours stabilization time is allowed between delivery and data collection.

Test Period

Data collection time ranges from 3 to 27 days.
Data sampling frequency is every 1 minute.
System collects data at naturally occurring product levels without interfering with normal tank operation, and discards data from unstable periods when system performs test.


Average for product is determined by a minimum of 5 sensors.

Water Sensor

Must be used to detect water ingress.
Minimum detectable water level in the tank is 0.736 inch.
Minimum detectable change in water level is 0.031 inch.


Probe must be checked annually and, if necessary, calibrated in accordance with manufacturer's instructions.  


Evaluated using both single and manifolded tank systems with probes in each tank.
For valid monthly testing, a conclusive test report must be produced for each tank every month.
System warns operator if there are no “passing” tests completed during the month.
For very active tanks, a tank shut down may become necessary in order for the system to collect enough quiet-time data for a test.
Constant and variable leaks were mathematically induced into tight tank test records, which were collected by systems installed at various active tank sites.
The database for evaluation of the system included sites with vapor recovery and blending dispensers.
Tanks used in this evaluation contained gasoline and diesel.


Simmons Corp.

Evaluator:  Ken Wilcox Associates

106 E. Main Street

Tel:  (816) 443-2494

Richardson, TX 75081-3327

Date of Evaluation:  04/08/05

Tel:  (800) 848-8378





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