Full Retention Separator
Full Retention Separators (BS EN 858-1 Compliant)
Heavy-duty surface water separators engineered for high-risk industrial facilities, fuel distribution depots, and vehicle recycling yards. Treats 100% of surface runoff up to maximum design rainfall intensity with zero bypass.
Total Flow Containment for High-Risk Sites
Cowens **Full Retention Separators** are engineered specifically for sites where significant hydrocarbon contamination or catastrophic fuel spillage risks exist. Unlike bypass systems, full retention separators treat the entire volume of surface water runoff generated by a rainfall event up to 50 mm/hr.
Each unit is equipped with a primary silt trap, a high-efficiency coalescing plate stage (reducing discharge to less than 5 mg/L of oil), and an **Automatic Closure Device (ACD)**. In the event of a major oil spill or when oil capacity is reached, the ACD automatically seals the outlet, trapping contaminants within the unit to protect surrounding waterways.
High-Risk Applications
- Fuel Storage Depots & Refuelling Bays: High risk of bulk fuel spillage.
- Scrap Metal Yards & Vehicle Dismantlers: High concentration of oils, hydraulic fluids, and battery residue.
- Bus Terminals & Haulage Yards: Heavy diesel vehicle parking and maneuvering areas.
- Chemical Storage & Industrial Loading Docks: Unloading zones requiring absolute environmental containment.
Technical Specifications
| Parameter | Specification / Feature |
|---|---|
| Standards Compliance | Full compliance with British & European standard BS EN 858-1 / 858-2 |
| Separator Performance | Class 1 output discharge quality (< 5 mg/L hydrocarbon content under test conditions) |
| Flow Processing Capability | Treats 100% of surface flow up to 50 mm/hr design rainfall intensity |
| Safety Shut-Off System | Integrated float-activated Automatic Closure Device (ACD) to prevent oil discharge |
| Tank Construction | Structural GRP shell or resin-coated reinforced steel for heavy ground loadings |
| Mandatory Alarm Monitoring | Compatible with Cowens CB2022 / CB2800 high oil and silt level alarm systems |
Frequently Asked Questions
A **full retention separator** is mandatory when site activities carry a high risk of major spills or ongoing heavy oil leaks—such as fuel storage facilities, scrap yards, haulage depots, and refuelling areas. Bypass separators are only permitted in lower-risk locations like car parks.
The ACD uses a calibrated float that sinks in oil but floats in water. When the layer of accumulated oil in the separator reaches maximum capacity, the float drops to seal the discharge outlet, holding all oil safely inside the tank until it can be emptied by a licensed waste contractor.
Sizing depends on the total catchment surface area ($m^2$) draining into the separator. Our technical engineering team calculates the required Nominal Size (NS) based on BS EN 858-2 design formulas.
Request Full Retention Separator Sizing & Quote
Our technical team in Carlisle provides full support for calculating drainage surface areas, selecting nominal sizes (NS), and ensuring compliance with UK Environment Agency guidelines.
📞 Direct Line: 01228 710205
✉ Email Support: [email protected]
📍 Factory Location: Carlisle, Cumbria, UK
