TECHNICAL GUIDANCE NOTES TGN/1.5 DESIGN, COMMISSIONING, DECOMMISSIONING AND RECOMMISSIONING OF PETROLEUM RETAIL SERVICE STATIONS

Transcription

1 TECHNICAL GUIDANCE NOTES TGN/1.5 DESIGN, COMMISSIONING, DECOMMISSIONING AND RECOMMISSIONING OF PETROLEUM RETAIL SERVICE STATIONS JUNE 2016

2 Contents 1. Introduction Disclaimer Petroleum Retail Service Station Objective Scope Availability Legal Requirements Service Station PPGs Design and Construction...15 Design General Site Selection Site Plan Storage Tanks Pipework Dispensing Systems Delivery Areas Forecourt Surface Quality Drainage Systems Leak Detection and Wetstock Monitoring Systems Air Emissions Vehicle Fueling Construction...21 General Storage Tanks Installation Page 2

3 Vents Filling Connection Piping Fuel Dispensing System Commissioning...27 General Receiving the First Delivery of Fuel Decommissioning...28 General Permanent Decommissioning Making Tanks Safe In-situ Temporary Decommissioning Filling with Water Partially Filling with Water or Diesel Filling with Hydroscopic Foam After Tank Removal Dispensers Interceptors Drainage Subsurface Sampling Waste Management Recommissioning Records Environmental Risk Assessment...34 Hazards Vapor Releases Petrol to Soil Petrol to Groundwater Page 3

4 USTs Secondary Containment Requirements General Containment Volume Containment Construction Overfill Protection Separation of Materials Containment Drainage Other Requirements and Suggestions Risk Assessments References Contacts...40 Page 4

5 Acronyms Acronym ATG COP ERC ESD GRP KEBS KS NFPA OWS PIRP PPG PVR SOPs SUDs UST VOC Description Automatic Tank Gauging Codes of Practice Energy Regulatory Commission Emergency Shut Down Glass Reinforced Plastic Kenya Bureau of Standards Kenya Standard National Fire Prevention Association Oil Water Separator Pollution Incident Response Plan Pollution Prevention Guidelines Pressure Vacuum Relief Standard Operating Procedures Sustainable Drainage Systems Underground Storage Tank Volatile Organic Compounds Page 5

6 Terminology Terminology Automatic Tank Gauging Bottoming Breathing Description Automatic Tank Gauge. Electronically operated system that automatically measures the level of product inside the UST. Removal of residual product from USTs prior to decommissioning. Emissions from or intake of air into tank due to ambient temperature and/or pressure effects or due to vaporization/condensation of product Chamber/Manhole A chamber in an UST. It might also contain pipes, valves, level gauges and other installed equipment. It is covered with a lid. Also known as sump, manhole, inspection well or maintenance well. Change Community Company Competent Person Containment Contractor Controlled Waters Codes of Practice Any modification other than replacement in kind. Those residing near to an operating location/tank truck route to whom our activity is easily detectable either visually, aurally or by another means. It also encompasses key decision makers or those having a significant influence over local opinion for the locality. Company within the meaning of the Cap. 486 of Companies Act Means a person with enough practical and theoretical knowledge, training and actual experience to carry out a particular task safely and effectively. Means to prevent loss of liquid product in the event of a leak or spill Any company or individual that is under contract to provide services. Includes burns, rivers, estuaries, canals, lochs, ponds and groundwaters. Codes of practice state ways to manage exposure to risks. If a code of practice exists for a risk at the workplace, the operator must: Do what the code says; or Adopt another way that identifies and manages exposure to the risk; and Page 6

7 Terminology Danger Dipstick Dispenser Double Skin Drop Pipe Emission Emergency Shut Down Evaporation Facilities Fill Pipe Flow Rate Forecourt Fuel Delivery Area Gauging Device Groundwater Hazard Hazardous Area Description Take reasonable precautions and exercise due care. Risk to the environment, health, life, person or property of anyone from pollution arising from operation and maintenance of petroleum facilities A measuring rod to determine the level of product inside a storage tank and is used for taking measurements manually Equipment used for transferring product from the UST to the customer s vehicle Tank or pipe that has two separate walls. Fill pipe fitted vertically inside tank and reaching to the bottom of the tank, designed to reduce splashing during filling The episodic or ongoing release of materials to the environment (air, water or land). Emergency Shutdown are critical safety devices that shutdown operations or processes during emergencies Conversion of a liquid to vapor without necessarily reaching the boiling point Physical equipment and/or plant, including large mobile equipment, involved in the performance of affiliate operations. A pipe either fitted to a tank or inserted into a tank to permit filling Litres per minute An area used to fill customers vehicles. Pump islands and dispensers are located here. An area used by road tankers while filling USTs. The top parts of fill pipes and/or filling sumps are located here. Device for the measurement of liquid level in a tank Water that is below the surface of the ground in the saturation zone, i.e. below the water table. A potential source of serious harm to people, property or the environment. An area in which there exists or may exist an atmosphere containing flammable gas or vapor in a concentration capable of ignition Page 7

8 Terminology Hydrocarbon Improvements Incident Kenya Standard Management Managers Monitoring Well Near Miss Occupational Health Off-set Fill Point Operation Overfill Protection Permit Petroleum Description Chemical compounds containing carbon and hydrogen which are produced by the refining of crude oil and which are generally used as fuels. Physical additions made during the lifetime of a facility or site. A specific event or extended condition that has a significant unwanted and unintended impact on the safety or health of people, on property, on the environment, or on legal/regulatory compliance. Specification or Code of Practice declared by The Standards Council under section 9 of the Standards Act Site management is typically the most senior level of operations management working on site. Personnel with line management or supervisory responsibilities. A well for observing the conditions in underground spaces. An unintended or unwanted event or circumstance which under slightly different conditions would have resulted in an incident. Process encompassing all activities addressing workplace health hazards and employee health. It includes identification, evaluation, and control of health hazards; monitoring of worker exposures; communication of health hazards knowledge, determination of employees medical fitness to do their work and providing or arranging for medical services necessary for the treatment of occupational illnesses or injuries. A filling point on which connections for the hose of the delivery vehicle is at some distance from the tank Any activity involving the production, manufacture, use, storage or movement of material. Also, the utilization of resources by a unit to produce an output. Equipment that halts the transfer of product from a road tanker to an UST when the tank is full. Authorization granted to a person to enable the carrying out of any activity in the energy business, where a license is considered onerous "Petroleum" includes petroleum crude natural gas and any liquid or gas made from petroleum crude, natural gas, coal, Page 8

9 Terminology Pollution Prevention Program Practice Pressure Vacuum Relief Project Pump Island Quality Recommendations Recommissioning Replacement Inkind Retail Service Station Description schist, shale, peat or any other bituminous substance or from any product of petroleum crude, natural gas and includes condensate Pollution prevention describes activities that reduce the amount of pollution generated by a process. The pollution prevention approach seeks to increase the efficiency of a process, thereby reducing the amount of pollution generated at its source. Although there is wide agreement that source reduction is the preferred strategy, some professionals also use the term pollution prevention to include recycling or reuse. Approved method or means of accomplishing stated tasks. Pressure/Vacuum Relief Valves (Breather Valves). Direct acting pressure/vacuum relief valves are special types of relief valves which are specifically designed for tank protection. The range includes pressure only, vacuum only and combined pressure/vacuum valves, all available with flanged outlets or vented to atmosphere. Pressure / vacuum relief valves are used extensively on bulk storage tanks, including fixed roof tanks with floating covers, to minimize evaporation loss. The valves prevent the buildup of excessive pressure or vacuum which can unbalance the system or damage the storage vessel A planned undertaking with a specific objective and defined scope. Includes new construction and additions or revisions to existing facilities. Base for the dispenser The ability for a product, service or activity to meet or exceed requirements. Potential solutions to findings or observations. Recommissioning is essentially the same process as commissioning, but applies to existing facilities and provides a systematic approach for discovering and solving problems associated with facilities operation and maintenance procedures. Replacement which is essentially identical to the original and satisfies all relevant standards and specifications. Premises where petroleum is stored in bulk in one or more tanks and dispensed to consumers for their own use Page 9

10 Terminology Risk Risk Assessment Road Tanker Shell Site Standard Operating Procedures Splash Loading Standard Street Suction Pipe Sustainable Drainage Systems Third Party Ullage Underground Storage Tank Vapor Pressure Vapor Recovery Description Risk is a function of the probability of an unwanted incident and the severity of its consequences The process by which a risk analysis is conducted and results used to make decisions, either through relative ranking of risk reduction strategies or through comparison with risk criteria or other standards of acceptability. Petroleum Tank Truck that delivers product to the site. The walls of a tank The place where something was, is or is to be located. May be a marketing location, a refinery, gas plant or offshore platform. Standard Operating Procedures are documented series of steps to be carried out in a logical order for a defined operation or in a given situation. Filling of a tank resulting in excessive splashing and vapor generation A defined product or result. Includes requirements for quality, content, review and conformance with regulations. Way, road, lane, square, court, alley, passage or open space, whether a thoroughfare or not, over which the public have a right of way, and also the roadway and footway over any public bridge, or causeway Pipe for transferring product from the UST via a dispenser to customer s vehicle. SUDS are a sequence of water management practices and facilities designed to drain surface water in a manner that will provide a more sustainable approach than what has been the conventional practice of routing run-off through a pipe to a watercourse. A contractor providing services in accordance with specifications, terms and conditions documented by a contract agreement and signed by both parties. Free space above the liquid in a tank Underground Storage Tank for fuel, usually made of steel and installed underground. Capacity usually 10,000 60,000 Litres. Pressure exerted by a volatile liquid Vapor Recovery System is the process whenvapor is Page 10

11 Terminology System Vent Pipe Description collected and returned to a road tanker when filling the UST. A pipe provided for the USTs venting system. Necessary to prevent tank distortion due to variations in internal pressure resulting from the normal operational filling and emptying Page 11

12 1. Introduction 1.1. The Pollution Prevention Guidelines (PPGs), herein referred to as guidelines, are intended to help those who design, construct, commission, decommission and recommission Petroleum Retail Service, herein to as site They have been produced by the Energy Regulatory Commission (ERC). Contact details can be found at the end of these guidelines. 2. Disclaimer 2.1. The information contained in the PPGs is not intended to be prescriptive, or to preclude the use of new developments, innovative solutions or alternative designs, materials, methods and procedures, so long as such alternatives provide a level of control over pollution appropriate to the risks identified The guidelines are provided for information and while every reasonable care has been taken to ensure the accuracy of its contents, the ERC cannot accept any responsibility for any action taken, or not taken, on the basis of this information. 3. Petroleum Retail Service Station 3.1. The major environmental risks at a site involve release sources which endanger air, soil and water Volatile Organic Compounds (VOC) are responsible for pollution of the air, soil and water and particularly hazardous are chemical additives which are very toxic and harmful to groundwater Professional interventions using appropriate technology and skills can protect the environment, diminish the degree and extent of damage, alleviate and control the worst aspects of pollution If an emission stream is not generated, it does not have to be cleaned up or controlled. To implement this simple philosophy it is necessary to raise the level of understanding of personnel to ensure that environmental performance meets legal and safety requirements The overall aim of the guidelines is fuel containment integrity, from the tanker offloading point to the dispenser nozzle through site design, commissioning, construction, decommissioning and recommissioning. Page 12

13 4. Objective 4.1. Every site has the potential for releasing polluting agents into the soil and possible causes for the release include: a. Damaged wall of UST b. Leaks of underground pipe c. Leaking or broken dispenser d. Overfill when road tanker is filling UST e. Overfill when customers vehicles are refueled f. Non fuel proof pavement of refueling area or forecourt g. Lack of drainage and/or OWS at the fuelling area or forecourt h. General damage to fuel equipment and facilities 4.2. The release sources of pollutants into water are similar to those sources into soil. Removing pollutants from water is more costly and difficult The purpose of the PPG is to provide straightforward guidance on good practices for design, construction, commissioning, decommissioning and recommissioning of sites to prevent releases and pollution agents from hydrocarbons. 5. Scope 5.1. The PPGs: a. Provide technical information on the storage and dispensing of petroleum products at sites to which the general public have access. b. Cover civil and mechanical installation issues for design, construction, commissioning, modification and decommissioning of sites. c. Provide information aimed at minimizing the risks to health and to the environment. d. Describe good practice and certain legal requirements, particularly those applicable in new sites and existing sites that are to be modified/refurbished The PPGs do not: a. Cover the detailed procedures for assessment of risk. b. Provide information on operational procedures. c. Cover all potential configurations/types of installations, some of which will have site-specific risks associated with them. Page 13

14 5.3. The PPGs are relevant to sites which store hydrocarbons for dispensing purposes and contain advice specifically aimed at the following persons with respect to sites: a. Owners b. Persons involved in operational management c. Persons involved in design and construction d. Persons involved in decommissioning e. Persons responsible for abandonment 5.4. The persons responsible for complying with the guidelines might not necessarily possess appropriate knowledge and expertise and are urged to consult relevant guidance or seek expert advice The PPGs outline good practices which should be adopted by a site to prevent pollution during: a. Design b. Commissioning c. Construction d. Decommissioning e. Recommissioning 5.6. For each of these lifecycle stages, the PPGs highlight the potential risks to air, soil and groundwater and outline the types of good practices to be developed and followed. 6. Availability 6.1. The PPGs are published by the ERC and will be made available. 7. Legal Requirements 7.1. The Regulatory Framework and useful guidance and publications are given at the end of the PPGs. Page 14

15 8. Service Station PPGs 8.1. The PPGs apply to sites, the degree and means of environmental protection will vary for each individual site In determining what is required for individual sites, it is necessary to take into account the following: a. Location and environmental setting of the site b. Age of the site c. Storage and throughput volumes of the site d. Practical engineering options and control mechanisms e. Likely costs and benefits of upgrading the sites Whilst the best practicable environmental options should be adopted, it is not expected that all sites would meet or exceed the highest degree of engineering design or operational and management systems. However, all sites are expected to meet the minimum industry standards for the selected degree of engineering. 9. Design and Construction 9.1. Whilst no loss of product can occur during the design and construction phases, failure to consider potential environmental risks of the process could ultimately result in a significant pollution incident. Design General 9.2. Factors which should be considered during the design to minimize the potential loss of product and pollution include: a. Environmental sustainability of the site and measures to be incorporated b. Siting of the site c. Storage tanks (tank design, tank contents, materials used to construct tanks and secondary containment) d. Pipework and pipe trenches Page 15

16 e. Corrosion prevention systems f. Fuel delivery and dispensing systems g. Delivery facilities (e.g. overfill prevention, drainage of tanker standing area) h. Site drainage systems (including interceptors) i. Leak detection and environmental monitoring systems 9.3. When designing, emphasis must be placed on hazard prevention rather than risk management The design shall incorporate adequate measures to respond to emergencies such as fire, spills, robberies etc 9.5. Design shall comply with KS2506 with regard to space requirements for proposed tier Site Selection 9.6. Compliance with EMCA, 1999, EIA Regulations, KS2506 and other applicable regulations and standards 9.7. As a minimum, the UST shall be located 5m from the property boundary line in accordance to NFPA Area requirements should be as provided under KS During site selection, consideration should be given to: a. Proximity of the installation to water sources b. Historical site activities c. Land Use d. Zoning Requirements e. Corrosive nature of soil f. Groundwater conditions Site Plan When it is proposed to construct or redevelop a site or where it is proposed to make material alterations to a site, a drawing of the Site Plan should be prepared at a scale of 1:500 detailing the following: a. Position of USTs and associated pipework including fill points, monitoring wells, pumps, dispensers and road tanker offloading positions b. Buildings situated within Metres of USTs, pumps and vent pipes as per NFPA 30. Page 16

17 c. Details of forecourt surface water and other drainage including vehicle washing facilities and associated drainage. d. Site levels and details of surface finishes e. A drawing to the scale of 1:50 showing in detail the construction and method of installation of USTs and monitoring wells On completion of construction of the site or redevelopment, as built drawings must be prepared showing the pipe work runs as actually installed. Storage Tanks Sites can make use of different types of UST: a. Single skinned mild steel tanks b. Single skinned glass reinforced plastic (GRP) tanks c. Double skinned steel tanks d. Double skinned GRP tanks e. Double skinned composite tanks Traditional practice has been to install single skinned steel tanks surrounded by concrete. The concrete is not intended to contain product lost from the tank, but might delay its release into the surrounding ground if it is not cracked or jointed Double skinned tanks have an advantage over single skinned tanks. Two walls would have to be breached in order for leakage to occur and the interstitial space can be monitored to provide warning of a leak before product is lost to the environment Double skinned tanks should be installed on any new or redeveloped sites Where steel tanks are to be utilized, these should be protected using anticorrosion paint in conjunction with effective leak detection and cathodic protection UST should be installed with electronic or mechanical overfill protection devices and ATGs for measurement of the level of product Sites should install a suitable leak or spill detection system Fugitive vapors due to breathing losses from USTs shall be released to the atmosphere through vents located at least 3 metres above the roof level. Pipework The design of piping shall be suitable for expected working pressures, temperatures and structural stresses and comply with relevant international standard. Page 17

18 9.21. Any material used in the construction or installation of piping shall be suitable for the conditions of use, in particular: a. It shall be compatible with petroleum products with which it will be in contact b. It shall be resistant to heat to which it may be exposed c. Where subject to corrosion, it shall be sufficiently resistant to ensure acceptable life Pipework has normally been constructed from steel laid in a concrete surround. Good practice would be to utilize double skinned pipework Steel pipework should have adequate protection against corrosion particularly of mechanical or welded joints Plastic pipes are permeable to hydrocarbon vapors and it is recommended to use pipes manufactured from specially developed thermoplastic composites or plastic/metal composites. Other advantages of composite pipes are flexibility, and a reduced need for joints Such pipework should be laid in granular material or sand in order to protect it from damage by larger stones or uneven settlement Steel and GPR Pipework should always be connected to tanks or dispensers using flexible connections to allow for relative movement and ensure no resulting load is transmitted to the pipework Pipework should be installed with secondary containment to retain leaks from fuel carrying pipes Double skinned pipework with interstitial monitoring protects the environment by alerting operators to leaks before product escapes into the surrounding soil Flexible tubing, piping or hose may be used only on condition that: a. The use of such tubing is unavoidable because of the need to provide for movement or to reduce the effect of vibration b. The tubing is of flexible metallic, metal-reinforced or armored construction suitable for the working pressure, temperature and product handled. Dispensing Systems The dispenser should be located in such a way that it cannot be easily damaged Dispensers should be fitted with nozzles and under pump-valves to prevent uncontrolled release of product Sites should have impact check valves at the base of the dispensers using pressure delivery and shear valves at the base of dispensers using suction delivery Page 18

19 9.33. Protect dispensers by mounting on properly designed plinths and/or provide safety barriers Use breakaway couplings on fuel delivery hoses Delivery Areas A delivery area should be designed such that there is sufficient room for the delivery vehicles to unload without disturbance. The area should be impermeable to hydrocarbons The delivery systems should be designed to prevent spillages and overfilling of tanks Overfill protection involves limiting the amount of fuel that can be delivered into the storage tank by the use of automatic shut off valves or electronic alarms. Forecourt Surface Quality Areas susceptible to contamination, e.g. pump islands or tanker offloading points, should be impermeable to hydrocarbons and should not allow seepage through or below the surface. Drainage Systems Drainage systems should be designed such that surface spillages are contained and there is no direct loss to ground or to surface watercourses or soakaways for surface water drainage. This involves the use of low permeability surfacing in areas which could be contaminated with product All surface water run-off and spillages should pass through an OWS Treatment System The drainage system including hardstanding and drainage pipework should also be constructed of materials, which are resistant to attack by hydrocarbons The drainage pipework should be sized to suit the storm return requirements to the location and capable of transporting a spillage from the tanker standing area at the rate of at least 15 Litres per second To prevent the potential for any leakage from below ground apparatus to enter the drainage system, the drainage system is best located so that it is not adjacent to USTs and dispensing pipework All roof drains which collect clean, uncontaminated water should be routed to bypass the OWS to avoid reducing the capacity of the unit to contain spills. Page 19

20 Leak Detection and Wetstock Monitoring Systems The most effective leak detection and wetstock monitoring systems detect a failure before loss of product into the soil and are normally used in conjunction with double skinned systems In wetstock monitoring, errors can arise as a result of miscalibrated dispensers and can result in the masking of leaks. It is important that dispensers are annually calibrated. Air Emissions The design of new sites should include the installation of vapor recovery pipework and manifolds and pressure/vacuum valves on UST vents The design shall comply with KS2506:2014 or any other international standards With vapor control equipment, the vapor vents from the UST are connected back to the delivery tanker To stop the vapor going out to the atmosphere, the tank vents are fitted with pressure/vacuum valves (P/V Valves) which maintain a small back pressure in the system and together with the negative pressure in the delivery tanker encourages vapor to flow back to the tanker compartment Changes to an existing installation will require the: a. Addition of vapor return pipework system to route the vapor back to the road tanker and modifications to the UST vent system including a vent control device. b. Provision of a vapor connection at the filling point for returning vapors to the road tanker c. Provision of vapor transfer hoses The condition of the existing fill and vent pipework installation should be checked in order to determine which design options are suitable for existing sites and if leaks or restrictions in liquid systems or vapor vent exist. Vehicle Fueling For new sites: a. A special nozzle collects vapor from the car fill pipe instead of allowing it to vent to the atmosphere. b. Vapor is returned to storage or vented via a filter. c. A vacuum pump may be situated in each dispenser housing or there may be a single central pump at a remote location For existing sites, following changes are required to installations: Page 20

21 a. Use of a special refueling nozzle and ancillary fittings b. Introduction of a vapor return hose on the dispenser connecting the nozzle to the vapor piping c. Additional pipework to return vapor from the dispenser to the storage tank d. Additional equipment installed within the dispenser or at a remote location 10. Construction General Construction shall only be commenced after obtaining a Construction Permit from ERC in accordance with the Energy Act, Loss of product could arise during the operation as a result of inadequate construction methods Incorrect construction could also result in unsealed joints or areas of potential future weakness, such as loss of integrity of hardstanding or catchpits Factors during construction that influence the future integrity of the operational site: a. Tank and pipework handling b. Ground preparation c. Installation procedures d. Incorrect site layout and set-up e. Supervision and quality control f. Commissioning procedures Good quality construction is essential and should be carried out by suitably experienced and qualified persons and approved by the National Construction Authority (NCA) for the class of works. Contractors are expected to use safe working practices when carrying out work at the site The quality of all materials and equipment should be checked prior to installation or use and strict quality assurance maintained during construction Rigorous inspection and checking of a completed storage system is vital. Page 21

22 Storage Tanks Installation Tanks for all classes of petroleum at a site shall be installed underground and shall be designed, constructed, installed and tested to meet KS 1969 (2006) - The petroleum industry - The installation of underground storage tanks, pumps / dispensers and pipe work at SERVICE STATIONS and consumer installations - Code of Practice All underground tanks shall be installed in accordance with the following requirements: a. The road surface above the UST shall be of reinforced concrete of the thickness necessary to support itself and any superimposed loads, but not less than 150mm. b. The depth from the road surface to the top of the tank shall be not less than 450mm. c. Each access pit shall be fitted with a cover that is water tight or raised above the level of the surrounding ground to prevent the entry of surface water and of strength sufficient to withstand any superimposed loads. The strength of such a cover shall not be inferior to those of 5mm low carbon steel The distance of the UST to any property boundaries and foundations shall be not less than 5m and 1m respectively as provided in NFPA30 and KS The UST and its associated piping shall be protected from corrosion by: a. Protective coating or wrappings b. Cathodic protection c. Corrosion-resistant materials of construction Prior to placement in the ground, all tanks and pipework must be kept in a safe environment to avoid damage due to punctures and to protective coatings. Care must also be taken to prevent damage during installation Good foundations are required. In addition to their physical competency, founding strata must be assessed for corrosion characteristics, which might affect structural integrity of below ground equipment All excavations should be level and compacted to form sound founding strata and prevent potential differential settlement which might damage tank structure and pipework. The ground preparation should be appropriate to the type of tank and pipework being installed. Page 22

23 Vents Each tank shall incorporate a vent to atmosphere for the vapor space above the liquid. Page 23

24 The size of the vent shall be such that pressure or vacuums resulting from filling, emptying or atmospheric temperature change, will not cause stresses in excess of the maximum design stress for the tank and shall have a minimum internal diameter of 38mm Any vent piping between the tank vent connection and the discharge point shall fall consistently back to the tank at a slope not less than 1 in A vent pipe shall not pass through building foundations but may be embedded in concrete, which is part of other building construction A vent shall not be run within a cavity wall but may pass through a cavity wall or through masonry which incorporates cavities, provided that it is in a sleeve which will prevent vapor gaining access to the cavities A vent pipe may be either embedded in a concrete slab or laid in the earth. If the vent pipe is laid in the earth, it shall be: a. Located not less than 300mm below ground level b. Surrounded by clean washed sand, or provided with equivalent c. Corrosion protection d. Suitably protected if the area is subject to vehicular traffic The vent pipe shall be located or protected so that it is not liable to damage resulting from normal activities and shall be vapor-tight throughout its length All UST or compartment in a tank shall have a separate individual vent pipe The discharge point of a vent shall comply with the following requirements: a. The location, direction and velocity of discharge shall be such that venting vapor will not cause danger to the surrounding. b. The vent discharge point shall not be less than 3.0m from any boundary and opening in a building. c. The vent shall discharge into open air and vent discharge point shall be located not less than 4m above ground level The discharge end of a vent shall be protected from the ingress of foreign material by a protective cage of fitting and shall discharge only vertically upward to disperse vapors. Filling Connection The filling connection to a storage tank, which is filled from a tank vehicle, shall incorporate a vapor-tight connection A cap or cover with lock shall be provided for the filling point. Page 24

25 Means shall be provided to prevent accumulation or abnormal discharge of vapor during refilling by having a vapor recovery system The location of the filling point for UST to be filled from a tank vehicle shall comply with KS 1969 as follows: a. The length of hose required to connect a tank vehicle to the filling point shall not exceed 5m b. The filling point shall be protected from accidental or physical damage. c. Guardrails or necessary measures shall be installed to prevent damage by collision The filling point for USTs containing petroleum shall be in open air at least 3.0m from any opening into a building and boundary. If a distance of 3.0m cannot be complied, a vapor barrier made of non-combustible material shall be used and shall not be less than 500mm high above the center of the filling point inlet The vapor barrier must be at least 1m from the boundary line. The distance measured in a horizontal plane around the end of any vapor barrier must be 3m from the center of the outer most filling point inlet to the building and boundary The edge of the tank vehicle designated parking area for refilling shall be at least 3m from any opening into any building and boundary. Piping Dispensing pipework and delivery apparatus should be installed to prevent leakage The following installation considerations shall be taken into account for piping: a) The layout shall take into account the needs for all operating access and shall ensure that any access way is not impeded. b) The number of joints should be kept to a minimum. c) Supporting and fixing shall be secure and the piping shall not be unduly exposed to mechanical damage Provision shall be made wherever necessary, for the expansion or contraction of the piping and its contents Any buried piping shall be protected from superimposed loads, ground settlement etc Piping shall be painted and/or marked in a manner sufficient to permit ready identification of its contents. Page 25

26 Fuel Dispensing System Dispensing units at a site shall be located in the open air where they will be adequately ventilated. These shall be located such that all parts of the vehicle being served will be on the premises and shall be sited not less than 6m away from any building, public roadway or boundary A clearly identified and easily accessible switch or circuit breaker (centralized ESD) shall be provided at a location remote from the dispensing devices, including remote pumping systems, to shut off the power to all dispensing devices in the event of an emergency and shall not be less than 6m or more than 15m from the dispenser A sign incorporating the wordings "EMERGENCY CUT-OFF" shall be provided in the vicinity of the cut-off switch Petroleum shall be transferred from USTs by means of fixed pumps designed and equipped to allow control of the flow and prevent leakage or accidental discharge A control shall be provided such that the pump will operate only when a dispensing nozzle is removed from its bracket or normal position with respect to the dispensing unit and the switch on this dispensing unit is manually activated This control shall also stop the pump when all nozzles have been returned, either to their bracket or to the normal non-dispensing position The dispensing unit and its piping shall be mounted on a concrete island. Each island shall rise not less than 150mm above the surrounding ground level and shall extend not less than 300mm on both sides of the dispensing units and at least 500mm from the dispensing unit to the edge of the base measured longitudinally Hose length at service station shall not exceed 5m. When not in use hose shall be secured so as to protect it from damage The nozzle through which fuel is dispensed to a vehicle shall be such that it automatically closes when the fuel tanks of the vehicles are full A rigidly anchored emergency shutoff valve designed to close automatically in the event of a severe impact or fire exposure shall be properly installed in the supply line at the base or inlet of each dispenser. Page 26

27 11. Commissioning General Prior to the site becoming operational, measures should be taken to ensure that all valves, fill pipes, vent pipes and monitoring wells are readily identifiable and cannot be confused Prior to operation the following checks should be carried out: a. Testing of manhole chambers for integrity b. Drainage systems, including separators completed and tested c. Separators to be charged with water to make them operational d. Emergency equipment installed and operational e. Tanker stands and forecourt areas completed f. All tanks, pipework, dispensers and pressure relief systems to be tested, to demonstrate integrity and safety Other commissioning procedures include the following: a. Safety signs and notices in place b. Emergency equipment in place and working correctly c. Fill points, tanks, pipework and dispensing equipment clearly marked Where drainage systems have been installed, they are connected, leak tested and free from debris and the interceptor charged with its water seal. Receiving the First Delivery of Fuel The first delivery of fuel must be carried out with great care to avoid the release of large amounts of vapor through the fill pipes openings of the tanks A safe method of introducing fuel into the tanks is to individually unload 1,000 Litres of fuel into one tank at a time until all tanks are charged with sufficient fuel to provide a seal at the drop tube After this stage of the commissioning procedure is completed the remainder of the product can be offloaded in the normal manner. Page 27

28 12. Decommissioning General Decommissioning activities range from the complete closure and removal of a site as a whole, to the replacement of individual tanks or lengths of pipework Factors to be considered in assessing pollution risk during decommissioning include: a. Decommissioning methods will result in the release of product to the ground b. Decommissioning methods will result in product remaining insitu in below ground structures (i.e. tanks, pipework, and drainage) c. Below ground equipment will remain after decommissioning Persons involved in decommissioning must be aware of and meet their obligations with regard to waste disposal. Permanent Decommissioning This includes the complete removal from site of USTs and associated pipe work or the making safe in situ: a. All lines should be drained back and then all residual product uplifted. b. All dispensers must be removed. c. Tank(s) and lines should be inerted, or alternatively cleaned and gas freed. d. Inerting must be maintained during excavation work. e. Cleaning and removal of OWS and connected surface water drainage system. f. Tank remains - inerted or gas freed pending disposal. Making Tanks Safe In-situ The making safe of tanks in situ is only acceptable where removal is not practicable and the tank is level within its excavation. This should be tested by placing a spirit level across the tank lid Tanks may be made safe by either: a. All residual products must be uplifted and tanks immediately filled. Page 28

29 b. Filling with lean cement slurry filling 20:1 sand/cement slurry having 175mm slump. The slurry is to be vibrated during pouring and the tank must be inerted. c. Hydrophobic foam filling to a compression appropriate for permanent decommissioning 22 tonnes/m². The tank should be filled until foam discharges through the temporary vent pipe and then a back pressure of 0.5 bar applied to ensure that the tank is completely filled. d. All lines must be drained back, purged and capped. If hydrophobic foam filling, all lines and vents should be foam filled. e. All vent pipes associated with the tank(s) should be dismantled and removed from the site. f. All notices referring to petroleum spirit storage where storage has ceased should be removed. g. Work to remove or make safe in situ must be carried out by a competent person. Temporary Decommissioning If sites are decommissioned temporarily, it is possible to leave product or water in tanks All monitoring procedures must be continued as if the site remained operational If for any reason monitoring cannot continue, the tanks should be emptied and made safe. Filling with Water Isolate the tanks and associated equipment from the electrical supply All pipe work except the vent pipe work should be drained and disconnected in the man way chamber of the tank Remove all residual petrol. (Bottoming the tank) Immediately fill the tank or compartment with water to a level where clear water appears at the disconnected pipe work openings Cap or blank off all openings to the tank or compartment The vent pipe work together with the flame trap outlet(s) remain connected to allow the tank to breathe Flush through and cap at each end all pipelines previously connected to the tank or compartment. Page 29

30 The filling/dipping pipes should be kept securely locked. All offset fill pipes to be adequately secured against unauthorized access, vandalism or inadvertent use All contaminated water must be disposed of with due regard to the environment Where the site is to be left unoccupied whilst being sold as a going concern, adequate steps should be taken to ensure risks from tampering or vandalism are reduced or eliminated. This may involve protection of the site by fencing off the site, or the removal or boarding up of dispensers. Monthly checks are still required to be undertaken Any tank that once contained petrol or its previous status is unknown, should be treated as an ex-petrol tank and completely water filled to avoid any possible build up of vapor No tank should be left empty between the operations of bottoming and water fill Water fill is not allowed indefinitely. Partially Filling with Water or Diesel Where a tank(s) are taken out of service pending a decision on its future, it may be rendered temporarily safe, provided adequate controls can be maintained: a. Remove residual petrol, bottom tank and ensure that the fill pipe is intact. b. Introduce sufficient water or diesel into the tank to maintain a liquid seal between the termination of the internal fill pipe and the tank vapor space. c. Fix suitable warning notice at the manhole. d. Introduce a regular inspection regime to ensure that the site is not interfered with and that the liquid seal is maintained at the fill pipe. Filling with Hydroscopic Foam All pipe work except the vent pipe work should be drained and disconnected in the manhole chamber of the tank. The tank should be bottomed It may be necessary to treat the bottom of the tank with a proprietary emulsifier to ensure, as far as possible that all residual petrol is removed The tank should be filled with hydroscopic foam generated on site, pumped directly into the tank and have a designed compressive strength of 15 tonnes/m2. Page 30

31 Tanks filled with hydroscopic foam can be reinstated by mechanical removal of the foam or by using a solvent and vacuum extraction method. After Tank Removal Once removed from the ground all tanks and pipework should be made safe for transport, e.g. by cold cutting to allow free venting It is good practice to remove tanks, pipework and dispensers, however if tanks are being left in-situ, they must be made safe Following bottoming and making safe, tanks should be filled with either: a. Sand and cement slurry b. Hydrophobic foam c. Foamed concrete. Dispensers May be made temporarily safe by being left in situ Dispensers should be electronically isolated, all suction lines drained back and flexible connectors disconnected Dispenser suction entries should be plugged off and the suction and vapor lines capped off in the under pump cavity Dispenser should be protected from vandalism by sturdy wooden encasement or other suitable material for short periods of time (6 months maximum) For Dispenser removed from site, the following measures should be undertaken: a. Isolate electrically, drain all suction lines and disconnect flexible connectors. b. Drain of residual petrol and purge with nitrogen. The suction entries should be placed in storage or dispatched for scrap. c. Cap off the suction line and any vapor lines in the under pump cavity. d. Infill the under pump cavity with a suitable backfill material. Interceptors Wherever practicable, OWSs should be removed for off-site disposal OWS Chambers should be emptied of all liquid and sludge contents by a Hazardous Waste Disposal Contractor The chambers should then be replenished with clean water. Page 31

32 For more details on design and use of oil separators in surface drainage systems see guidance notes PPG/1.2. Drainage Drainage systems that are to remain active should be modified to ensure that they do not present a significant migration pathway for pollutants to reach soil, groundwater or other controlled waters. Subsurface Sampling Once USTs have been removed, samples of soil and groundwater (if present) should be taken to check for subsurface contamination The samples will be analyzed for parameters for the type of product stored If soil or groundwater contamination is found, additional investigations should be carried to determine the need for remediation. Waste Management Tanks and pipework used to store hydrocarbons together with residual product, wastewater, sludge and decommissioning fill may be classified as hazardous waste If the tank has been used for the storage of flammable materials, then the operator must ensure that the waste disposal contractor is aware of all appropriate health and safety guidance. 13. Recommissioning Depends on whether it was out of action for a short period (12-18 months) for cleaning or pending modifications or site development For reinstatement following Short Term, a full visual inspection should be carried out and defects or omissions rectified or replaced as the case may be Normally, the testing necessary will be to prove the integrity of the tank lid gaskets and pipe work reconnections For reinstatement following Long Term (18 Months plus), the site should be risk assessed to establish whether there are adequate safeguards in place to control the risks of environmental pollution from the storage and handling of petrol. Page 32

33 13.5. Any tank made temporarily safe for a period of time will require leak testing before being brought back into use. 14. Records Records must be kept of how the site was built for future reference and records must include all built drawings of the site Records shall be dated and maintained during the life of the site and in a location where they can be retrieved quickly for emergency response. Page 33

34 14.3. Records shall include: a. Schematic Diagram of the USTs, pipework and pump layout b. Results of commissioning and installation work c. Schematic Diagram of surface water drainage system, including all gullies and the position of the Oil/Water Separator. d. Certificate for testing of the drain pipes e. Diagram of hazardous zones and types of zones f. As built plans/drawings plans detailing the whole site development g. Details of construction of tanks and methods of installation h. Certificate for testing of tank and/or leak monitoring system i. Details of construction of pipework and method of installation j. Details of class of leak detection system installed and commissioning certificate 15. Environmental Risk Assessment Hazards Petrol is a complex mixture of up to 240 individual hydrocarbons most of which have varying degrees of toxicity towards living organisms and plants If released at a site by spillage or leaks from tanks and pipes it may, in the absence of adequate controls, either soak into the ground directly or flow into drains or culverts In most cases some of the following types of petrol are adsorbed onto soil particles or held in the soil pores: a. Free petrol floating on the groundwater b. Petrol constituents dissolved in the groundwater c. Free petrol at impervious ground layers such as clay d. Petrol floating on surface water (i.e. rivers and lakes) e. Petrol constituents dissolved in surface water f. Free petrol in drains (in use or redundant) or underground voids g. Petrol vapors released from the above sources into the atmosphere or underground voids etc. Page 34