A Practical Guide to:

CIRIA C736: Containment Systems for the Prevention of Pollution

Overview

CIRIA C736, “Containment systems for the prevention of pollution” (2014), is a best practice guide designed to help businesses prevent environmental harm through properly designed, maintained, and inspected containment systems.

Developed in response to high-profile pollution incidents - most notably the Buncefield Oil Terminal fire in 2005 - this guidance outlines how organisations can protect both the environment and themselves from regulatory penalties, reputational damage, and operational disruption.

Whether your site has a single tank or multiple chemical storage areas, if your operations pose a risk of spill or environmental contamination, CIRIA C736 applies to you.

The Legislative Context

While CIRIA C736 is guidance - not law - it is rooted in and strongly supported by key UK environmental legislation, including:

  •  Environmental Permitting (England and Wales) Regulations 2016
  •  Pollution Prevention and Control (Scotland) Regulations 2012
  •  Control of Pollution (Oil Storage) Regulations across all UK nations
  •  Pollution Prevention and Control Act 1999
  •  Control of Major Accident Hazards (COMAH) Regulations 2015

In the event of a pollution incident, regulators won’t just check if the legal minimum has been followed - they’ll examine whether recognised best practices, like those set out in CIRIA C736, have been implemented to mitigate risk.

Who Should Follow CIRIA C736?

CIRIA C736 is essential reading for:

  •  Industrial sites with chemical or oil storage
  •  COMAH sites (under Control of Major Accident Hazards))
  •  Commercial premises storing hazardous substances
  •   Facilities in flood-prone areas or with fire risk
  •   Any business with a secondary or tertiary containment system in place

It applies to a broad spectrum of containment strategies - from bunds around oil tanks to drainage shut-off valves - and provides guidance for both new installations and upgrading systems.

Key Principles of CIRIA C736

The guide outlines how to plan, build, and maintain robust containment systems to withstand incidents such as:

  •  Fires and explosions
  •  Floods and heavy rainfall
  •  Equipment failures or overflows
  •  Operator error

It covers:

  •  How to conduct risk assessments for containment failure
  •  Guidance on the design and specification of secondary and tertiary systems
  •  Upgrades to existing infrastructure
  •  Inspection and maintenance routines
  •  Automated systems to reduce human error

Practical Example: After Buncefield, poorly designed containment allowed pollutants to escape. CIRIA C736 aims to prevent a repeat by ensuring bunds are sealed, drains are protected, and firewater is properly managed.

Why Compliance Matters

All regulated oil containers must have secondary containment to prevent environmental harm in case of leakage. Acceptable methods include:

  •  Regulatory Defence: In the event of an incident, being able to demonstrate alignment with CIRIA C736 can be a powerful mitigating factor during regulatory investigation.
  •  Fines and Legal Action: Companies that fail to maintain or inspect their containment systems - particularly if they ignored guidance like CIRIA C736 -face significantly higher penalties under UK environmental law.
  •  Operational Downtime: Environmental incidents often require clean-up, third-party audits, and enforcement-imposed downtime. These interruptions can disrupt operations for weeks - or longer.
  •  Reputational Damage: Pollution events often draw scrutiny from regulators, insurers, and the public. Being known for poor environmental stewardship damages business trust and can harm stakeholder relationships.

Steps to Compliance with CIRIA C736

  1. Specify containment systems appropriately: Ensure all secondary and tertiary systems are correctly designed for the materials, volumes, and risks on site.
  2. Implement a formal inspection regime: Schedule routine checks (e.g. monthly/quarterly) and detailed periodic inspections (e.g. annually or every 5 years).
  3. Address deficiencies promptly: Any damage, defects, or design issues must be remedied without delay - or an improvement plan must be in place.
  4. Maintain documentation: Keep detailed, accessible records of all inspections, maintenance work, testing, and risk assessments.
  5. Automate where appropriate: Automated drain closure systems, for example, reduce human error and response lag during emergencies.

Read the full CIRIA C736 document here.

How GPT Environmental Can Support Your Compliance

At GPT Environmental, we help businesses reduce pollution risk and ensure regulatory compliance through:

  •  Containment system assessments and upgrades
  •  Regular inspection, testing, and documentation services
  •  Automated spill and firewater shut-off systems
  •  Emergency support and remedial works
  •  Ongoing compliance audits aligned to CIRIA C736 and ISO 14001

Whether you’re preparing for an ISO audit, responding to a near-miss, or proactively planning your containment strategy we can help simplify the path to compliance.