Tank testing helps determine the integrity of your tank, and whether or not it’s safe to continue using. If the tank isn’t safe, CommTank can recommend repairs or remove the tank so it doesn’t cause any further damage to the building, soil and groundwater. Typically issues that arise after tank testing are related to the fill, vent, and supply piping. Corrosion to the threads of the piping, or loosening of the pipes over time, can produce a failed result during the test. Damaged sensors and gauges can also affect the test and need to be replaced. CommTank can repair these issues quickly so that your fuel system is ready to be brought back on line with little or no down time.
Since testing cannot predict what will happen to the tank next year, next month or even the next day, you may want to consider replacing an underground tank with an aboveground tank. If you do choose tank testing, CommTank has years of experience in both underground tank testing and aboveground tank testing in Massachusetts. Following a proven approach perfected over the years, we test tanks and lines using ultrasonic tests, non-volumetric tests, pressure or vacuum tests, or soil or water tests below the tank. We also can locate a tank or pipe leak by using Helium or Hydrogen as a tracer gas.
Underground Storage Tank Testing
The most common tests for underground storage tank testing in Massachusetts are pressure testing, vacuum testing, and subsurface investigation.
Vacuum testing is the safest method for testing tanks that are currently in service. Fluid in a tank exerts pressure on the sidewalls of the tank so adding extra pressure could exceed the manufactures limit or exacerbate an existing problem. Vacuum testing is safe because it offsets the pressure exerted by the fuel on the bottom of the tank. Once the vacuum creates an equalization of pressure, a failing tank will lose vacuum and take in air or water from the area outside the tank and a sound tank will hold vacuum. CommTank uses the EZY 3 Locator Plus system, which is a non-volumetric acoustical system. The EZY 3 Locator Plus consists of a microphone placed in the ullage of the underground tank. The microphone is connected to the acoustic signal processor and to a head set enabling the test operator to listen to the acoustic sounds in the tank. Using the motor/blower assembly a slight negative pressure is applied to the tank system, air and/or water will be drawn into the tank if a leak exists. These acoustic signals are recognized by a certified testing operator and characterized as an ullage portion leak/hiss sound or product portion leak/bubble sound. If ground water is above the tank bottom, the conductive water sensor will be used.
The issues that limit volumetric and mass measurement technology have no impact on acoustic based systems.
Benefits of the EZY 3 Locator Plus system compared to other test systems:
- Does not require a specific capacity during test – the tank can be empty or 99% full
- Does not require a temperature stabilization period
- Tests the tank, vent piping, fuel supply and return lines
- Meets or exceeds U.S. EPA accuracy requirements for tank testing
- Produces test results in one hour
Estabrook, Inc. has certified CommTank’s technicians to operate this test system and recertifies our testers every 2 years. The tank test equipment is calibrated yearly as required by the manufacturer.
What steps are required for a tank tightness test?
- A monitoring well is checked for groundwater prior to testing to determine the vacuum level required for the test.
- The testing equipment is temporarily installed in the tank, usually through the fill pipe.
- The fuel supply and return lines are disconnected and capped.
- Access to the tank’s vent pipe is important because the vent line will be plugged with an expandable test plug.
- The tank will be taken out of service during the test for a minimum of 30 minutes.
What are the EPA regulatory requirements for tank tightness testing?
- Tightness tests must be performed periodically. New UST systems (those installed after December 1988) must have tank tightness tests every 5 years for 10 years following installation. In most cases, existing UST systems (those installed before December 1988) that have spill, overfill, and corrosion protection must have tank tightness tests every 5 years for 10 years following upgrade.
- After the applicable time period noted above, you must have a monitoring method that can be performed at least once per month.
A subsurface investigation can be used in conjunction with other tank testing methods and requires drilling or coring into the soil around the tank. The soil samples are then analyzed for the presence of petroleum constituents. The test is an effective way to determine the condition of the soil, but it cannot determine the condition of the tank. Also, the test is not accurate enough to pinpoint the location of a leak in the tank or to indicate if there’s contamination in the soil directly beneath it. Monitoring wells are important for all tank test methods because a monitoring well will show the level of groundwater during the test. Make sure the company that tests your tank uses a monitoring well because all test methods require one.
A tank submerged in water could show a false positive if the operator does not compensate for the external water pressure.
Pressure testing is used only on new tanks prior to filling to ensure they meet the manufacturer’s specification and that there was no damage done to the tank during transportation and installation. The required pressure is greater than 3 pounds per square inch but less than 5 pounds per square inch for the tank and a minimum of 50 PSI for the piping.
Stage I Vapor Recovery Testing
Required Annual Tests for Stage I Systems
Gasoline dispensing facilities (GDFs) must visually inspect their Stage I systems weekly and must perform the following tests of the Stage I system at least once every twelve months:
- A Pressure Decay 2-inch Test (CARB TP-201.3)
- A Vapor Tie Test (San Diego Air Pollution APCD TP-96-1, section 5.1.9)
- A Pressure/Vacuum Vent Valve Test (CARB TP-201.1E)
- A Static Torque Rotatable Adaptor Test (CARB TP-201.1B) for GDFs with EVR rotatable product adaptors and/or vapor adaptors, and
- For GDFs with a Stage I EVR system, either a Leak Rate of Drop Tube/Drain Valve Assembly Test (CARB TP-201.1C) or a Leak Rate of Drop Tube/Overfill Prevention Devices Test (CARB TP-201.1D)
Actions to take when Stage I Tests Fail
Any owner/operator of a motor vehicle fuel dispensing facility whose Stage I system fails one or more required in-use compliance tests (310 CMR 7.24(3)(e)1.), shall:
- Immediately repair or replace the incorrectly installed, non-functioning or broken component in accordance with the applicable Executive Orders and manufacturers’ guidance;
- If any Stage I system component is replaced, it shall be replaced with a CARB EVR component (except coaxial components and slip-on spill buckets may be non-EVR) and installed in accordance with applicable Executive Orders and manufacturers’ guidance;
- Retest and pass each failed test; and • Submit to the Department an Annual In-Use Compliance Certification with passing test results for all required tests on or before the facility’s Annual In-Use Compliance Certification submittal due date or within 30 days of the date of the first passing test result, whichever occurs first.
- If the Stage I system failed one or more required in-use compliance tests and the system could not be immediately repaired you must cease the transfer of motor vehicle fuel into the motor vehicle fuel storage tanks equipped with the failing Stage I system until the system is repaired in accordance with the applicable CARB Executive Orders and manufacturers’ guidance and all applicable compliance testing was conducted and passed.
Aboveground Tank Testing
Aboveground tank testing in Massachusetts involves the use of an ultrasonic test instrument that measures the thickness of the tank walls. We use this sophisticated technology because the human eye can’t determine how sound the steel is that’s holding back almost a whole ton of oil. This test, which is generally conducted on tanks larger than 1000 gallons, uses advanced algorithms to measure the thickness of the tank wall, coating, and corrosion, helping to predict the life of the tank. The ultrasonic process is non-invasive and can be conducted in about fifteen minutes. Ideally it should be performed as part of the your annual tank inspection and fuel system maintenance.
Leak Locating in Storage Tanks and Lines
If your tank or line test fails we can quickly locate the source. We take the guesswork out of finding the location of your tank or line leak. Aboveground tanks can be pressurized and tested with a leak detection bubble mix but underground tanks and lines aren’t accessible unless you excavate them. Before you make the decision to excavate, make sure you know where the source is. CommTank uses Helium or Hydrogen as a tracer gas for underground tanks because it rises to the surface where it can be detected with a small lateral spread. Helium is an inert gas and is safe to use in all tanks and piping but is subject to shortages and not always available. Hydrogen when blended with Nitrogen ensures high accuracy and has no toxic effects since the mix is classified as non-flammable. The leak detector used to measure these gases is accurate to within 2 feet in most instances and is an excellent compliment to acoustic techniques. The steps for line leak location are similar to tank leak locating but the lines are typically isolated and drained when a tank top can be accessed through a manway and sump.
For examples of our work please see the tank testing projects section of our web site.
Contact CommTank today for innovative tank testing in Massachusetts and New Hampshire: 1-800-628-8260