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Understanding the Latest Revisions to Florida's Fuel Tank Line Leak Detector (LLD) Rules

Underground Storage Tanks (USTs) play a crucial role in storing petroleum and other hazardous substances, but they come with inherent risks of leaks and contamination. To safeguard against environmental disasters and protect public health, the Environmental Protection Agency (EPA) mandates the use of release detection methods for UST systems. In this blog post, we will explore the significance of release detection and the various methods employed to ensure compliance.

Why is Release Detection Crucial?

The primary objective of release detection is to swiftly identify leaks from UST systems before they can spread and cause environmental damage. All regulated tanks and piping are required to have release detection in place to meet three fundamental requirements:

1. Detect a leak from any portion of the tank or its piping that routinely contains petroleum.

2. Install and calibrate the leak detection system according to the manufacturer's instructions.

Release Detection Methods for Tanks

Owners and operators of petroleum USTs installed on or before April 11, 2016, must employ at least one of the following leak detection methods or other agency-approved alternatives:

1. Interstitial Method:

- For USTs installed or replaced after April 11, 2016, secondary containment with interstitial monitoring is mandatory.

2. Internal Methods:

- Automatic tank gauging (ATG) systems

- Manual tank gauging

- Statistical inventory reconciliation (SIR)

- Continuous in-tank leak detection (CITLD)

- Tank tightness testing and inventory control (temporary method)

3. External Methods:

- Groundwater monitoring

- Vapor monitoring

Release Detection Methods for Piping

For pressurized piping installed on or before April 11, 2016, specific requirements include:

  • Piping must-have devices that automatically shut off or restrict flow or trigger an alarm if a leak is detected.

  • Conduct an annual tightness test or use one of the monthly methods: interstitial monitoring, groundwater monitoring, vapor monitoring, continuous in-tank leak detection, statistical inventory reconciliation, or other approved methods.

For suction piping installed before April 11, 2016, release detection requirements are based on specific characteristics. If the piping meets certain criteria, it may be exempt from release detection. Otherwise, it must undergo monitoring or testing.

Piping installed or replaced after April 11, 2016, must have secondary containment with interstitial monitoring, with some exceptions.

Regulatory Requirements for Suction Piping

Suction piping that matches certain design criteria is exempt from release detection. If it doesn't meet these criteria, it must undergo testing or monitoring, including line tightness tests, interstitial monitoring, vapor monitoring, groundwater monitoring, or statistical inventory reconciliation.

Regulatory Requirements for Pressurized Piping

Each pressurized piping run must employ a combination of an Automatic Line Leak Detector (LLD) and one other method, such as interstitial monitoring, vapor monitoring, groundwater monitoring, statistical inventory reconciliation, or an annual tightness test.

The LLD is designed to detect even small leaks and trigger alarms. Line tightness tests may also be used but have specific requirements.

How Do Release Detection Methods Work?

  • Automatic Line Leak Detectors (LLDs): These devices monitor pressure and flow rates, responding to pressure decreases or increases within the line. They can restrict flow, shut it off, or trigger alarms when a leak is suspected.

  • Line Tightness Testing: This method pressurizes the line and detects drops in pressure over time, indicating a possible leak.

  • Secondary Containment with Interstitial Monitoring: A barrier is placed between the piping and the environment, with monitors to sense leaks.

  • Vapor and Groundwater Monitoring: These methods detect products in the soil or groundwater near the piping, requiring careful site assessment for proper well placement.

Ensuring Compliance

Having the required release detection equipment or method is only part of the compliance equation. Proper operation and maintenance are crucial. Regular testing and monitoring, at least once a month, are essential to determine if the UST system has released any of its contents. Failure to do so can result in noncompliance, fines, and costly cleanups.

Release detection in UST systems is a vital component of environmental protection. Understanding the regulatory requirements and implementing the appropriate methods is essential to prevent contamination and ensure the safety of these underground storage facilities.

Stay on top of all Florida UST systems compliance requirements by contacting the petroleum equipment experts at Don Wood Inc. Call 407-293-0891 or visit

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