Guidance Manual On Underground Fuel Storage Tank Installations

Guidance Manual on Underground Fuel StorageTank InstallationsResearch & Contractor:Fluor Daniel GTI International LtdEnvironment AgencyRio HouseWaterside DriveAztec WestBristolBS12 4UDR&D Technical ReportP5.

Publishing OrganisationEnvironmentAgencyRio l-louseWaterside DriveAztec WestBristolBSI2 IUDFax: 0 1454 624409Tel: 0 I454 624400QEnvironmentAgency1996ofAll rights reserved. No partthisdocument may bc produced. stored in a rctricval syslcm. or transmlucd. in anyform or by any means. electronic. mechanical. photocopying. rccording or othcrw% wIthout the pcrmlssion ol‘thcEnvironmentAgency.The views expressed in this document are not necessarily those of the Environmentagents accept no liabilityAgency.Its ot’ficcrs. scrvanls orwhatsoever for any loss or damage arising from the intcrprctation or USCot’thc intiIrmation.or rcliancc upon views contained herein.Dissemination StatusInternal:Released to Regions.External:Restricted.Statement of UseThis document providesprotectionguidance on the installationof undergroundzones. Its primary purpose is to provide an introductionprocedures and considerationsin the control engineeringfuel storage tanks in groundwatcrto the engineeringmeasures available with respect to groundwaterResearch ContractorThis document was produced under R&D Project No 670 by:Fluor Daniel GTI InternationalLimitedIO First QuarterBlenheimoptions.for the benefit of Agency staff, who do not have a specialist backgroundRoadEpsomSurreyKT19 9QNTel: 0 1372 745995Fax: 0 I372 742027Environment Agency’s Project ManagerThe Environment Agency’s Project Manager for R&D Project 670 was:Jonathan Smith.R&D Technical Report P5.protection zones.

ivEXECUTIVESUMMARY. .1.1. INTRODUCTION.I1.1 Background .I1.1.1 The problem. .11.1.2 Aims and objectives. .2.1.2 m.2Protection (80/68/EEC). .1.2.1 EC Directive on Groundwater.21.2.2 Water Resources Act 1991 .3(SWQOs).1.2.3 Statutory Water Quality Objectives.3.ProtectionAct1990.1.2.4 Environmental.3Act1991.1.2.5 Water 6.41995.Act1.2.7 Environment4.1.2.8 Petroleum licensing officer’s duty5.1.3 General6.1.4 Definition of GramProtection.6Protection).1.4.1 Zone I (Inner Source.61.4.2 Zone II (Outer Source Protection) .71.4.3 Zone III (Source Catchment) .7.1.5 General UST M. .7.1.6OthercurrentSTv.8.approach.1.6.1 HS(G) 146: Conceptional.81.6.2 HS(G)146: Risk evaluation and assessment. .9Applicability.HS(G)146:General1.6.310.2. PRODUCTDESCRIPTION.10.2.1 &&i&i.10Table 1. Fuel Deliveries To Petrol Filling Stations (Tonnes). .102.2 Chemical.10star).2.2.1 Leaded Petrol (4112.2.2 Low Leaded Petrol .11.(Premiumunleaded).2.2.3 Unleaded Petrol1I.2.2.4 Super Unleaded Petrol122.2.5 Diesel (DERV). .122.2.6 Paraffin. .122.2.7 New fuels .122.3 General.132.4 1.132.4.1 Dispersion. .13.2.4.2 Absorption.13.2.4.3 Volatilisation.132.4.4 Biodegradation. .Figure I. Groundwater Contamination Schematic, Attenuation Mechanism and14Migration Characteristics. .15Table 2. Retardation Factor .15Table 3. Carbon content of hydrocarbon (K,). .17.PROCEDURESAND CONSIDERATIONS.3. ENGINEERINGOPTIONS,.17.3.1 Tank.17to tank types .3.1.1 Introduction.I8.Figure 2. Schematic of Underground Storage Tank and Fuel Line InstailationR&D Technical Report P5.i

CONTENTS3.1.2 Materials .Steel .Glass Reinforced Plastic (GRP) .Tank relining systems .3.1.3 Tank construction .3.1.4 Structural controls on tank installation .3.1.5 Groundwaterconsideration. .3.1.6 Steel tank protective systems .3.1.7 Overfill prevention. .3.1.8 Direct/off set fills and vent pipe .3.2 PiDew ork .to pipeline types. .3.2.1 Introduction3.2.2 Materials .3.2.3 Pipe installation. .Steel .GRI? .Plastic .Secondary containment .3.2.4 Pipe connection methods .3.2.5 Check valves .3.2.6 Vaulting/sumpsTank chambers .Dispenser sump. .manifold chambers. .Below ground offset fill chamber/pipe.3.2.7 Off set fills3.2.8 Vent lines .and pipe failure .3.2.9 Deformation.3.3 Otherenglneerlng3.3.1 Surface sealant .3.3.2 Tank vaults .3.3.3 Drainage .3.4 Monitoring3.4.1 Tank gauging .Table 4. Class of Detection Monitoring Equipment .Static leak detection .Continuousstatistical leak detection. .Automatic wet stock reconciliation .3.4.2 Interstitial monitoring .wells .3.4.3 Monitoring3.4.4 Testing .3.4.5 Line testing .3.4.6 Test timetable .3.5 Site4. RECOMMENDEDCONTROLENGINEERINGMEASURES IN RELATIONTOGROUNDWATERPROTECTIONZONES .4.1 Groundwater4.1.1 Local soil cover, topography and drainage. .4.1.2 Site geology and hydrogeologicalregime .4.1.3 Groundwaterand surface water vulnerability .4.1.4 Nature of local abstractions. .4.1.5 Potential pollutant travel time. .R&D Technical Report P5.ii191920‘0‘1212223.23.23‘3.23‘424.2 �9303030.3 13232323232333434343535353535.3636

.4.2 Engineerine.4.2.1 Tank installation .4.2.2 Pipework installation .4.2.3 Other engineering componentssystems.4.2.4 Monitoring and testing4.2.5 Site maintenance. .(redevelopments)4.2.6 Historical considerations.4.3 *otection.4.3.1 Tank installation4.3.2 Pipework installation .4.3.3 Other engineering componentssystems.4.3.4 Monitoring and testing4.3.5 Site maintenance. .(redevelopments)4.3.6 Historical considerations.’.*tsfo-.4.4 Eneineerine4.4.1 Tank installation .4.4.2 Pipework installation .4.4.3 Other engineering components4.4.4 Monitoring systems .4.4.5 Site maintenance. .(redevelopments)4.4.6 Historical considerations5. DECISIONINGSTRATEGY SUMMARY .5.1 BUST Installation. aspects and options. .5.1.1 Control engineering considerationsProtection Zones. .5.1.2 Groundwater5.1.3 Scoring of options . target scoring ranges .5.1.4 Engineering considerations.5.1.5 Minimum installation requirements.5.2 ADDiicationratineDroce&.5.3 O ther. .5.4 mTable 5. UST Installation Guidance Matrix .6. APPENDICES.6.1 -information- Kev w.6.2 ListSite A. Southern England. .Site B. North West England. .Site C. West Midlands. .Site D. Northern England. .Site E. Central England. .!. .Site F. Central England. .Site G. Central England .6.3 ManufacturersR&D Technical Report P5. 4040.4040404141414242.434646464646464646474748

EXECUTIVE SUMMARYProposed installation of underground storage tank (USTs) within groundwater protection zones(GPZs) has led to some conflict between the EA and developers in the past. Although standards forpetrol filling stations are clearly set out in HSE document HS(G)41, no specific internal guidance hmbeen available to EA staff with regard to the application of control engineering measures in USTinstallation so as to protect the groundwater environmentand, in particular, GPZs.This document will enable the EA to develop a more consistent approach to UST planning reviewpolicy. Specifically, it aims to provide guidance which will enable assessment of the groundwaterpollution risk posed by proposed UST installations through consideration of the hydrogeologicalregime and an appreciation of the various levels of protection which can be afforded by the currentcontrol engineering measures available.As an introduction,Section 1 of the document gives an overview of relevant legislation currently inplace and the existing EA groundwater protection policy including definition of the three GPZs (I, II,III). A review of current UST planning policy and installation guidelines available through otherregulatory bodies, including the HSE, are also discussed.Section 2 describes the specific fuel products typically stored in USTs on petrol filling station sites(leaded/unleadedspirit, diesel, paraffin, etc.). Chemical composition and physical properties of theindividual fuels types are discussed in some detail together with general hazard information. Fueldegradation and migration characteristics are then dealt with through consideration of the differentJttenuation mechanisms (dispersion, absorption, volatihsation and biodegradation) and variations inretardation factors within the subsurface aquatic environment.The importance of physical andchemical variation in both the subsurface environment(bulk density, porosity and organic content)and individual fuel types is demonstrated, These parameters act in unison to control the effectiveretardation factor and therefore the velocity of fuel migration within the subsurface.The engineering aspects of a petrol filling station are described in Section 3 with the various availableoptions, procedures and considerations being presented for specific operational components (tanks,pipework, monitoring/testingsystems). For tank, the different types are introduced(single/double/triplecompartment) along with constructionmethods and materials (single/doubleskin steel, glass reinforced plastic). For pipework (including dispensing, vent and off-set fill lines),types, materials (steel, GRP, plastic) and installation methods are covered. Information on protectiveand preventive engineering measures is also provided for both tank and pipework which includessecondary containmentmeasures, under pump check valves and vaulting. A sub section covers leakdetection, monitoring and testing systems (e.g. interstitial monitoring of double skinned tanks Jndlines).Having introduced the available engineering options and procedures, the recommended controlmeasures for each of the three designated GPZs are presented in Section 4. As an introductionto thissection, the factors controlling GPZ determinationare briefly reviewed. The crucial elementsconsidered include local soil conditions, geology, topography/drainagecharacteristics,hydrogeological regime and groundwater vulnerability.In addition, the importance of proximity tonearby surface

Proposed installation of underground storage tank (USTs) within groundwater protection zones (GPZs) has led to some conflict between the EA and developers in the past. Although standards for