Annual Release Detection Functionality Testing
Written by: Brian Pottebaum, Director of Training Services
Release detection is a task that UST operators must perform monthly to confirm and document any fuel that may have been lost from the fuel storage tank and delivery system.
Release detection has been around for over 30 years, but recently more regulatory requirements have been added to verify that equipment is functioning properly and maintaining compliance with state and federal regulations. These requirements are often referred to as annual release detection functionality testing. As you would expect, the specific requirements and equipment depend on the method of release detection you are performing.
Methods of Release Detection
Although there are multiple release detection method options for existing UST facilities, newer systems are limited to only one method, Interstitial Monitoring (IM). Newer systems must also meet specific installation guidelines to accommodate this method of release detection.
All new and replaced UST systems must be secondarily contained (i.e. double walled) and use IM as the primary release detection method. UST systems installed prior to the state specific deadline have the option to use any approved release detection method, which includes IM if the secondary containment system is properly installed and functional. Acceptable methods of monthly release detection include the following:
- Interstitial Monitoring (IM) can be used for tank and piping release detection monitoring. IM uses a barrier, an outer wall, or a liner around the UST or piping to provide secondary containment. Secondary containment provides a barrier between the tank or piping and the environment. The barrier is designed to contain the leak until it is detected by a sensor, gauge, or visual inspection.
- Automatic Tank Gauging (ATG) can be used for tank release detection monitoring. ATG uses a probe installed in the tank that is connected to a monitor to provide information on product level and temperature. These systems calculate changes in product volume that can indicate a leaking tank.
- Continuous In-Tank Leak Detection (CITLDS) can be used for tank release detection monitoring and some methods provide piping release detection as well. CITLDS has two categories that methods fit into: 1) continuous statistical release detection, or continuous automatic tank gauging, (only monitors tanks) and 2) continual reconciliation (monitors tanks and piping). Both groups typically use probes/sensors permanently installed in the tank to obtain inventory measurements. They are combined with a microprocessor in the ATG system or other control console that processes the data. Continual reconciliation methods are further distinguished by their connection to dispensing meters that allow for automatic recording and use of dispensing data in analyzing tanks’ leak status.
- Statistical Inventory Reconciliation (SIR) can be used for tank and piping release detection monitoring. SIR analyzes inventory, delivery, and dispensing data collected by a tank monitor or manually with a tank stick to determine whether a UST system is leaking. The inventory data is provided to a certified vendor or entered into certified SIR software to be statistically analyzed for leaks.
- Manual Tank Gauging (MTG) can be used for tank release detection monitoring on smaller tank systems only. MTG may be used as the sole method of release detection for tanks with a capacity of 550 gallons or less and capacities between 551 and 1,000 gallons with a 48 inch or 64-inch diameter. MTG requires weekly tank stick readings and a monthly average to determine test results. Tank testing includes a comparison of stick readings that are separated by a predetermined “quiet” time; no fuel added or removed. The calculated leak rate must be within tolerance of the monthly EPA standard.
- Groundwater Monitoring (GM) can be used for tank and piping release detection monitoring if enough wells are properly located. GM uses permanent monitoring wells professionally installed close to the UST (usually 4 wells), with the wells extending below the groundwater level. Records of the site assessment and well installation must be maintained if the method is used on the UST system. A water sample is pulled from each well at least every 30 days and checked for the presence of leaked product. Monitoring can be done manually with a well bailer, or electronically with calibrated detection equipment.
- Vapor monitoring (VM) can be used for tank and piping release detection monitoring if enough wells are properly located. VM uses permanent monitoring wells professionally installed close to the UST or piping. Records of the site assessment and well installation must be maintained as long as the method is used on the UST system. A vapor sample is pulled from each well at least every 30 days and analyzed for the presence of product that could have leaked from the UST system. Monitoring must be done with approved electronic equipment.
- Automatic Line Leak Detection (ALLD) and Line Tightness Testing (LTT) is required on all pressurized piping and must be capable of continuously detecting a leak of 3 gallons per hour (gph) at 10 psi within 1 hour over the entire length of pipe between the UST and the furthest dispenser (including the piping between the dispensers). If a suspected release is detected, the ALLD device must react by shutting off product flow, restricting flow, or triggering an audible or visual alarm so the system can be shut down. In addition to the ALLD device, the pressurized piping system must have the ability to conduct an approved method of line tightness testing at 0.1 gph once a year, or continuous release monitoring every 30 days. Continuous monitoring would include IM, CITLDS (reconciliation), SIR, GM and VM.
Annual Release Detection Functionality Testing
The UST operator is responsible for confirming and documenting that all release detection equipment is functioning properly. This testing is required every year and “passing” records must be maintained at least three years. Please be aware that some states may have additional requirements and deadlines, check with your local regulatory agency for clarification. Here is a summary of the testing requirements for each method of release detection.
- Interstitial Monitoring (IM)
For non-electronic equipment (including manual gauges and dipsticks):
- Check for operability and serviceability
- Keep walkthrough inspection records for one year
For other equipment:
- Verify the system configuration (programming) of the controller/monitor
- Only as it relates to the liquid sensors; Does not include inventory/ATG probe
- Test alarm operability and battery backup related to IM system
- Inspect (liquid) sensors for residual build-up
- Ensure sensor communication with controller/monitor
- Automatic Tank Gauging (ATG)
- Verify the system configuration (programming) of the controller/monitor
- Test alarm operability and battery backup
- Inspect ATG probes and sensors for residual build-up
- Ensure floats move freely,
- the shaft is not damaged, and
- cables are free of kinks/breaks
- Continuous In-Tank Leak Detection (CITLDS)
- Verify the system configuration (programming) of the controller/monitor
- Test alarm operability and battery backup
- Inspect ATG probes and sensors for residual build-up
- Ensure floats move freely,
- the shaft is not damaged, and
- cables are free of kinks/breaks
- Statistical Inventory Reconciliation (SIR)
For handheld non-electronic equipment, such as tank gauge sticks:
- Check for operability and serviceability
- Entire stick must be readable to the nearest 1/8”
- Keep walkthrough inspection records for one year
For other equipment, if using ATG or electronic monitor/gauge:
- Verify the system configuration of the controller/monitor
- Test alarm operability and battery backup
- Inspect ATG probes and sensors for residual build-up
- Ensure floats move freely,
- the shaft is not damaged, and
- cables are free of kinks/breaks
- Manual Tank Gauging (MTG)
For handheld non-electronic equipment, such as tank gauge sticks:
- Check for operability and serviceability
- Entire stick must be readable to the nearest 1/8”
- Keep walkthrough inspection records for one year
- Groundwater Monitoring (GM)
For hand held non-electronic equipment, such as groundwater bailers:
- Check for operability and serviceability
- Keep walkthrough inspection records for one year
For other equipment:
- Verify the system configuration of the controller/monitor
- Test alarm operability and battery backup
- Inspect well probes and sensors for residual build-up
- Vapor monitoring (VM)
For hand held non-electronic equipment, such as groundwater bailers:
- Check for operability and serviceability
- Keep walkthrough inspection records for one year
For other equipment:
- Verify the system configuration of the controller/monitor
- Test alarm operability and battery backup
- Inspect sensors for residual build-up
- Test manual electronic devices, such as photoionization detectors
- Automatic Line Leak Detection (ALLD) and Line Tightness Testing (LTT)
- Sump sensors used for piping interstitial monitoring (IM) must remain as close as practicable to the bottom of interstitial spaces being monitored.
- Monthly monitoring records must be maintained for at least one year.
- Electronic and mechanical components of the system, including shutoff devices, sensors, pressure or vacuum monitors, must be tested annually for proper operation. Records of the test must be maintained for three years.
- Containment sumps that are part of the piping interstitial monitoring (IM) system must be tested at least once every three years for liquid tightness. Keep the results for at least three years.
For more information on these methods of release detection and the current regulations, please review Release Detection for Underground Storage Tanks and Piping: Straight Talk on Tanks.