Imagine a low-pressure bulk liquid cargo tanker pulls into the loading bay of a heating oil plant. The driver exits the vehicle to log the trip and plan for their multi-state route transporting nearly a full tank of heating oil. Due to distraction or lack of visibility, the technician loading the heating oil into the cargo tanker just misses the target fill level. Unfortunately, the liquid being pumped goes past the target fill level to the full capacity of the large cargo tanker in a matter of seconds. The result is a 30 gallon spill of heating oil out of the tanker and around the loading area. The spill is recorded, evaluated, and regulated by the US Department of Transportation’s Pipeline and Hazardous Materials Safety Admission in conjunction with the Environmental Protection Agency (EPA).
In 2011 this incident actually occurred, creating a significant clean-up and compliance burden for the operators. A process that had worked many times without issue lacked the proper controls to mitigate significant risk. This miscalculation or oversight created a significant liability for all involved. As underscored by the DSDOT PHMSA (US Department of Transportation’s Pipeline and Hazardous Materials Safety Admission) and EPA (Environmental Protection Agency) guidance, these spills occur more often than they should during routine chemical loading events. Read about EPA Spill Prevention and Department of Transportation Pipeline and Hazardous Materials Safety Administration guidance.
Stemming from these kinds of accidental occurrences best practices, and additional industrial fluid controls became more common-place for batch loading of tank cars, tank trucks, marine barges, as well as free standing tanks and chemical storage units of both open and closed domes.
Drivers have regular safety checks they complete in conjunction with their loading technician, including wearing the appropriate PPE, making sure their vehicle is prepped to receive the load, and establishing clear communication with the loader. During the loading process the risk for a catastrophic event increases as just a short amount of time can cause a major environmental issue. It is imperative to have a detailed loading protocol in place that accounts for all infrastructure and safety considerations.
Since loading for liquid terminal operations can be one of the riskiest parts of the full process, Dixon Industrial Fluid Control has created a suite of products to mitigate some of that risk by acting as an additional control against unforeseen issues.
Due to different functionalities, equipment, or chemical type the batch loading process can require disparate amounts of time and attention across various industrial processes. This vacuum of time can create room for error where a technician might engage in another issue during the fill or not fully realize that a fill has been completed before it is too late. Dixon’s ADS Outalarm was designed specifically to help answer those uncertainties. With capacitance probe lengths of multiple sizes, including, 2ft, 3ft, 4ft, and 5ft, the ADS Outalarm can be placed at the top of tanker truck, tank car, or marine barge fill opening, as well as at the top of an open or closed dome chemical storage structure before filling commences. By choosing desired fill level or outage and adjusting the height of the capacitance probe the batch fill loading process enjoys overfill protection by sounding a verbal alarm and visibly flashing LED lights once the desired fill level has been reached. This allows the team completing the batch fill to ensure the flow is cut off before desired levels are exceeded. It also eliminates the need for a technician to have to visually mark the fill target by positioning themselves on top of the chemical storage unit being loaded. This is especially important when loading volatile chemicals that present inhalation hazards. This product can service most batch loading and overfill protection needs by offering a standard, hi-temperature, and conductivity option for the ADS Outalarm. Please consult with one of our experts to understand which option and what probe length would be right for your specific application.
Hypothetical Use Case of Loading Protocol: A low-pressure bulk liquid cargo tanker pulls into the loading bay of their heating oil plant. The driver turns the vehicle and other electronics off before exiting to complete their standard safety inspection. If applicable, they ensure they are using the appropriate protective equipment before exiting the vehicle. This inspection includes the vehicle being loaded, surrounding area, and equipment being used. Trailer compartments are checked and clear communication with the loading technician is established. If applicable, the grounding interlock is connected and static from the loading fitting is discharged. The portable, self-contained ADS Outalarm is inserted into the top of the tanker fill opening with the correctly adjusted probe height. Before being inserted the probe height is double checked to ensure length selected matches the desired fill level and accounts for the needed amount of vacant space based on application. Proper tuning, testing, and adjustments are completed before initial use. After the chemical fill is commenced and the alarm is triggered the batch loading job ends and time is allowed for complete draining. The ADS Outalarm is removed and wiped clean of any residue along with the chemical transfer device. The fill opening is closed and the ADS Outalarm is stored safely nearby. If applicable, the same process is completed for other compartments. Finally, the grounding interlock is disconnected. The driver or technician complete a final walk around inspection to ensure the batch load has been completed correctly and all tools are properly stored for the next use.
ADS Outalarm Difference: Without the overfill protection of the Outalarm, the batch loading technician would have had to position themselves to visually call for the moment of target fill level between the transfer hose and the bulk liquid cargo tanker. They would simultaneously have to shut off the load valve. While the technician should avoid distraction and be fully focused on the batch loading, the combination of human error and disparate load times can create unforeseen instances of distraction. Depending on the equipment being used and the chemical being transferred some batch fills of chemical storage facilities can be completed in a few minutes while others could take over an hour. With the Outalarm the likelihood of these mistakes is reduced to a minimum. Even if a technician were momentarily distracted, they would have to be out of earshot of the alarm to miss the stop queue.
The above hypothetical use case is meant to illustrated a potential scenario where the ADS Outalarm is used effectively after testing, tuning, and being incorporated into an already safety consciously loading process. Should not be used as a instruction of the chemical batch loading process. The ADS Outalarm is not a full substitution for safe batch loading protocol. Appropriate overfill protection requires a loading process cognizant or hazards and risks at every stage. The Outalarm provides helpful risk mitigation for one of those steps. Every batch load industrial process is different and a specialist should be consulted on protocol for completing a batch load.
ADS Outalarm® with Capacitance Probe
Applications: Specifically designed for liquid terminal operation on batch loading and overfill protection, tank cars, tanks trucks, marine barges; suitable for open and closed domes.
Box Quantity: 1ea
Temperature Range: -14°F to 250°F | -26°C to 121°C (Higher Temp Outalarms Available)
Lengths: 1ft, 2ft, 3ft, 4ft, 5ft, 6ft, and 7ft
Category: Dixon Industrial Fluid Controls
Brand: ADS and Dixon
- Totally self-contained; no wires, tubing, or external power
- Rugged weather- and corrosion-resistant construction
- No moving parts, tip sensitive phase shift™ digital capacitance sensor for conductive and nonconductive fluid, conductivity sensor with integral splash shield
- Requires no calibration or adjustment
- Adjustable insertion length through a standard ½" NPT fitting
- High-intensity audible and flashing visual outputs
- Optional opto-isolated solid state contact output
- Full, hard graduated laser engraved rod
- A100 operates up to 2,500 hours on a single 9V alkaline battery in standby mode
- Fail-safe, continuous battery monitor goes to alarm state on low battery
- Battery current drain <0.23 mA during standby; <50 mA in alarm state
- Intrinsically safe design per ANSI/UL913 Class I, Div I Groups A, B, C and D Hazardous Areas
- Minimum dielectric constant 1.7
- Activation point 1/4" above liquid surface
- Compatible with any liquid or dry bulk material with a dielectric constant of 1.7 or greater
- Conductive probes available for other media(most common Alcohol and HCL)
- Horn intensity 101 dB at 2'
- Light output 3 each 3000 mcd high intensity flashing LED's
- Pressure rating on standard unit: 50 PSI, applications up to 300 PSI available upon consultation
Dixon® Industrial Fluid Control manufactures products specifically designed for liquid terminal operations. There are numerous additional applications, materials, and custom designs available for overflow protection.