LT-100
Leak detection in pipelines at bulk fuel facilities & truck/railcar loading racks
The Vista LT-100 is a self- contained leak detection system for the underground piping typical of truck and railcar loading-rack facilities. It comprises both hardware (a physical apparatus connected to the pipeline) and software (the computer program that runs a test).
The LT-100 is independently certified and is listed by the NWGLDEas complying with all EPA protocols.
When the volume of fuel is less than 3400 gallons—roughly 1300 feet of 8- inch-diameter pipe—the LT-100 can reliably detect leaks as small as 0.1 gallon per hour. When the volume is greater than 3400 gallons it can detect a leak equivalent in size to 0.0021% of the total volume per hour. Most importantly, through its algorithm for temperature compensation, the LT-100 overcomes some of the major deficiencies of conventional pressure tests.
The LT-100 is a computer- controlled, fully automatic system. All data are acquired and processed electronically. As shown in the schematic diagram at right, the LT-100 sensor unit consists of (1) a measurement cylinder (Tank 1); (2) a storage cylinder (Tank 2); (3) a differential pressure sensor to measure level changes in the measurement cylinder electronically; (4) a pump for transferring fuel from the measurement cylinder or storage cylinder to the line in order to increase line pressure to a specified level; and (5) two pressure relief valves and a bypass valve for removing fuel from the line and adding it to the measurement cylinder or storage cylinder in order to decrease the pressure in the line to a specified level. When combined, the pump and the pressure relief valves can be used to maintain a constant pressure in the line at a specified level. The size of the cylinders is determined by the capacity of the largest pipeline segment that will be tested at a given site.
The storage cylinder is normally used to set or change the overall pressure in the line. (Pressure can also be set or changed with the pressure management system used to operate the line or by adding or removing fuel from a nearby tank, tanker truck, or pipeline.) The measurement cylinder is normally used to maintain constant pressure during a test and to make the volume measurements required during the test. A test can be conducted with the measurement cylinder alone if there is no need for the extra storage capacity that Tank 2 provides. The pump and pressure-relief-valve system are used to adjust and maintain a constant pressure in the line. As shown by the valves on the "ladder," the system can be operated at three pressures: a high pressure, a low pressure, and atmospheric pressure (by means of the bypass valve). The high- and low-pressure relief valves can be set to operate at any desired pressure. Finally, a pressure relief valve and an overfill alarm in each cylinder ensure safe operation of the system.
