Today, CIRIA C736 is the cornerstone of effective water pollution prevention. It provides best practice guidance and clear examples of how to design and implement reliable containment systems. Prior to this, solutions were often developed based on experience, limited data, and engineering judgement.
If you are currently reviewing your site’s pollution containment strategy, we can help interpret CIRIA C736 and assess your system — contact us to discuss your requirements.
Abbey Metal Finishing appears as a case study within CIRIA C736 (Section 12.1). If you need a copy, it is freely available, or we can provide a compressed version for easy sharing. This project remains particularly important to us. Abbey Metal Finishing were instrumental in pushing the development of robust, engineered containment solutions — and the work carried out together is now recognised as best practice within CIRIA guidance.
The Incident
Abbey Metal Finishing is a COMAH-regulated site. In 2010, they suffered a major fire — similar in nature, though smaller in scale, to the Buncefield explosion.
The environmental impact was not caused by the fire itself, but by contaminated firewater runoff.
- Cyanide escaped from the site
- Approximately 27,000 fish were killed
- The company was prosecuted and fined ~£166,000 in 2013
- Clean-up, legal, and regulatory costs were substantial
The business was left in a critical position.
What Went Wrong
At the time, the site relied on a Penstock Valve for containment.
This system failed.
- The valve did not seal
- It had likely never been tested
- Firewater escaped through the drainage network directly into the river
Containment systems that are assumed to work — but are never proven to work.
If you are unsure whether your current containment system would perform in an emergency, we can review and validate your setup — speak to our team.
Regulatory Pressure & Business Impact
Following the incident:
- The factory was destroyed
- Over 200 employees were affected
- The regulator refused operating permits
- The business could not rebuild without proving effective containment
The message from regulators was clear: Containment systems must be demonstrably reliable — not assumed.
The Challenge
Abbey needed to:
- Relocate to a new site
- Prove full firewater containment capability
- Secure regulatory approval
At this stage, CIRIA C736 did not yet exist.
There was no formal roadmap — only engineering judgement and risk-based design.
Engineering the Solution
The first step was understanding the drainage system.
We carried out:
- Full drainage mapping (visual inspection, chamber lifting, level measurement)
- Topographical modelling
- Identification of all flow pathways
Key risks identified:
- Uncontrolled discharge routes
- Interconnection with foul drainage
- Inadequate containment boundaries
All foul connections were isolated using sealed covers to prevent contamination spread.
Containment Strategy
The solution focused on tertiary containment — protecting the environment beyond the immediate process areas.
We implemented:
- Engineered retaining structures
- Full drainage isolation strategy
- Two automated ToggleBlok® pollution containment valves
These valves:
- Close immediately on activation
- Can be triggered by fire alarm or power failure
- Allow remote activation from a control room
- Provide reliable, repeatable sealing
Systems like this can typically be integrated into existing infrastructure with minimal disruption — contact us to explore options for your site.
Implementation
The system was installed in just three days (with minor client-led adjustments).
This enabled:
- Reapplication for operating permits
- Regulatory approval
- Full return to operation within two years
Abbey Metal Finishing have since upgraded to newer versions of the system.
For detailed specifications or retrofit options, request technical information from our team.
Industry Impact
This project directly contributed to the development of CIRIA C736.
Graham Vaughan (Environmental Manager at the time) worked closely with the CIRIA team and supported knowledge sharing by hosting site visits.
This collaboration helped shape:
- Modern containment principles
- Practical implementation approaches
- Real-world validation of system design
Evolution of Best Practice
At the time of the project:
- There was no formal guidance
- Designs relied on assumptions and modelling
- Validation was limited
Today, CIRIA C736 provides a clear framework.
We now apply it to every project to ensure:
- Compliance
- System reliability
- Proven performance under emergency conditions
Modern Approach: Beyond Compliance
Since this project, we have further developed our capabilities, including:
- Spill Mapping — modelling worst-case scenarios
- Enhanced automation and connectivity
- Improved installation efficiency
Spill Mapping allows decision-makers to:
- Visualise risk
- Quantify containment requirements
- Invest based on evidence, not assumption
If you would like to understand the real pollution risk on your site, we can model and demonstrate worst-case scenarios — get in touch to learn more.
Regulatory Landscape Today
Since 2015, sentencing guidelines have changed significantly.
Fines are now based on group turnover, not just the operating entity.
For large organisations, this can increase penalties dramatically.
Effective containment is no longer just an environmental issue — it is a board-level financial risk.
Conclusion
Abbey Metal Finishing is a defining example of what happens when containment systems fail — and what can be achieved when they are engineered correctly.
Today, with CIRIA C736 and modern technology:
- There is clear guidance
- There are proven solutions
- There is no need to rely on assumption
Every site presents different risks and constraints.
We work with engineers, consultants, and operators to design compliant, reliable containment systems.
Contact us to discuss your project or request further information.
Need help implementing CIRIA C736?
Containment strategies should always be developed based on site-specific risk, drainage layout, and operational requirements.
Our team supports engineers and consultants in applying CIRIA guidance to real-world projects.
