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Retrofitting Existing Tanks with Modern Overfill Protection Systems
Tank overfilling is a critical safety and environmental issue that can lead to catastrophic consequences, including soil and water contamination, tank ruptures, and even explosions. For facilities with existing tanks, retrofitting with modern overfill protection systems is essential to mitigate these risks. This article will delve into the various types of overfill protection systems, their advantages, and the considerations for retrofitting existing tanks.
Why Retrofit?
The risks associated with tank overfilling are significant. Liquid hydrocarbons pose a substantial threat to the environment and human safety. The ALARP (As Low As Reasonably Practicable) principle, often used in safety-critical systems, emphasises the need to reduce residual risk to the lowest possible level. Retrofitting existing tanks with modern overfill protection systems is a crucial step in achieving this goal
Types of Overfill Protection Systems
Mechanical Overfill Prevention Systems
Mechanical systems are a cost-effective and reliable option for preventing overfills. Here are a few types:
- Float Valve Systems: These systems use a float attached to a valve that blocks the fluid path as the tank level rises. While they are cost-efficient and suitable for small to medium capacity tanks, they can suffer from incremental closure, leading to throttled flow rates and potential pressure buildup
- Self-Climate LDR Models: These mechanical devices are mounted on the filler pipe and can be used for various fuels, including heating oil, diesel, and gasoline. They offer complete and automatic closure at predefined levels and are designed to prevent turbulence and foam formation
- Clean fill Models: Suitable for existing tanks where internal installation is not possible, these models are mounted outside the tank and can handle fill rates up to 40 m³/hour
Electronic Overfill Prevention Systems
Electronic systems offer advanced features and higher reliability:
- Stand-alone Electronic Systems: These systems use a high-level float switch or sensor that communicates with a logic solver to actuate a flow stop element. They are independent, can be deployed on vehicles or equipment, and allow for high refuelling speeds. However, they require power and can be more expensive
- Integrated Electronic Systems: These systems combine overfill protection with other tank gauging or fuel management capabilities. They use level sensors like ultrasonic or guided wave radar to identify the tank’s safe fill level and interact with a controller unit to stop the supply pump or close a valve. These systems are more expensive but offer comprehensive fuel management solutions
Safety Instrumented Systems (SIS)
For high-risk applications, SIS provides the last line of defence:
- SIS Systems: Designed to achieve specific Safety Integrity Levels (SIL), these systems include high level sensors, logic solvers, and actuated valves. They ensure that the system fails to a safe state and provide absolute assurance against tank overfills. However, they are complex and costly.
Considerations for Retrofitting
Compatibility and Installation
When retrofitting existing tanks, it is crucial to ensure the new overfill protection system is compatible with the tank's specifications and fill rate requirements. For example, mechanical systems like the Self Climate LDR models need to be mounted on the filler pipe, while electronic systems require proper installation of probes and sensors
Maintenance and Inspection
Regular maintenance and inspection are vital for the effectiveness of overfill protection systems. Ensure that the chosen system aligns with your maintenance capabilities and that routine inspection and testing guidelines are followed. Hidden or hard-to-reach components, such as those in float valve systems, require special attention
Power and Connectivity
Electronic systems require power, which can be a limitation in the event of a power failure. Ensure that any electronic system chosen has a fail-safe design and consider backup power options if necessary. Integrated electronic systems also require a communications link for interfacing with fuel management software
Risk Assessment
The choice of overfill protection system should be based on an application-specific risk assessment. Consider the type of fluid, tank size, fill rate, and the level of supervision during the filling process. For instance, float valve systems may be sufficient for small, supervised fills, while SIS systems are necessary for high-risk, unsupervised operations
Retrofitting existing tanks with modern overfill protection systems is a critical step in ensuring safety and environmental protection. By understanding the different types of overfill protection systems, their advantages, and the considerations for installation and maintenance facilities, can make informed decisions to mitigate the risks associated with tank overfilling. Always conduct a thorough risk assessment and follow best practices to ensure the chosen system meets the specific needs of your operation.
Operational Reliability and Redundancy
Reliable Tank Filling: Systems like Banlaw’s FillSafe Power and FillSafe Zero ensure reliable tank filling every time, with features such as LEDs for immediate operator feedback and secondary backup overfill prevention.
Retrofitting existing tanks with modern overfill protection systems is crucial for enhancing safety, efficiency, compliance, and financial stability, while also ensuring the long-term reliability and environmental integrity of the facility.
Contact Banlaw today for a tank overfill protection system which will improve the productivity of your fleet. Fast Fills. No Spills.
