Ground water monitoring
Secondary containment with interstitial monitoring
Automatic tank gauging systems
Tank tightness testing and inventory control
Manual tank gauging
Leak detection for underground suction piping
Leak detection for pressurized underground piping
Statistical inventory reconciliation
Automatic Tank Gauging Systems
Will I be in compliance?
When installed and operated according to manufacturer's specifications, automatic tank gauging systems (ATGS) meet the Federal leak detection requirements for new and existing USTs. A test performed each month fulfills the requirements for the life of the tank. (For additional leak detection requirements for piping, see the later sections on leak detection for piping.) You should find out if State or local requirements allow ATGs or have other requirements that are different from those presented below.
How does it work?
The product level and temperature in a tank are measured continuously and automatically analyzed and recorded by a computer. In "inventory mode," the ATGS replaces the use of the gauge stick to measure product level and perform inventory control. This mode records the activities of an in-service tank, including deliveries. In "test mode," the tank is taken out of service and the product level and temperature are measured for at least one hour.
What are the regulatory requirements?
The ATGS must be able to detect a leak at least as small as 0.2 gallons per hour. By December 1990, the ATGS must also be able to meet the Federal regulatory requirements regarding probabilities of detection and false alarm.
Will it work at my site?
ATGS have been used primarily on tanks containing gasoline or diesel, with a capacity of less than 15,000 gallons. If considering using an ATGS for larger tanks or products other than gasoline or diesel, discuss its applicability with the manufacturer's representative.
Water around a tank may hide a leak by temporarily preventing the product from leaving the tank. To detect a leak in this situation, the ATGS should be capable of detecting water in the bottom of a tank.
What other information do I need?
- The ATGS probe is permanently installed through a pipe (not the fill pipe) on the top of the tank. Each tank at a site must be equipped with a separate probe.
- The ATGS probe is connected to a monitor that displays ongoing product level information and the results of the monthly test. Printers can be connected to the monitor to record this information.
- For most ATGS, up to 8 tanks can be connected to a single monitor.
- ATGS usually are equipped with alarms for high and low product level, high water level, and theft.
- ATGS can be linked with computers at other locations, from which the system can be programmed or read.
- No product should be delivered to the tank or withdrawn from it for at least 6 hours before the monthly test or during the test (which generally takes 1 to 6 hours).
- An ATGS can be programmed to perform a test more often than once per month, if so desired.
Purchasing an ATGS is similar to any other major purchase. You should "shop around," ask questions, get recommendations, and select a method and company that can meet the needs of your site.
How much does it cost?
Total equipment cost ranges from about $5,000 for a basic system to $10,000 for a top-of-the-line system. The installation cost averages about $2,000-3,000.
- Monitor: $1,700-2,700; varies with manufacturer and whether a printer is included.
- Probes: $500-1,100/probe; varies with manufacturer.
- Cables: $0.15-1.00/foot; varies with the contractor and the part of the country.
Installation costs for a typical 3-tank system
- For a site that already has conduits for cables: $500 - 1,500.
- For a site in which conduit must be laid an average distance: $2,500 - 3,000.
- For a very complex site with many conduits running long distances and where rewiring is necessary: up to $10,000.