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Table of Contents
1. General
1.1 Description
This specification gives the minimum technical requirements for completely assembled LV switchboards and auxiliary components for service voltage up to 1 kV. Additional information for each individual case shall be given in the requisition.
1.2 Applicable Conditions and Regulations
1.2.1 All latest issue of the applicable standards of the country as stated in the requisition.
1.2.2 All other national and/or local regulations applicable to this type of work.
1.2.3 Badger's terms and conditions applicable to orders for field labor, if erection is part of vendor's supply.
1.2.4 Purchaser's 'conditions for construction services ', no. SC 00 SEC, ( if erection is part of vendor's supply ).
1.3 Site Conditions
Switchboards shall suit the site conditions mentioned in the requisition and withstand a corrosive chemical and refinery environment. The equipment will be located indoors or outdoors at a maximum ambient temperature of 40ºC and a minimum ambient temperature of - 10ºC, unless otherwise specified in the requisition.
1.4 Responsibility
1.4.1 The vendor shall be responsible for design, fabrication, inspection, testing, transportation and start-up of the switchboard, unless otherwise specified in the requisition.
1.4.2 The vendor shall supply a completely functional switchboard, complete with all accessories.
1.4.3 Purchaser shall only provide external cable connections of all incoming and outgoing cables to the switchboard.
1.5 Conflicting Requirements
In case of conflicts between the conditions and documents mentioned above or between them and the specification in hand, the severest requirements will govern. In case of conflicts between the specification in hand and the requisition, the requirements of the specification in hand and the requisition, the requirements of the requisition will govern.
Purchaser will not be obliged to check vendor's documents such as quotations, order confirmations, drawings, etc. Purchaser will review these in principle only. It will remain the responsibility of the vendor to manufacture the switchgear in accordance with this specification in a functional and workmanlike manner.
A deviation from the requisition ( of which this specification forms part ) will only be acceptable if vendor has specified in his quotation under the heading ' deviations from specification ' the requirements he cannot meet and Badger has accepted this deviation in writing before order award or in the order.
Nonconformance will be interpreted by purchaser as confirmation that manufacturer will comply in all respects with this specification and any subsequent extra costs shall be borne by the manufacturer.
1.6 The entire switchboard shall provide maximum safety to operating and service personnel. Even if this will require more provisions than prescribed by law, it shall be vendor's responsibility to include these provisions.
2. Installation at Site
2.1 Where site erection is part of vendor's supply, the following will be supplied by others.
2.1.1 All outgoing cables and the connections of these cables to vendor's equipment.
2.1.2 Civil provisions outside vendor's equipment. However, this applies only in case the necessary information has been transmitted by vendor to Badger within 4 weeks after placement of order ( see item 3.3 ).
Provisions required at a later date will be for vendor's account.
2.2 Transport and Off-Loading Facilities on Site
2.2.1 In general, cranes will be available on site for vendor's use for his own account and under his own responsibility.
2.2.2 Availability of cranes and/or other necessary equipment shall be checked with the Construction Superintendent or his representative on site at least 1 week before equipment arrives.
2.2.3 Transport from car, train or boat to the relevant station shall be carried out :
By vendor or by subcontractor of vendor with or without vendor's supervision.
By others, if specified in the requisition.
In all cases, transport, temporary protection of equipment ( in case unloading on the same day is impossible or because of weather conditions ), and/or other handling procedures shall be carried out under vendor's responsibility and for vendor's account. Parts of equipment damaged during loading, unloading and transport shall be replaced immediately free of charge and without delay of the final delivery time stated in the order.
Vendor shall remain responsible for transport and/or storage of his equipment till final written acceptance by the field representative.
3. Drawings and Data
3.1 Quantities of Drawings
Drawings and other technical data shall be furnished in the quantities specified in the purchase order.
Language on drawings will be stated in the requisition.
3.2 Drawings and Information to be Furnished with the Quotation
3.2.1 One-line diagram showing all relays, meters, transformers and control devices. The drawing shall indicate switch, breaker, contactor, relay ranges and settings.
3.2.2 Schematic diagrams of control circuits for each type of contactor unit, breaker unit and undervoltage time delay system.
3.2.3 Data indicating the breaking capacity of the contactors, breakers and fuses and current capacity of busbars.
3.2.4 A list of subvendors for all breakers, contactors, relays, switches, metering equipment etc. purchased from others.
3.2.5 Manufacturer's leaflets giving complete descriptions and curves of breakers, contactors, relays, special meters, fuses, etc.
Note: Thermal relay curves are required, to check whether Ex-e motors will be disconnected within their TE times.
3.2.6 Outline drawing showing overall dimensions, required aisle space and clearances, and location of major equipment. This drawing shall also show the position of potheads.
3.2.7 Front view drawing showing incoming feeder ( s ), tie, outgoing motor panels, meters, push button, protection relays, etc.
3.2.8 Sketch of the busbars ( if any ).
3.2.9 Approximate weight of each switchgear.
3.2.10 Bidder shall indicate in his bid whether back access is necessary.
3.3. Drawings and Data to Be Submitted for Approval after Order Award
3.3.1 Within 2 weeks after receiving order vendor shall submit following drawings :
All drawings as per item 3.2, however, brought in line with Company's certified requisition and comments received in the bidding stage.
3.3.2 Within 4 weeks after placement of order vendor shall submit the following drawings :
- Drawings showing all civil provisions to be made by others including cable holes etc. Drawings shall show weight of equipment.
Drawings showing construction of bus duct with detailed outline dimensions and details of flange to transformer and air barrier.
3.3.3 Schematic control diagram, now complete with terminal and wire numbers.
3.3.4 Fully detailed schematic and wiring diagrams of electronic and electromagnetic protection relays.
3.3.5 All documents shall be marked with purchaser's order number.
3.4 Drawings and Data to Be Submitted for Construction
Within 2 weeks after the drawings and data as per item 3.3 have been returned to vendor, vendor shall re-submit same drawings properly corrected to purchaser.
3.5 Instructions
8 weeks before the delivery date indicated in the purchase order, vendor shall supply installation instructions. Immediately after testing in the factory vendor shall supply the number of operating and maintenance manuals indicated in the requisition.
All documents shall be in the language stated in the requisition.
3.6 Spare Parts' Recommendation
Within 8 weeks after placement of order vendor shall submit his spare parts' recommendation based on one year of continuous operation.
3.7 Erection
Tools necessary to erect the switchgear and bus duct at site shall be furnished by vendor.
Vendor shall submit with the switchgear one set of erection, maintenance and operating instructions.
4. Construction
4.1 Structure
4.1.1 The switchgear shall be designed throughout to ensure safety during operation, inspection, maintenance, connection of cables, relocation of outgoing circuits and maintenance with the busbar system energized and without taking any special precautions.
4.1.2 Equipment shall consist of vertical sections combined so as to form a complete unit. Each vertical section will be completely metal-enclosed.
4.1.3 A construction for which back access is required will be acceptable in case the back access is only necessary to approach buses and cable connections, provided that connection of cables can be achieved when the busbar system is energized and there is no possibility to touch life parts.
4.1.4 Switchgear shall be free-standing on the floor and no external bracing shall be required. Connection to structural steel in floor shall be by bolts. However, tack-welding to steel will be permitted provided that damaged painting will be repainted in the same color. Switchgear shall be provided with removable lifting eyes for easy transport. When a lifting eye is removed from the switchgear, no opening may be left in the enclosure.
4.1.5 Switchgear shall be extendible at both ends by the addition of vertical sections of similar construction.
4.1.6 The panels which shall be executed for bus duct connection shall be supplied complete with sheet metal bus duct hood and reinforcement to carry bus duct weight.
4.1.7 All connections in the bus duct hood shall be installed in such a way that all bolted connections can be checked ( after installation ) with normal tools.
4.1.8 Facilities for power take-off shall be provided at all locations needed by rearrangement of units.
The design shall provide for maximum utilization of switchgear space.
4.2 Enclosures
4.2.1 Equipment shall be designed for indoor or outdoor use as specified in the requisition.
If outdoor service has been specified a rain canopy will form part of the supply.
4.2.2 The front of the panel shall be covered by sheet steel doors corresponding to the number and size of the unit.
4.2.3 Except for openings for wires and ventilation, equipment shall be completely metal-enclosed and compartmented without using the floor as part of the enclosure, unless otherwise stated in the requisition.
Breaker compartment, contactor units, bus spaces, and wiring spaces shall be separated from each other by metal or fire resistant insulating material, walls or barriers. It shall be possible to connect all load side wiring, without special safety precautions, while the bus is energized. Live parts of the main incoming breaker (s) or switch must be absolutely impossible to touch when the breaker(s) or switch(es) are in the ' off ' position. This requirement applies also to main incoming bus and/or cable connections and/or feeder terminals.
Enclosure shall meet the requirements of IEC Publication 144 as stated in the requisition. Opening of busbar compartment and incoming feeder compartments shall only be possible with tools.
Special attention shall be paid to the bus coupler panel compartmenting. The two different bus sections shall be completely separated by means of removable sheets of insulating material.
Copper bars in bus coupler panel shall be insulated.
4.2.4 The switchgear shall be designed to operate satisfactorily at a maximum ambient temperature as stated in the requisition. Ventilation openings, if required, shall be drip-proof and protected against ingress of foreign objects with a diameter of 1 mm and above, unless otherwise specified in the requisition.
Pcalc 4 750 Calorie
Ventilation shall never be dependent on openings in substation floor.
4.2.5 All units shall be accessible from the front by means of hinged doors. Switches, ampere and volt meters and/or signal lights shall preferably be placed on the fixed part, however, installation on the hinged doors is permitted provided that all electrical contacts and terminals carrying a voltage higher than 42 V against earth shall be insulated to prevent accidental contact.
4.2.6 External surface shall be painted as specified in the requisition. Damages shall be repainted with the same type of paint.
4.2.7 Durable and removable nameplates shall be screwed to the door of each unit, plus one for the general designation.
In case terminals for outgoing cables are placed in separately enclosed compartments, nameplates shall also be installed near the terminals.
Languages on nameplates shall be as stated in the requisition. Nameplates shall be white with black engraving.
4.2.8 All doors, covers, etc. shall be provided with soft rubber or PVC rims, to prevent ingress of dust.
4.3 Busbar System
4.3.1 Three-phase power with neutral shall be carried by rigid bus from the incoming main circuit breaker, switch or the incoming cable terminals to the various units.
4.3.2 Main bus shall be rated as shown on the drawings and indicated in the requisition.
4.3.3 The maximum permitted temperature rise of the busbars in 35°C under full-load conditions with an ambient temperature of 35°C.
4.3.4 All buses shall be dynamically braced and thermally sized for the short circuits shown on the drawings and in the requisition.
4.3.5 All connection bolts and nuts shall be accessible so that they can be checked with normal tools.
All bolts, nuts and washers shall be sized for the busbar dimensions indicated in DIN 43673.
4.3.6 Bus colors shall be as specified in the requisition.
The buses shall be marked with painted dots. Application of self-adhesive tape is not acceptable.
4.3.7 Neutral buses shall be rated for at least half the capacity of each phase bus, insulated from the structure as the phase buses and colored as indicated in the requisition.
4.3.8 Removable neutral links shall be provided for all bus tie breakers, incoming breaker(s) or switches as indicated on the drawing(s).
4.3.9 A one piece bare copper ground bus shall extend throughout the length of the equipment, with copper branches going to all possible units.
Terminals shall be provided at both ends of the switchgear for connection of maximum 70 mm2 grounding cable.
The copper ground bus shall be mounted directly on the equipment structure, thus grounding the structure. The minimum size of the ground bus shall be 25x5 mm. The ground bus shall not be used for neutral wire connections. Near the connections and/or terminals for the outgoing cables branch, ground buses shall be installed with at least 1 earth screw for each outgoing or incoming cable.
The ground bus shall be colored as indicated in the requisition. Connections shall be made with cadmium-plated screws, nuts and washers through the ground bus. It will not be allowed to provide ground bus with threaded holes.
4.3.10 Busbar joints shall be made by galvanized or cadmium-plated high tensile strength steel bolts, nuts and washers and be secured against loosening.
Minimum mutual distance between live parts shall be 20 mm.
Minimum distance between live parts and neutral to ground shall be 25 mm.
Minimum distance between live parts and neutral shall be 20 mm, unless otherwise specified in the requisition.
4.3.11 Busbars shall be made of hard-drawn high conductivity electrolytic copper.
4.3.12 The busbar supports and end barriers shall be made of high quality nonhygroscopic nonflammable insulating material.
4.3.13 Connection from the vertical branch bars to the main fuses of outgoing circuits shall be as short as possible. These main fuses shall be mounted directly on the bars; if this cannot be done the connections from the bus to the main fuses shall be screened with nonflammable insulating material.
4.3.14 Vendor's scope of supply and installation starts at the flange connection of the transformer to the bus duct, including the connection of the bus duct to the transformers unless otherwise specified.
4.3.15 If bus ducts are included in the requisition, mounting of bus ducts at site shall be carried out by switchgear supplier or his subcontractor, unless specified otherwise.
This includes all provisions, materials and services mentioned in the separate bus duct specification.
4.4 Foundation and Floor Construction
Vendor shall supply and supervise erection of all necessary floor supporting steel and/or other structural provisions to carry the switchgear.
Company will provide the following:
Holes and pockets in concretefloor as indicated on vendor's drawings.
Pouring concrete around vendor's structural steel ( if required ) after alignment by vendor.
All other work including supply of all necessary material such as, but not limited to:
Supports, beams, anchor bolts, etc.
will form part of vendor's scope of supply and erection
Later changes to floor or leveling the switchgear by means of chimes will be at vendor's expense.
Structural steel that shall be poured in the floor must be supplied approximately two months after switchgear has been ordered.
Final date to be checked with Badger's Construction Superintendent or his representative. Structural steel and/or other provisions that shall be made in the floor must be suitable for 2 additional cubicles on each side for later extension.
4.5 Interlocking
Cubicle doors shall be interlocked against opening when breaker, contactor or switch is in the ' in ' position.
However, it shall be possible for an electrician to by-pass this interlocking in a simple way for inspection purposes. By-pass interlocking applies only to contactor units, and not to a fuse switch unit.
4.5.1 An interlock shall prevent closing contactor or switch as soon as door is opened.
4.5.2 A mechanical interlock shall prevent to ' draw in ' or to ' draw out ' an incoming feeder or tie breaker when breaker is in the closed position.
4.6 Wireway, Cable Tray and Wiring
4.6.1 Cable tray and cable clamps shall be provided to mount all incoming and outgoing cables within the switchboard.
4.6.2 Wireways have to be provided for wiring between units in the same or different vertical sections without going outside the equipment.
4.6.3 Control wires shall be 1.5 mm2 - 750 V within the switchgear, provided that control fuse rating does not exceed 10 A. If 16 A control fuses are installed control wiring shall be at least 2.5 mm2 . CT wires shall be at least 4 mm2 - 750 V within switchgear.
All wiring to be PVC-insulated. Wires to be stranded. The stranded wires shall be provided with cable lugs or cable pins of the ' crimpit ' type. Cable lugs shall be of the insulated type.
4.6.4 Each wire shall be terminated in a separate terminal. Fixing of two or more wires under one screw or one screw or one terminal is not allowed.
4.6.5 The wires shall not be joined or tied between terminal point.
4.6.6 All doors provided with electrical equipment shall be earthed by means of a flexible connection to the stationary part of the switchgear.
4.6.7 All interconnecting wiring in the switchgear shall be connected by vendor.
The wiring from the main bus bar system to the knife-type fuses shall have a 750 V insulation and will not touch steel structure or other wiring or equipment.
4.7 External Cable Connections
4.7.1 It shall be possible to bring incoming and outgoing cables to the equipment from below through a hole in the concrete substation floor, unless otherwise specified. Straps shall be installed to fix the cables. Cable glands for plastic or rubber covered cables will not be required for switchgear which will be located indoors and cables are coming from below. Paper-insulated cables shall be provided with potheads. Potheads may not protrude through the substation floor. The potheads will form belong to vendor's supply.
4.7.2 Provisions shall be made for terminating each incoming, outgoing cable and grounding wire with a separate screwed or bolted cable terminator supplied with the control center.
4.7.3 Cable boxes shall be of the split type.
4.7.4 An earthing terminal shall be provided inside the cable box for earthing the lead sheath of the cable.
4.7.5 It shall be possible to measure the motor current without disconnecting the wiring.
4.7.6 All terminals and connection screws shall be properly sized for the cable core and ground wire cross-section used. All terminal blocks shall be easily accessible from the front of the switchgear.
4.8 'Spare' and 'Space' Compartments
Compartments indicated 'spare' shall be completely equipped with all necessary components for the type and size of circuit specified.
Compartments indicated as 'space' shall be empty, however, prepared as required under paragraph 4.7.
4.9 Rating
Operational current rating of all equipment and busbars shall be in accordance with IEC.
4.10 Breakers
4.10.1 Electrically operated breakers shall be controlled by power from the busbar system, unless otherwise stated in the requisition. Provisions shall be made for emergency manual closing and tripping at front of switchgear.
4.10.2 Breakers shall be anti-pump, and free to trip if closed on a short circuit, whether manually or electrically, even when the operating handle or switch is held in the 'close' position. The anti-pump function shall be maintained despite loss of bus voltage during the fault.
Breakers shall trip instantaneously and without selective time delay when closed against a short circuit. Paragraph 4.10.2 applies only when incoming breakers are provided with protection relays.
4.10.3 Breaks shall indicate mechanically the open on closed position through the door.
4.10.4 All breakers shall be provided with one NO and one NC auxiliary contact for interlocking, completely wired and terminated at terminals.
4.10.5 All breakers rated 350 A and above shall be of the 'draw-out' type.
Following requirements shall apply for withdrawable type breakers:
Breakers shall be made before the breaker can be closed.
If a breaker is 'closed' it may not be possible to either move it from the plugged-in position to the test position or in reverse direction.
It may not be possible to close or trip a breaker, either mechanically or electrically in any position between the test and the plugged-in position.
Breakers shall, if lifted from the test position for inspection etc., have their operating energy discharged before final lift-off is possible or it is removed from the cubicle.
Breakers of the same size shall be interchangeable. To preserve interchangeability, provisions for special control shall not be mounted directly onto breaker.
When a separate lifting truck is required to handle circuit breakers to and from the cubicle, the truck shall form part of the supply.
4.10.6 Breakers may not be mounted directly under the busbars or copper bars.
A pertinax plate shall be fitted between the copper bar system and the arcing devices of the breaker. Special care should be taken that ionized air can cool down.
4.10.7 Closing or breaking time of the breaker contacts shall not depend on the speed of operating the handle.
4.11 Fuses
4.11.1 Fuses used in combination with contactors shall be of 'high rupturing capacity' type and rated to completely protect the thermal relays and contactors against short circuits. Fuses shall be sized to allow direct on-line start of each motor ( time lag fuses or other special execution ).
4.11.2 Current limiting fuses used in a busbar system to decrease the short-circuit capacity of the system shall not be sized larger than 200 A.
4.11.3 Screw type fuses are only allowed under the following conditions:
With E27 threading
Not exceeding 25 A rating
Used after fuses as meant in 4.10.2 (does not apply for fuses for metering smaller than 6 A).
4.11.4 Power and control fuses shall be readily accessible for replacement. It shall not be necessary to remove any piece of equipment or to disconnect wiring or cables when replacing fuses.
4.11.5 A separation between knife type fuses will be required to avoid accidental short circuits. The separation shall be done with pertinax plates. The pertinax plates are not both sides of the fuses and these plates must be 2 cm longer and higher as any bare live part of the fuse, fuse holder, copper bar or wiring lugs.
4.11.6 All fuses shall be provided with means to show that they are blown.
4.12 Contactors
4.12.1 Contactor coils shall be suitable for continuous energization ( uninterrupted duty ), with a supply voltage, which can be 10% higher and lower than the contactor coil nominal voltage.
4.12.2 Control voltage connected to phase and neutral unless otherwise stated in the requisition. If main fuse rating is 10 A or less, control fuses are not required. Control voltage is taken behind one main fuse (1st phase ) and neutral. Fuses in neutral will not be required.
4.12.3 Contactors shall be suitable to withstand and to switch 'off' locked rotor current of motors for 5 seconds. Locked rotor currents of motors to be maximum 600% for nonexplosion protected motors and fully explosion protected motors and 800% for motors with rotor temperature restriction, unless stated otherwise on the one-line diagram.
4.12.4 Rated operational current rating of contactors shall be at least 1.25 x nominal current of motor, with the smallest contactor size of 20 A ( operational current ) under AC3 conditions of IEC 158-1.
4.12.5 Contactors shall be provided with 3-phase thermal overload relays with hand reset and protection against single phasing.
Application of current transformers for thermal overload protection for larger motors will be allowed if economically justified.
Reset shall be possible from the front of the switchgear without opening the doors.
Closed position shall be indicated by red colored signal lamp assemblies. Signal lamps shall consist of a metal body with a colored glass lens cap.
Type of the luminescent lamp shall be shock-resistant and preferably on a lower voltage.
If requisition shows that Exe electric motors are involved, vendor shall supply thermal relays as required by VDE 0170/0171 part 6 paragraph 3.7.4.
4.12.6 All contactors shall be provided with auxiliary contacts and terminals as indicated in wiring diagram on sheet 30 of this specification.
4.12.7 It must be possible to operate contactors with a control cable of 250 m length ( cable 2.5 mm2 ).
If it is impossible to close contactor due to high inrush current of contactor-coil, vendor shall supply auxiliary relays for this purpose ( see also wiring diagram ).
4.12.8 'Start-stop' rotary switch stations for all motors shall be arranged so that momentary operation of the stop switch stops the motor. Relay will not be acceptable to hold the switch in the stop position for the time of undervoltage.
4.13 Terminals
4.13.1 Terminals shall be grouped with regard to their different voltages.
There shall be a minimum of 5 cm space or separation of insulating material between terminal blocks carrying different voltages.
Separator shall extend one cm above the terminal.
4.13.2 Terminals for outgoing current transformer wiring shall be provided with short-circuit devices.
If open, the link shall point downwards.
5. Tests
5.1 Tests to Be Carried Out in the Factory
( See also Specification for the Inspection of Low Tension Switchgears )
5.1.1 Checking of all control wiring.
5.1.2 Operating test of all protective relays.
5.1.3 Mechanical test ( door locks etc. ).
5.1.4 Appearance test ( painting, near surface, nameplates, etc.).
5.1.5 Megger test. Resistance between busbars and between busbars and ground must be at least 10 megohm.
5.1.6 High potential test 2500 V - 1 minute, unless otherwise specified.
5.1.7 Try to make a short while pulling fuses.
5.1.8 Check accessibility of busbar connection bolts and nuts with normal tools.
5.1.9 Testing of thermal relays with time clock and current injection set to check if relays stay within their curves.
5.2 Test and Proof Operation to Be Carried Out at Site
5.2.1 Megger testing resistance between busbars and between busbars and earth must be at least 10 megohm.
5.2.2 High potential test, 2000 V, 1 minute.
5.2.3 Check of all bolted bus, busduct and transformer connections.
5.2.4 Check of all terminals.
5.2.5 Proof operation and test after announcement 'power available'.
5.2.6 Visual inspection for freedom of dust and waste material.
5.3 General Test Procedure
5.3.1 All test equipment necessary for tests described under 5.1 ( and 5.2 if specified ) shall be furnished by vendor.
5.3.2 All tests shall be witnessed by a representative of Company.
6. Metering Equipment and Current Transformers
6.1 Meters
Meter shall be flush-mounted in the front of the switchboard. Their minimum size shall be 96 mm2.
Remote meters shall not be connected to current transformers provided for to protective relaying.
6.2 Current Transformers
6.2.1 Current transformers shall have accuracy class 1 for metering and accuracy class for protection.
6.2.2 The current transformers shall maintain sufficient accuracy under all overload and short-circuit conditions, to ensure the proper relay operations for protection and selectivity.
6.2.3 Current transformers shall be capable of withstanding the peak momentary short circuit, and the symmetrical short-circuit current for 1 second, unless otherwise specified in the requisition.
7. Unit Type Switchboard
If vendor's standard unit type switchboards can be adapted to meet the requirements of this specification this type will also be acceptable.
8. Spare Parts
The following spare parts shall be supplied together with the switchgear:
8.1 - 12 fuses of every type used in the switchgear, up to 63 A.
- 6 fuses of every type used in the switchgear, 63 A and above.
8.2 - 10 signal lamps of the same type used in the switchgear.
Table of Contents
1. Tankage Grouping
2. Classification of Crude Oil and Its Derivatives
3. Tankage Layout
4. Pump Areas
5. Fire Protection
6. Road and Rail Loading Facilities
1. Tankage Grouping
Tankage area will be subdivided into various groups determined by the contents of the tanks and the relative shape and area of the plot available, access and fire fighting must also be considered. See below table API tank size for layout purposes.
2. Classification of Crude Oil and Its Derivatives
Crude oil and its derivatives are potentially hazardous materials. The degree of the hazard is determined essentially by volatility and flash point.
The Institute of Petroleum has specified the following classes:
| Class 0 | Liquified petroleum gases (LPG) | |
| Class I | Liquids which have flash points below 21 oC | |
| Class II | (1) | Liquids which have flash points from 21 oC upto and including 55 oC handled, below flash point |
| Class II | (2) | Liquids which have flash points from 21 oC upto and including 55 oC handled, at or above flash point |
| Class III | (1) | Liquids which have flash points above 55 oC upto and including 100 oC handled, below flash point |
| Class III | (2) | Liquids which have flash points above 55 oC upto and including 100 oC handled, above flash point |
| Unclassified. | Liquids with flash points above 100 oC |
For further information see IP refinery safety code part 3.
3. Tankage Layout
3.1 General
The layout of tanks, as distinct from their spacing, should always take into consideration the accessibility needed for fire-fighting and the potential value of a storage tank farm in providing a buffer area between process plant and public roads, houses, etc. , for environmental reasons.
The location of tankage relative to process units must be such as to ensure maximum safety from possible incidents.
Primarily requirements for the layout of refinery tanks farms are summarised as follows.
- Inter tank spacings and separation distances between tank and boundary line and tank and other facilities are of fundamental importance. (See 3.2) .
- Suitable roadways should be provided for approach to tank sites by mobile fire fighting equipment and personnel.
- The fire water system should be laid out to provide adequate fire protection to all parts of the storage area and the transfer facilities.
- Bunding and draining of the area surrounding the tanks should be such that a spillage from any tank can be controlled to minimise subsequent damage to the tank and its contents. They should also minimise the possibility of other tanks being involved.
- Tank farms should preferably not be located at higher levels than process units in the same catchment area.
- Storage tanks holding flammable liquids should be installed in such a way that any spill will not flow towards a process area or any other source of ignition.
3.2. Spacing of Tanks for LPG Stocks of Class 0
| Factor | Recommendations for LPGStored in Pressure Tanks |
| 1. Between LPG pressure storage tanks | One quarter of the sum of the diameters of the two adjacent tanks. |
| 2. To Class I, II, or III product tanks. | 15 M from the top of the surrounding Class I, II or III product tanks. |
| 3. To low pressure refrigerated LPG tanks. | One diameter of the largest low pressure refrigerated storage tanks but not less than 30 M. |
| 4. To building containing flammable material e.g. filling shed, storage building. | 15 M |
| 5. To boundary or any fixed source of ignition. | Related to water capacity of tank as follows : |
| Capacity Up to 135 cu.M Over 135 to 565 cu.M Over 565 cu.M | Distance 15 M 24 M 30 M |
The distance given in the above table are minimum recommendations for aboveground tanks and refer to the horizontal distance in plan between the nearest point on the storage tank and a specified feature, e.g. an adjacent storage tank, building, boundary. The distances are for both spherical and cylindrical tanks.
3.3 Bunding and Grouping of LPG Tanks
The provision of bunds around LPG pressure storage tanks is not normally justified.
Separation kerbs, low to avoid gas traps, maximum 600 mm high, may be located to prevent spillage reaching important areas, e.g. pump manifold area, pipe track.
Ground under tanks should be graded to levels which ensure that any spillage has a preferential flow away from the tank.
Pits and depressions, other than those which have been provided as catchment areas, should be avoided to prevent the forming of gas pockets.
Pressure storage tanks for LPG should not be located within the bunded enclosures of Class I, II or III product tankage or of low pressure refrigerated LPG tankage.
The layout and grouping of tanks, as distinct from spacing, should receive careful consideration with the view of accessibility for fire fighting and the avoidance of spillage from one tank flowing towards the other tank or towards a nearby important area.
3.4 Spacing of Tanks for Low Pressure Refrigerated LPG Storage Class 0
| Factor | Recommendations for Low Pressure Refrigerated LPG Storage |
| 1. Between refrigerated LPG storage tanks | One half of the sum of the diameters of the two adjacent tanks. |
| 2. To Class I, II, or III product tanks. | One diameter of the largest refrigerated storage tank but not less than 30 M. |
| 3. To pressure storage tanks. | One diameter of the largest refrigerated storage tank but not less than 30 M. |
| 4. To process units, office building, work-shop, laboratory, warehouse, boundary, or any fixed source of ignition. | 45 M |
The distance given in the above table are minimum recommendations and refer to the horizontal distance in plan between the nearest point on the storage tank and a specified feature, e.g. an adjacent storage tank, building, boundary.
3.5. Bund or Impounded Basin for Refrigerated LPG Storage
A bund should be provided around all low pressure tanks containing refrigerated LPG. The tank should be completely surrounded by the bund, unless the topography of the area is such, either naturally or by construction, that spills can be directed quickly and safely, by gravity drainage and diversion walls if required, to a depression or impounding basin located within the boundary of the plant.
Bunds should be designed to be of sufficient strength to withstand the pressure to which they would be subjected if the volume within the bunded enclosure were filled with water. The area within the bund, depression, or impounding basis should be isolated from any outside drainage system by a valve, normally closed unless the area is being drained of water under controlled conditions.
Where only one tank is within the bund, the capacity of the bunded enclosure, including the capacity of any depression or impounding basis, should be 75 per cent of the tank capacity. Where more than one tank is within the main enclosure, intermediate bunds should be provided, so as to give an enclosure around each tank of 50 per cent of the capacity of that tank, and the minimum effective capacity of the main enclosure, including any depression or impounding basin, should be 100 per cent of the capacity of the largest tank, after allowing for the volume of the enclosure occupied by the remaining tanks. It is desirable for the required capacity to be provided with bunds not exceeding an average height of 6 foot as measured from the outside ground level.
The area within the bund should be graded to levels which ensure that any spillage has a preferential flow away from the tank.
No tankage other than low pressure tankage for refrigerated LPG should be within the bund. The layout and grouping of tanks, as distinct from spacing, should receive careful consideration with the view of accessibility for fire fighting.
3.6 Piping Installation and Flexibility
Liquid and vapour pipelines should have adequate flexibility to accommodate any settlement of tanks or other equipment, thermal expansion or other stresses that may occur in the pipe work system.
Precaution must be taken to prevent drain or sample valves freezing in the open position. The flow diagram will indicate the type of double valving to be installed, with a minimum distance between the valves of 1 meter. Do not allow liquid traps in vent lines.
3.7 Spacing of Tank for Petroleum Stocks of Classes I, II and III (2) .
| Factor | Type of Tank Roof | Recommended Minimum Distance |
| 1. Within a group of small tanks | Fixed or Floating | Determined solely by construction / maintenance operational convenience |
| 2. Between a group of small tanks or other larger tanks. | Fixed or Floating | 10 M minimum, otherwise determined by the size of the larger tanks (see 3 below) |
| 3. Between adjacent individual tanks (other than small tanks). | (a)Fixed | Half the diameter of the larger tank, but not than 10 M and need not be more than 15 M. |
| (b)Fixed | 0.3 times the diameter of the larger tank, but not less than 10 M and need not be more than 15 M. (In the case of crude oil tankage this 15 M option does not apply) | |
| 4. Between a tank and the top of the inside of the wall of its compound | Fixed or Floating | Distance equal to not less than half the height of the tank. (Access around the tank at compound grade level must be maintained) |
| 5. Between any tank in a group of tanks and the inside top of the adjacent compound wall. | Fixed or Floating | |
| 6. Between a tank and a public boundary fence. | Fixed or Floating | Not less than 30 M |
| 7. Between the top of the inside of the wall of a tank compound and a public boundary fence or to any fixed ignition source. | Not less than 15 M | |
| 8. Between a tank and the battery limit of a process plant. | Fixed or Floating | Not less than 30 M |
| 9. Between the top of the inside wall of a tank compound and the battery limit of a process plant | - | Not less than 15 M |
The table above gives a guidance on the minimum tank spacing for Class I, II and III (2) storage facilities, the following points should be noted.
- Tanks of diameter up to 10 M are classed as small tanks
- Small tanks may be sited together in groups, no group having an aggregate capacity of more than 8000 m3. Such a group may be regarded as one tank.
- Where future changes of service of a storage tank are anticipated the layout and spacing should be designed for the most stringent case.
- For reasons of fire fighting access there should be no more than two rows of tanks between adjacent access roads.
- Fixed roof with internal floating covers should be treated for spacing purposes as fixed roof tanks.
- Where fixed roof and floating roof tanks are adjacent, spacing should be on the basis of the tank(s) with the most stringent conditions.
- Where tanks are erected on compressible soils, the distance between adjacent tanks should be sufficient to avoid excessive distortion. This can be caused by additional settlements of the ground where the stressed soil zone of one tank overlaps that of the adjacent tank.
- For Class III (1) and unclassified petroleum stocks, spacing of tanks is governed only by constructional and operational convenience. However, the spacing of Class III (1) tankage from Class I, II or III (2) tankage is governed by the requirements for the latter.
- For typical tank installation, illustrating how the spacing guides are interpreted see below figures.
For details of a typical vertical tank foundation see below figures.
3.8 Tank Farm Piping and Layout
Pipelines connected to tanks should be designed so that stresses imposed are within the tank design limits. The settlement of the tank and the outward movement of the shell under the full hydrostatic pressure should be taken into account. The first pipe support from the tank should be located at a sufficient distance to prevent damage both to the line and to tank connections. Consideration may be given to installing spring supports near to tank connection for large bore pipework.
As large diameter tanks have a tendency to settle on their foundations, provision must be made in the suction and filling piping to take care of tank settlement. This may require the use of expansion joints, victaulic couplings, or a lap joint flange installed as shown in see below figure.
The following note must be added to all piping drawings containing storage tanks:
'All piping must be disconnected from tank during hydrostatic test of storage tank'
The number of pipelines in tank compounds should be kept to a minimum. They should be routed in the shortest practicable way to the main pipe tracks located outside the tank compounds, with adequate allowance for expansion.
Flexibility in piping systems may be provided through the use of bends, loops or offsets. Where space is a problem suitable expansion joints of the bellows type may be considered for installation in accordance with manufacturer's design specifications and guides. These expansion joints should be used only in services where the fluid properties are such that plugging of the bellows cannot occur. They should be anchored and guided, should not be subjected to torsional loads, and should be capable of ready inspection.
Tank farm piping should preferably be run above ground on concrete or steel supports. Ground beneath piping should be so graded as to prevent the accumulation of surface water or product leakage. Manifolds should be located outside the tank bunds.
Piping should pass over earth bund walls, however, if this is impossible, a suitable pipe sleeve will be provided to allow for expansion and possible movement of the lines. The annular space should be properly sealed. Likewise lines passing through concrete bund walls will be provided with pipe sleeves.
Pedestrian walkways should be provided to give operational access over ground level pipelines.
Pipelines should be protected against uneven ground settlement where they pass under roadways, railways or other points subject to moving loads.
Buried pipelines should be protected externally by corrosion preventing materials, or by cathodic means.
Routes of buried pipelines should be adequately marked above ground and recorded.
Pipe racks carried across paths or roads should have adequate clearance from grade. Adequate access stairways or ladders and operating platforms should be provided to facilitate operation and maintenance at tanks. Tanks may be interconnected at roof level by bridge platforming.
All nozzles, including drains on a tank shell, should have block valves adjacent to the tank shell or as close as practicable.
3.9 Tank Bund Compound Capacities
Above ground tanks for Class I, II (1), II (2) and III (2) petroleum liquids should be completely surrounded by a wall or walls. Alternatively, it is acceptable to arrange that spillage or a major leak from any tank are directed quickly and safely by gravity to a depression or impounding basis at a convenient location.
The distance between the edge of the impounding basin and the nearest tank or the inside top of the nearest bund wall should be a minimum of 30 M. The distance between the edge of the basin and road fence battery limit of a process plant should not be less than 15 M.
The height of the bund wall as measured from outside ground level should be sufficient to afford protection for personnel when engaged in fire fighting and the wall should be located so that a reasonably close approach can be made to a tank fire to allow use of mobile fire fighting equipment. Access roads over bund walls into very large compounds are helpful in certain fire situations.
Separate walls around each tank are not necessary, but the total capacity of the tanks in one bunded area should be restricted to the following maximum figures:
| Single tanks | No restriction |
| Groups of floating roof tanks | 120,000 m3 |
| Groups of fixed roof tanks | 60,000 m3 |
| Crude tanks | Not more than two tanks of greater individual capacity than 60,000 m3 |
The figures for b. and c. may be exceeded for groups of not more than three tanks, where there can be no risk of pollution or hazard to the public.
Pcalc 4 750 Motorcycle
Intermediate walls of lesser height than the main bund walls may be provided to divide tankage into groups of a convenient size so as to contain small spillages and act as fire breaks.
Buried, semiburied or mounded tanks need not be enclosed by a bund wall except when they are located in ground higher than the surrounding terrain. However, consideration should be given to the provision of small bund walls around associated tank valves.
The net capacity of the tank compound should generally be equivalent to the capacity of the largest tank in the compound. However, a reduction of this capacity of 75% will provide reasonable protection against spillage and may be adopted where conditions are suitable (e.g. where there can be no risk of pollution or hazard to the public). The net capacity of a tank compound should be calculated by deducting from the total capacity a. the volume of all tanks, other than the largest, below the level of the top the compound wall and b. the volume of all intermediate walls.
A low wall which need not be more than 0.5 m high, should be constructed for Class III (1) and unclassified petroleum product tankage where conditions are such than any spillage or leakage could escape from the installation and cause damage to third party property drainage systems, rivers or waterways.
Where there is a possibility that tanks storing these products may be in the future required for Class I, II (1) or III (2), then the compound walls should be suitable for this potential situation.
4. Pump Areas
Pumps will be located outside bund areas. The vessels practice is to group the pumps into bays. Keep the suction lines as short as practical. The discharge piping will run on low level tracks to the process or loading areas. These tracks will usually pass under roads in culverts, but may pass over on a pipe bridge. Long pipe runs may require expansion loops to provide flexibility. Consult with stress section.
5. Fire Protection
For storage areas the major fire fighting effort will be provided by mobile equipment laying down large blankets of foam and/or applying large volumes of water for cooling purposes.
It is essential to provide a good system of all weather roads to facilitate the transfer of fire protection materials and equipment to the scene of the fire. These roads must be of adequate width and, wherever possible, with no deadends.
It is important in the siting of tanks, bund walls and access roads that the tanks can be protected by cooling water or foam appliances situated outside the compound walls. Account must be taken of the height of the tank and the possible need to cool the roof or project foam on to a tank.
Dry risers for foam may be provided to the top of storage tanks with their connections adjacent to access roads, fixed monitors may also be employed. The flow diagram will define the system to be employed.
6. Road and Rail Loading Facilities
Road and rail loading facilities are usually associated with storage area. The safe location of these in relation to storage tanks is laid down in section 3.7.
The road or railcar will be filled from a loading island, the supply lines will be either routed underground, or on an overhead pipe bridge. Check for clearances.
Below figures show such installations.
It has become common practice to provide a vapour collection system for the safe removal of vapours during the loading process. This system would employ unloading arms which are connected to a collection system and piped to a vent stack at a safe location.
When laying out a loading area consideration must be given to the number of vehicles or rail cars per hour to be loaded. A suitable movement pattern must be established for incoming and outgoing vehicles or railcars. Weigh bridges will be required, the system of moving rail cars must be defined, building housing, operation offices and facilities for drives etc. , must be provided.
Figures:
API TANK SIZE - FOR LAYOUT PURPOSE
Based on API650
| Capacity Approximately | Diameter | Height | |
| US Barrels | CU Meters | Meters | Meters |
75 | 4.9 | ||
150 | 4.9 | ||
225 | 7.3 | ||
300 | 7.3 | ||
450 | 7.3 | ||
600 | 9.3 | ||
750 | 12.2 | ||
900 | 14.6 | ||
1050 | 9.9 | ||
1350 | 12.2 | ||
1500 | 12.2 | ||
1800 | 14.6 | ||
2250 | 14.6 | ||
3000 | 12.2 | ||
4500 | 12.2 | ||
6000 | 12.2 | ||
7500 | 14.6 | ||
12000 | 12.2 | ||
15000 | 12.2 | ||
18000 | 14.6 | ||
21000 | 12.2 | ||
27000 | 12.2 | ||
30000 | 14.6 | ||
45000 | 17.0 | ||
60000 | 17.0 | ||
90000 | 14.6 | ||
100000 | 14.6 |
Pcalc 4 750 Atv
Figure 1.
TANKS A, B, C ARE FIXED OR FLOATING ROOF SMALL TANKS (LESS THAN 10 m. DIAMETER) WITH A TOTAL CAPACITY OF LESS THAN 8000 m3; NO INTER-TANK SPACING REQUIREMENTS OTHER THAN FOR CONSTRUCTION / OPERATION / MAINTENANCE CONVENIENCE. TANKS D1 & D2 ARE TANKS WITH DIAMETERS GREATER THAN 10 m., & WITH DIAMETER OF D2 GREATER THAN D1.
Inter-tank spacings between small and larger tanks.
Tank and compund wall distances from typical features.
Figure 2.
FLOATING ROOF TANKS OF DIAMETER D1 D2 D3 GREATER THAN 10 m. WITHIN THE SAME COMPUND. D1 GREATER THAN D2 & D2 GREATER THAN D3.
Figure 3.
Inter-tank spacing for floating roof tanks (greater than 10 m diameter).
FIXED & FLOATING ROOF TANKS WITHIN THE SAME COMPOUND. D1 GREATER THAN D2, D2 EQUAL TO D3.
Figure 4.
Pcalc 4 750 Mg
Lap joint Flange Detail for Tank Settlement
Figure 5.
Pcalc 4 750 Kawasaki
Foundation for vertical tank
Based on BS2654
Figure 6.
