Containment Systems For The Prevention Of Pollution

Why you should read this guideFollowing the good practice in this guide will help you minimise the pollution risks associated with youroperations. However, it will also help with the management of risks and opportunities at corporate levelthat might include:99 Penalties, liabilities and reputational issuesIneffective containment of pollutants can result not only in environmental harm but can also havea severe effect on the company concerned. In the past, fines imposed for pollution offences weretrivial compared with the cost of installing protective measures. However fines have been increasedsignificantly and in July 2010 five companies were fined a total of 9.5m for their part in the Buncefieldcatastrophe, a disaster that it is estimated had a total cost exceeding 1 billion.99 Corporate governanceCorporate governance demands that asset owners understand the value of their portfolio, includingfuture maintenance and risks to operation. This is clearly applicable to the containment systems coveredin this guidance.99 Corporate social responsibility (CSR)While companies regard legal compliance as a major priority, leading organisations are now striving toimprove their reputational image and are becoming more open in the publication of information relatingto their environmental performance.Lessons learned from past incidents and near misses have illustrated that many of the preventativemeasures are relatively straightforward to implement as illustrated on the following pages.viCIRIA, C736

Lessons learned from incidentsThis publication provides guidance on the measures that site operators can take to minimise the riskof pollution from leaking or burning substances stored on site. Many of these measures are relativelystraightforward in terms of how sites are designed, operated and maintained. The examples from twokey references shown in the following box illustrate some of the consequences that have arisen from notincorporating these measures.Major accident to the environment (MATTE): UK case studies of incidents and near misses 1999–2010 (HSL, 2012)123Serious environmental harm is most frequently associated with release of liquids to ground and water, as opposed toaerial dispersion of pollutants.There is a need to consider the quantities of firewater that are likely to be produced throughout the incident (notjust first response), the rate at which runoff will be generated and how this will be successfully managed and retained.Loss of liquid material to the environment via hitherto unknown pathways, or because of the availability of pathwaysdue to a lack of impermeable barriers, was common to a number of cases:a failings in oversight were underlying factors typically a failure to foresee and plan accordinglybfailure to adequately manage ageing plant continues to be highlighted as a significant underlying causal factor.Buncefield: Why did it happen? The underlying causes of the explosion and fire at the Buncefield oil storage depot,Hemel Hempstead, Hertfordshire on 11 December 2005 (HSE, 2011)12345678The bunding at Buncefield had many flaws, which caused large volumes of fuel, foam and firefighting water to leakout of the bunds. Bunds were not impermeable and not fire resistant. The bunding was unable to handle the largevolumes of firewater involved in the incident.Generally, the concrete performed well in resisting the burning fuels but the bunds failed badly at the joints and wallswhere pipes penetrated them.One of the bunds at Buncefield contained metal waterstops within joints. Even though this bund was exposed to abund pool fire and tank fires, the joints performed well and did not leak significantly.Other bunds had plastic waterstops with metal plates over the inside face of the joint. These joints also maintained theirintegrity as the plastic waterstop and other joint material was protected from thermal impact by the metal cover plate.Three bunds performed particularly badly. The joints (floor and wall joints) did not contain waterstops. During the firethe sealant and other joint materials (which were not fire resistant) were badly damaged. Many of the joints leakedallowing fuel, foam and firewater to flow onto the site roadways.One bund was constructed with tie bars penetrating through the bund and although they were plugged and grouted,they were unable to resist the impact of the fire. Holes opened up, which were further pathways for leakage of fuel,foam and firewater from the bund.Many of the bunds had pipes penetrating through walls and floors, and failures at these points meant the bunds couldno longer retain liquids. Broadly, there were three ways loss of integrity occurred:icatastrophic failure of the walls at pipe penetrations, likely due to thermal expansion of the pipeworkii some of the product pipes leading from the tanks ruptured and leaked so that there was an escape of fuel viadamaged pipes through the walls and out of pipes in unbunded areasiii loss of seal between pipes and walls.There was virtually no tertiary containment in place. Containment systems outside the bunding amounted only to thesite’s drainage systems, designed for rainwater and minor spills and losses of product, which would flow to interceptors and the site’s effluent treatment plant. The drainage was not designed for any large-scale releases from bunds,such as those that occurred. Specific flaws included: there was no kerbing or boundary wall/mound to keep liquids on site and direct them into drainage systems.Once released, liquids could flow anywhere the capacity of the drains and the lagoon was too small some of the drains were ‘perforated’ so that a ‘back-up’ of liquids would cause their release throughunderground perforations the liner of the firewater lagoon was susceptible to fire damage and to damage from debris from the explosion one lagoon was intended as a firewater supply, but was rendered useless as it received fuel draining from thesite. It flooded the fire system pump house when it overflowed there was a dependence on pumping liquids, which as a process is vulnerable to, for example:inadequate pumping capacityfailure of pumps on loss of powerinability to use pumps following release of flammable vapoursome areas of unmade ground were not protected from liquids and one such area of the site included a soakawaythe effluent treatment plant included soakaways that were not identified in the safety reports or emergency plans.Collectively these flaws allowed large volumes of fuel, foam and firewater to leave the site.More information on the Buncefield incident can be found at: www.buncefieldinvestigation.gov.ukContainment systems for the prevention of pollutionvii

Overview of this guidanceThe guidance is divided into 12 chapters and grouped into three parts, summarised here:PartChapter123Contents1Introduction2Risk assessment and classification* of secondary and tertiary containment systems3Containment options4Containment system capacity5Existing installations6Introduction to bunds7In situ reinforced concrete and masonry bunds8Earth banked containment basins (lagoons), earth bunds and earth floors9Containment tanks10Transfer systems11Sacrificial areas and temporary containment12Repair and upgrading of existing containment facilities* Note that the key recommendations contained in the guidance with respect to the ‘class’ of containment are indicated in the margin withthe key icon:The key plan and accompanying text provides a summary of the contents of each chapter and givesexamples of the scope of each chapter with reference to particular elements of an idealised facility. It isintended to be used as an aid to the reader in navigating the guidance.Key plan62123713114410911581615viiiCIRIA, C736

Key plan notesChapter 1: IntroductionThe introduction sets out the scope of the guidance, provides an overview ofthe fundamental principles upon which it is based and includes a high-levelsummary of related guidance and legislation.Chapter 2: Risk assessment and classificationAt the core of the guidance is a risk assessment and classification methodologythat determines the ‘class’ of containment required, ie class 1, 2 or 3. The classthen determines the design and specification requirements for the secondarycontainment system.Chapter 8: Earth banked containment basins (lagoons) and earthbundsWhere the site topography and the ground and soil conditions are suitable,earth embankments can provide a cost effective means of providing bothlocal secondary containment (earth bunds [4]) and remote secondarycontainment basins (lagoons [5]).This chapter provides advice on assessing the suitability of a site, aperformance specification and recommendations and guidance on theirdesign and construction appropriate to the class of containment.Chapter 9: Secondary containment tanksChapter 3: Containment optionsThis chapter defines primary, secondary and tertiary containment and anumber of system types – local, remote and combined.Examples: tanks, vessels and associated pipework [1] provide the primary containment.Secondary containment tanks [6] usually form part of a remote containmentsystem with, depending on the site topography, either a gravity or pumped[4] connection from a sump local to the primary containment, or from alocal secondary containment system. The chapter discusses the factorsthat should be considered in specifying a secondary containment tank andreviews a number of tank types.The primary containment may also be located within a warehouse [2] secondary containment can be provided by bunds constructed fromreinforced concrete [3] or earth [4], by lagoons [5] or by tanks [6]. Warehousewalls can also be designed to provide secondary containment [7] tertiary containment can be provided by a number of means includinglagoons [5], sacrificial areas such as car parks [8] and providing storageon the surface of roadways using containment kerbs [9] local containment is provided locally to the primary containmentnormally using a bund [4] [5] remote containment is provided away from the primary containmentusing, for example, a lagoon [5] or tank [6]. Transferring spilled inventoryto the remote containment can be via a gravity drain [10] (as shown bythe example of a loading bay [11]) or pumped combined containment uses both local containment and remotecontainment. The example shows a local containment (a bund [3]) withadditional remote containment (a tank [6]) connected via a pumpingmain [12].Chapter 10: Transfer systemsTransfer systems are the means for collecting and conveying spillage andcontaminated water from the primary containment to a remote secondaryand/or tertiary containment facility. The transfer system comprises thecatchment area local to the primary containment and the conveyancesystem (pipes networks, culverts, open channels, pumps and pumping mainsand even site roads) discharging to the remote secondary containment.The chapter provides the performance requirements that components of atransfer system should meet to satisfy the overall system classification.Examples: gravity system [10] draining a loading bay (catchment area) [4] to aremote secondary lagoon channel drainage [13] draining inventory overtopping (or due to failureof) failure secondary local containment [3] to a lagoon [5] providing (inthis example) tertiary containment tertiary containment provided by pumping [12] inventory fromChapter 4: System capacityThis chapter describes the process for determining the secondary andsite-wide capacity of containment systems based on a combination of theinventory, an allowance for accumulated rainfall and, where appropriate,firefighting and/or cooling water.Examples: secondary containment capacity requirement differs depending if asecondary containment [3] to a tank [6] road [14] with high containment kerbs [9] draining inventory overtopping(or due to failure of) secondary containment [3] [4] [7] to a lagoon [5] orsacrificial storage area [8] providing tertiary containment during an incident, runoff from drained areas [14] must be preventedfrom reaching the outfall to river [15] via the surface water drainagesystem [16] by closing a pollution control valve [17].single tank in a bund [3] or multiple tan ks in a bund [4] total site-wide capacity is a combination of all the containment capacityChapter 11: Sacrificial areas and temporary containmentChapter 5: Assessment of existing installationsThe sacrificial areas are designed to soak up the contaminants by containingthe spill within a depth of permeable soil or porous media. The method relieson interception of spills at the source and conveying the contaminated runoffto a remote area. Sites that may be designated for this purpose include carparks, landscaped areas, sports fields etc.including bunds [3] [4], lagoons [5], tanks [6] and other sacrificial andtemporary storage areas [8] [9].This guidance recommends that an operator is able to demonstrate that the‘class’ of the installation is appropriate to the use to which it is being put.This part of the document provides advice on the classification, inspection,maintenance and modification of existing installations.Chapter 6: Introduction to bundsThis chapter defines ‘bunds’ and for each class of containment providesa performance specification and recommendations and guidance on theirdesign and construction.Example: bunds include those constructed in concrete [3] and as earthTemporary containment areas provide preventative measures for dealingwith exceptional events that cannot be dealt with by the permanent facilityand may form part of a site’s emergency response procedures.This chapter provides advice on the design of sacrificial areas and temporarycontainment.Examples: spills drained by the roadway [16] to a sacrificial area provided by a carpark [16] roadway [16] with high containment kerb [16] provides temporarystorage. Spills prevent from reaching the river [16] via the surface waterdrainage system [16] by a pollution control valve [16].embankments [4].Chapter 12: Repair and upgrading of existing installationsChapter 7: In situ reinforced concrete and blockwork bundsIn situ built reinforced concrete and blockwork walls [3] are probably themost common form of bund construction. This chapter provides adviceon the design and specification of this form of construction appropriate toeach class of containment with emphasis is on the formation of joints anddetailing of pipe penetrations where these cannot be avoided.Containment systems for the prevention of pollutionThis chapter will provide advice on the repair and upgrading of existinginstallations with reference to other chapters in Part 3 as appropriate.Upgrading of an existing installation may be required following anassessment described by Chapter 5.ix

ContentsSummary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iiForeword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iiiAcknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ivWhy you should read this guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viLessons learned from incidents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viiOverview of this guidance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viiiGlossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiiiAbbreviations and acronyms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xixKey plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xx1Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.11.21.31.41.51.62Risk assessment and classification of secondary and tertiary containment systems . . . . . . . . . . . . . . . 112.12.22.32.42.52.63Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11Framework for classification of secondary and tertiary containment . . . . . . . . . . . . . . . . . . . . . . . 13Key elements for determining the site hazard rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152.3.1Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152.3.2 Pathway . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .182.3.3 Receptors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21Overall site hazard rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24Site risk rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26Containment classification system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 282.6.1Hazard and risk assessment and design classification . . . . . . . . . . . . . . . . . . . . . . . . . . . 28Secondary and tertiary containment options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 313.13.23.33.43.5xObjectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CIRIA C736 London, 2014 Containment systems for the prevention of pollution Secondary, tertiary and other measures for industrial and commercial premises I L W Walton SLR Consulting Griffin Court, 15 Long Lane, London, EC1A 9PN Tel: 020 7549 3300 Fax: 020 7549 3349 Email: enquiries@ciria.org Website: www.ciria.org