CONTENTS Section Page SCOPE... 4 REFERENCES... 4 DESIGN PRACTICES... 4 INTERNATIONAL PRACTICES... 4 OTHER REFERENCES... 4 DEFINITIONS... 4 INTRODUCTION... 4 GENERAL... 4 PRODUCT SERVICE... 5 HOSES... 5 Rubber Hose... 5 Composite Hose... 5 Metallic Hose... 6
HOSE SYSTEM SELECTION... 6
HOSE VS. LOADING ARM... 6
HANDLING EQUIPMENT... 8
Mast and Boom... 8
Hydraulic Telescoping Crane... 8
Gantry Rig... 8
Half Metal – Half Hose... 8
HOSE SELECTION... 8 GENERAL... 8 SERVICE REQUIREMENTS... 9 Operating Parameters... 9 Product... 10 Aromatics / MTBE... 10 Electrical Continuity... 10 Vacuum... 11 Bend Radius... 11 PRESSURE RATING... 11
Rated Working Pressure... 11
Burst Test Pressure... 12
FLUID FLOW... 12
Flow Rate... 12
Pressure Losses... 12
Section Page
LENGTH... 13
Operating Envelope... 13
Crane / Derrick Reach... 15
LIFE EXPECTANCY... 15
Nominal Retirement Age... 16
Maximum Retirement Age... 16
END-FITTINGS... 17 HOSE END-FITTINGS... 17 Built-in Nipples... 17 Swaged Couplings... 17 FLANGES... 17 Bolting... 17 Gaskets... 17 Couplers... 18 ELECTRICAL INSULATION... 18 PROTOTYPE TESTING... 18 APPROVAL TESTS... 18 CERTIFICATION... 18 PRODUCTION TESTING... 18 APPROVAL TESTS... 19 TEST CERTIFICATES... 19 PURCHASING... 19 MARKING... 19
PREPARATION FOR SHIPMENT... 19
STORAGE... 19
HOSE HANDLING... 21
ROUTINE INSPECTION AND TESTING... 21
APPENDIX A – TERMS AND DEFINITIONS... 34
DEFINITIONS WITH RESPECT TO DOCK HOSES... 34
DEFINITIONS ON PRESSURE RATINGS... 38
APPENDIX B – LIQUEFIED HYDROCARBON GAS (LHG) MARINE CARGO TRANSFER FIRE / EXPLOSION RISK ASSESSMENTS... 41
LIQUEFIED HYDROCARBON GAS (LHG) CARGO TRANSFER FIRE / EXPLOSION RISK ASSESSMENT PROCEDURE ... 43
LIQUEFIED HYDROCARBON GAS (LHG) CARGO TRANSFER FIRE / EXPLOSION RISK ASSESSMENT SCENARIOS / CASES... 44
Section Page TABLES
Table 1 Cargo Transfer Equipment Alternatives... 7
Table 2 Hose Selection Parameters... 9
Table 3 Vessel Drift and Surge Allowances... 14
Table 4 Operating Envelope Governing Conditions... 14
Table 5 Data Requirements For Operating Envelope... 14
Table 6 Hose Retirement Criteria... 15
Table 7 Dock Service... 16
Table 8 Tower-Supported Service... 16
Table 9 Data Sheet For Purchasing Hose... 20
FIGURES Figure 1 Rubber Hose Construction... 22
Figure 2 Composite Hose Construction... 22
Figure 3 Mast and Boom Hose Handling System... 23
Figure 4 Gantry Rig Hose Handling System... 24
Figure 5 Half Metal – Half Hose Handling System... 25
Figure 6 Operating Envelope... 26
Figure 7 Operating Envelope Governing Conditions... 27
Figure 8 Example Problem Operating Conditions... 28
Figure 9 Example Problem Operating Envelope... 29
Figure 10 Hose Built-in Nipple (BIN)... 30
Figure 11 Hose Swaged Fitting... 30
Figure 12 Hose Arrangement with Insulating Flange... 31
Figure 13 Insulating Flanges... 31
Figure 14 Hose Handling Examples... 32
Figure 15 Hose Coupler... 33
Figure A-1 Schematic Illustration on Relationship of Pressure Definitions... 40
Figure B-1 LHG Weight in Cargo Transfer Equipment LHG Weight Based on Volume of Contents... 47
Revision Memo 12/99 Original Issue of Design Practice XXXI-G
This practice covers cargo transfer hoses for the loading and discharge of ships and barges at conventional marine pier (dock) and sea islands facilities. Information is provided for definition of the cargo transfer system, and specifically for defining hose type and performance requirements. As selection of hose systems require knowledge on the use of hoses, pertinent information is provided on hose purchasing, storage, use, and testing. Although some information is provided on operational aspects, the document is not intended to cover ongoing inspection and maintenance of hoses and ancillary equipment.
This section of the Design Practice is not intended for Offshore Hoses (floating and submarine), which are covered in Section
XXXI-H. Hoses used for truck or rail car cargo transfer are not covered by this practice. REFERENCES
DESIGN PRACTICES
XXIII Product Loading Systems
XXXI-F Cargo Transfer Equipment – Loading Arms
XXXI-H Cargo Transfer Equipment – Offshore Hoses
XXXI-J Ship-to-Shore Electrical Isolation
XXXI-I Safety Considerations for the Design of Marine Terminals
INTERNATIONAL PRACTICES
IP 3-11-1, Marine Cargo Transfer Hose
IP 3-11-2, Marine Loading Arms
OTHER REFERENCES
1. International Safety Guide for Oil Tankers and Terminals (ISGOTT), International Chamber of Shipping, Oil Companies International Marine Forum, International Association of Ports and Harbors, Fourth Edition, 1996.
2. Rubber Hose Assemblies For Oil Suction And Discharge Services – Specification For The Assemblies, European Standard EN-1765, 1997.
3. Rubber Hose Assemblies For Oil Suction And Discharge Service, Part 2 Recommendations For Storage, Testing And Use, British Standards Institute BS-1435: Part 2, 1990.
4. Rubber Hoses And Hose Assemblies, Part 1: On-Shore Oil Suction And Discharge Specification, International Standard ISO 1823-1, 1997.
5. Rubber Hose for Oil Suction and Discharge Specification, Rubber Manufacturers Association, IP-8, 1996. 6. Purchase Specification and Inspection Guidelines for Marine Cargo Transfer Hose, ER&E Report No. EE.76E.92
7. Dock Hose Technology & Practice Training Video, ER&E Report No. EE.40E.94.
8. Marine Terminal Inspection and Maintenance Guide, ER&E Report No. EE.132E.95, (Technical Manual TMEE 066). 9. Updated Guidelines for Prevention of Electrostatic Ignitions, ER&E Report No. EE.2M.98.
10. Flexible Metallic Hose Assemblies, Part 1 Specification For Corrugated Hose Assemblies, British Standards Institute, BS-6501: Part 1, 1991.
11. LHG Marine Cargo Transfer Fire/Explosion Risk Assessment Procedure, ER&E Memorandum 93-CMS2-010, January 13, 1993.
DEFINITIONS
Definitions are provided in Appendix A and due to the importance of hose pressure ratings, this appendix provides a separate listing of hose pressure nomenclature.
INTRODUCTION GENERAL
Hose systems are the most common and basic cargo transfer system for connecting pier piping to tankers and barges for loading or discharge of crude oils and petroleum products. Cargo transfer systems comprised entirely of flexible hoses often provide the lowest cost facility with the greatest flexibility in accommodating marine vessels. Hose systems can range from a simple single hose string handled by a pier crane (or ship's boom) to more complex systems comprised of multiple hose strings supported and maneuvered from shore towers or gantries. Hoses can also be used in conjunction with swivels and piping to form a half-metal and half-hose system, sometimes referred to as "flow-boom".
PRODUCT SERVICE
Hose design practices are applicable for the transfer of the following product services:
• Crude Oil and Petroleum Products at temperatures ranging from –20°F (–29°C) to 180°F (80°C) for rubber hoses and 140°F (60°C) for composite hoses.
• Hot Asphalt and Sulfur at temperatures ranging from –20°F (–29°C) to 350°F (175°C) for rubber hoses. • Non-Refrigerated LPG Liquid or Vapor at temperatures ranging from –20°F (–29°C) to 115°F (45°C). • Vapor Recovery (excluding LPG Vapor) at temperatures ranging from –20°F (–29°C) to 140°F (60°C).
Hoses are not to be used for refrigerated LPG or LNG. These products are to be handled by marine loading arms per Section XXXI-F.
HOSES
The two main type of hose construction used at conventional (dock) marine piers and sea islands are referred to as Rubber hoses and Composite hoses. Rubber hoses are the conventional Oil Suction and Discharge (OS&D) hose used at petroleum terminals, while Composite hoses provide a lighter weight construction.
A third type of hose is of metallic (stainless steel) construction that is also of relatively light weight. Metallic hoses may be used at some marine terminals for specialty products, such as hot asphalt, special chemical products, or jumper hose in liquefied gas loading arms. Although many aspects of designing hose systems would apply to metallic hose, their use is unique and is not specifically covered by this design practice.
Rubber Hose
Standard rubber hose (OS&D hose) contains a tube or inner rubber liner and reinforcing components (Figure 1). The tube is the innermost part of the rubber hose body and protects the outer layers and carcass from contact by the product. Depending on the hose diameter and the products to be handled, the tube is either one or more rubber cylinders or sheets of rubber which are wrapped about a mandrel used to construct the hose. An inner steel reinforcement wire is often placed in the rubber hose to add strength and resist delaminating of inner layers. When the tube is placed over the wire reinforcement or the wire reinforcement is imbedded in the inner lining, the hose is referred to as a rough bore hose. When the inner steel reinforcement is not employed, the hose is referred to as a smooth bore hose.
The core or central component of the hose is referred to as the carcass and provides the hose strength against internal pressures, longitudinal tension, and other loads occurring from the handling and support of the hose. The carcass consists of various combinations of fabric and/or metal elements such as textile fabrics, wire reinforcement, flat steel rings, and woven cords. The outermost layer of the hose construction is called the cover and protects the carcass from abrasion, wear, and attack from the elements and/or chemical action. When the carcass does not use any wire reinforcement or steel rings but gains its strength from fabrics or woven cords, the hose is referred to as a soft-wall rubber hose.
Rubber hoses (OS&D) are cured (vulcanized) in ovens where the various layers are molded into a continuous hose body. Hose lengths are limited primarily due to the curing process, which requires ovens of sufficient length to accommodate the hose. Lengths are available up to 50 ft (15 m), but more typically are provided in 35 ft (10 m) lengths. Hose diameters can be provided up to 16 in. (400 mm), but generally are in the range of 4 in. (100 mm) to 12 in. (300 mm).
Flow rates for cargo transfer are not to exceed 50 ft/sec (15 m/s) for rubber hoses. This limitation is based on experience where higher flow velocities have been found to damage the interior lining.
Rough bore hoses are to be electrically continuous in that it is not practical to insure electrical insulation of the internal reinforcement wire. Smooth-bore and Soft-wall hoses can be manufactured either electrically continuous or electrically discontinuous.
End fittings are typically built-in nipples that are vulcanized into the hose body; however, swage fittings are becoming more common to reduce cost.
Composite Hose
Composite hose provides a light weight alternative to rubber (OS&D) hoses. Although not as robust nor having the durability of rubber hoses, composite hoses being lighter offer easier handling and lower initial cost. Composite hose is a tubeless hose made up of several layered components between internal and external spiral wire reinforcement (Figure 2). The hose is manufactured on a mandrel, first with the internal wire reinforcement, followed by several layers of synthetic films (polypropylene, polyester, synthetic fabrics), with a PVC impregnated cover, and finally the external spiral wire that lies between the spirals of the internal wire. The resulting hose construction has a corrugated appearance.
Recently some manufacturers have been marketing a cross between composite and rubber hoses by adding a rubber / vulcanized layer on the exterior of a composite hose. The additional exterior layer makes the hose somewhat more durable by providing protection against external physical damage. However, this crossbred hose should be considered and evaluated as a composite hose.
The multiple synthetic film layers provide the resistance to internal pressures, while the wire reinforcements hold the hose shape against internal pressure, longitudinal and other external loads. Since the hose is built up of synthetic material, composite hoses can be designed for chemical products that can not be handled with conventional rubber hoses.
The composite hose body can be manufactured in long lengths since it is not required to vulcanize the hose body. Lengths could be up to several hundred feet, which are then spooled into large rolls. Individual hoses are then cut to the desired hose length and end-fittings attached. Typical hose lengths are 35 to 50 ft (10 to 15 m) similar to rubber hoses, but longer lengths are available if required. Hose diameters typically range from 2 in. (50 mm) to 10 in. (250 mm).
Due to the method of construction, having the internal wire exposed to the product flow and layer of film wraps, the interior of the hose is susceptible to delaminating. Thus flow rates for composite hoses are not to exceed 23 ft/sec (7 m/s), nor should the hose be used for products having a viscosity exceeding 400 cSt (400 mm2/sec). These limitations are not well defined due to the
relatively limited experience with composite hoses. There is experience that flow rates above these levels can cause movement of internal wires, however some hose manufacturers note flow rates up to 33 ft/sec (10 m/sec) are permitted. However, due to the corrugated shape of composite hoses, pressure loss will be significant for flow rates at these limits.
Composite hoses must always be electrically continuous since the reinforcement wires can not be effectively insulated from end fittings. End fittings are always swaged fittings.
Metallic Hose
Metallic hoses are usually stainless steel bellows protected by one or two sheets of metallic braid. They are designed for a specific service such as hot asphalt (bitumen) and being lightweight are easier to handle than rubber hoses. Due to inspection difficulties, they have not been used at Exxon terminals. Consequently, design criteria / requirements have not been established. If metallic hoses are to be used, reference should be made to BS-6501 Flexible Metallic Hose Assemblies, Part 1 Specification
For Corrugated Hose Assemblies.
HOSE SYSTEM SELECTION
Hoses are commonly used for cargo transfer of crude oil and petroleum products. However there is another alternative, i.e. marine loading arms (Section XXXI-F) which requires consideration in defining the cargo transfer system for a particular facility. Selection of the cargo transfer system needs to first consider minimizing the risk of incidents. Since marine loading arms are deemed to be inherently safer, their use should be considered prior to selection of hoses. Loading arms are considered more reliable than hoses against catastrophic rupture; have less potential of wear / deterioration; and have a longer life expectancy.
HOSE VS. LOADING ARM
In some applications, loading arms are to be used where hose failure may present an unacceptable risk. Depending on the perceived risks, marine loading arms may be appropriate for hot asphalt and sulfur. Hoses are not acceptable for cargo transfer of refrigerated liquefied gas (refrigerated LPG or LNG), which requires loading arms at Exxon marine terminals. For pressurized LPG, hose may be considered provided the maximum spill size does not exceed 0.55 tons (0.5 metric tons). If cargo transfer piping can not be adequately isolated to preclude larger potential spills, then loading arms are required. Appendix B can be used for guidance on accessing the risk of using hoses for low volume transfer of pressurized gases.
Hose systems offer advantages that often can not be obtained with loading arms and are thus often the preferred system. Cost considerations are a key factor, particularly for small throughput volumes or where the utilization of the system is low. Physical parameters may also dictate use of hoses; such as movement / flexibility required in connecting to a vessel manifold. Terminal layout issues could also be a parameter particularly for an existing facility that is updating / replacing equipment where space and load carrying capacity of the terminal may not permit use of loading arms. Vessel parameters may also preclude use of loading arms, such as: where multiple a vessel's manifold connections require the cargo transfer equipment to occasionally cross over itself; where the vessel manifold cannot support the marine loading arm; or other vessel constraints that may prevent use of marine loading arms. Finally product quality requirements for segregation / contamination may require use of numerous separate systems which can not be accommodated with loading arms.
Hoses also have physical limitations, further described under HOSE SELECTION, which require consideration in their selection for a particular service. Primary considerations are limitations on hose diameters due to hose manufacturing capabilities and flow rate that can be physically tolerated by the hoses. Hoses are subject to chafing, crimping / kinking, and damage from being handled on dock facilities; thus the terminal layout / physical configuration may also influence the cargo transfer system selection. Unless mounted on fixed hose handling equipment, selection of hoses necessitates consideration of large deck areas for storage when not in use.
Depending on the number, size, and type of hoses; selection of the appropriate hose handling equipment would be selected as described under HANDLING EQUIPMENT. Choice of the optimum system for a particular location must consider the major operating conditions which the system must satisfy, and determine the best trade-off between investment, level of safety, and operating / maintenance costs. Table 1 provides a summary of advantages and disadvantages of the various cargo systems typically used at petroleum terminals. The major operating conditions to consider are:
• Range of vessel sizes to be accommodated • Product slate / simultaneous service • Tidal range
• Frequency of use
• Existing equipment and piping • Critical or specialty products handled
TABLE 1
CARGO TRANSFER EQUIPMENT ALTERNATIVES
EQUIPMENT TYPE ADVANTAGES DISADVANTAGES
Mast & Boom or Hydraulic
Telescoping Crane
• Requires least initial investment of all systems • Suited to low usage terminals servicing only
small barges
• Little control over bend radius, thus may experience kinking or crimping damage
• Generally limited to 8 in. (200 mm) diameter or smaller hoses, which may restrict loading rates
• Generally only 1 hose (possibly 2) can be hoisted at one time
• Hoses must be tended during transfer operation • Maneuvering and hookup / release procedures are
manpower intensive
• Sometimes requires assistance from ship's derrick Gantry Rig • Supplies relatively good support to the hoses
• Hoses are permanently rigged, reducing handling and associated wear or damage
• Usually limited to 10 in. (250 mm) diameter or smaller hoses, which may limit loading rates
• Maneuvering and hookup / release procedures are manpower intensive
• Hoses must be tended during transfer operation Metal / Hose
Systems • Eliminates hose bending / crimping problems • Retains most of the crossover flexibility of all
hose systems
• Can be designed for up to nominal 12 in. (300 mm) diameter
• Swivel joint on outboard end of hose reduces time and effort to hookup / release
• Counterweighted arms minimize deck space
• Systems must be tended during transfer operation • Not recommended for critical products
• Hose portion requires removal for testing
All Metal Systems • Metal construction provides safety against rupture
• Do not require tending during transfer operations
• Requires less manpower for hookup / release procedures
• Requires less maintenance • Counterweighted arms are easier to
maneuver
• Counterweighted arms minimize deck space • Minimizes risk of pollution
• Suitable for all types of products
• Initial cost usually higher than other systems • May require crossover manifolding on the pier
HANDLING EQUIPMENT
There are numerous different types of equipment designed to handle hoses during cargo transfer operations. The following are the major types of systems used by Exxon and a brief description:
• Mast and Boom
• Hydraulic Telescoping Crane • Gantry Rig
• Half-metal Half-Hose System (Flow Booms)
Mast and Boom
The mast and boom system (Figure 3) involves the minimum capital investment. This system also provides very little control of the bend radius of the hose and sharp bends and kinking often result. Eight in. hose is the largest that can be handled efficiently as the hose becomes to stiff to manipulate. Loading rates with this type of system are limited. The mast and boom system normally can handle only one hose at a time. Each hose must be handled separately and because the boom provides poor support for the hose, the ship's derrick often is used to help support the hose. Manual tending is required and normally, the hoses are not permanently rigged. This considerably increases the amount of handling and manpower required and reduces hose service life.
Hydraulic Telescoping Crane
Another hose handling system uses a standard hydraulic telescoping crane to maneuver the hoses to the ship for connections. Usually, hoses are stored by hanging them from a tower or a structure. The hydraulic crane is then maneuvered to lift the hose from the storage position and to maneuver the hose to the ship's manifold for a connection. After a connection is made, the crane can be used to support the hose during cargo transfer operations. It is very important with this type of system to use a properly designed sling system or "Hose Buns" to make the connection between the hose and the crane. The use of thin straps or improperly sized slings can cause severe damage to the hose by cutting the outer layers or displacing outer helix wires. A properly designed sling system will spread the lifting load along a greater surface area of the hose and thus avoids local damage to a particular section of the hose.
Gantry Rig
A gantry rig consists of a large structure equipped with winch-powered cables running over pulleys directly to the hose or to a jib boom or a "U" boom. Gantry systems (Figure 4) reduce the effort to maneuver hose and provides better support during cargo transfer operations. Gantries with jib booms can adequately handle 8 in. diameter hose while gantries with "U" booms are in service for up to twelve in. diameter hose. Manual tending is normally required during operation.
Half Metal – Half Hose
One form of half metal half hose systems consists of an inboard metal pipe leg joined to an outboard hose leg by a metal swivel joint or joints (Figure 5). A single or double metal swivel joint, permitting the required degree of rotation, connects the inboard pipe leg to a vertical dock riser pipe. The system is controlled either by an overhead "U" boom or by individual support cables leading directly from the arms to hoists mounted on the tower. A hydraulic crane can be used to supplement the flow boom system to maneuver the outboard hose.
HOSE SELECTION GENERAL
Hose system design is predicated on meeting specific terminal throughput requirements which are defined in developing the Marine Loading System as covered in Offsites Design Practice Section XXIII-A. Cargo transfer rates, loading and/or discharging, that need to be accommodated sets the basis for several of the service requirements and lead to defining the number of hoses and their size (diameter). In this regard, the cargo transfer rate needs careful consideration prior to the selection of hose requirements. Arbitrarily setting the basis equivalent to the maximum number of products / cargoes to be transferred simultaneously at the vessel's maximum loading / discharge rate is usually not the most optimum system.
Vessel loading and discharge rates need to be established considering data on both shore and vessel capabilities and limitations. Any one of several shore or vessel factors may limit loading rates. Shore facilities such as pumps, pipeline size and length, manifolding arrangements, metering and other equipment may limit loading rates. Likewise loading rates may be limited by vessel facilities including deck valving / manifolding, deck / tank piping size and length. Discharge rates are even more likely to be limited by the same considerations plus the limitations of the vessel's pumps and power supply.
Therefore the selection of hoses needs not only consider the physical limitations and service needs as defined in this section, but must also be based on throughput requirements, practical assessment of the overall cargo system requirements, and economic evaluations of terminal investment versus vessel / shore operating costs.
Selection of a hose type for a particular marine facility will depend on several factors involving the physical characteristics of the terminal, hose operating / maintenance parameters, service needs, and anticipated hose life expectancy. It is not possible to have a universally applicable set of criteria for all applications. This section provides information on the various criteria in defining the hose parameters. Table 2 provides a summary of those parameters which restrict the selection of hose type, i.e., Rubber or Composite, for size, pressure, product service, and electrical continuity.
TABLE 2
HOSE SELECTION PARAMETERS HOSE SELECTION RUBBER HOSE Design Temperature Range (Ambient or Product) Viscosity Limitation Minimum Rated Working Pressure (RWP) Minimum Burst Test Pressure Smooth Bore or Softwall Rough Bore COMPOSITE HOSE PERFORMANCE CRITERIA
°°°°F (°°°°C) cSt (mm2/s) psig (kPa) psig (kPa)
X Crude Oil and –20 to + 140 (–29 to + 60)
< 400 200 (1380) 4 x RWP
X X Petroleum Products –20 to + 180
(–29 to + 80)
N/A** 200 (1380) 4 x RWP
X X Hot Asphalt and Sulfur –20 to + 350
(–29 to +175) N/A** 200 (1380) 6 x RWP X X X LPG Liquid or Vapor (Non-Refrigerated) –20 to + 115 (–29 to + 45) N/A** 300 (2070) 5 x RWP X X Vapor Recovery (excluding LPG Vapor) –20 to + 140 (–29 to + 60) N/A** 150 (1035) 4 x RWP PHYSICAL
LIMITATIONS Flow Rate* Electrical Continuity End-Fittings
X X X < 23 ft/s (7m/s) X X < 50 ft/s (15 m/s) X X X Continuous X Discontinuous X X Built-in Nipples X X SwagedFittings
* Flow rate for static accumulator products are to be kept below 23 ft/s (7 m/s) unless prior experience permits rates up to, but not exceeding, 33 ft/s (10 m/s).
** N/A denotes Not Applicable
SERVICE REQUIREMENTS Operating Parameters
The primary operating issue is handling of the hoses. Where the elevation differences between the vessel and pier facility remain small even with vessel draft and tidal variations, handling hoses may be possible only with berth and vessel personnel. In these cases the hose may be subject to chafing / wear that requires a robust hose while at the same time minimizing hose weight is appropriate to reduce handling efforts. Unfortunately these factors do not work together. Rubber hoses offer more resistance to chafing / wear while Composite hoses are significantly lighter and easier to handle. The only offsetting aspect that helps in this selection is to minimize hose diameter to facilitate handling.
Terminals where a single hose string will meet the cargo transfer rate, but the elevation differences or hose diameter dictate a hose that can not be safely handled by personnel alone, requires use of mast and boom hose system. Even in this case, however, the hose may be subject to chafing / wear that requires consideration of a robust hose, while boom lifting capacity and ease of hose connection to the vessel may prompt the need to minimize hose weight. Thus the same trade-off between Rubber hoses and Composite hoses needs to be made. With the mast and boom facility, there is an enhancement that is sometimes applied to Composite hoses to provide chafing / wear protection. This amounts to wrapping the hose with rope to provide a protective wear surface.
Where several hoses may need to be handled / connected to a vessel, use of shore hose Handling Equipment is required. These systems can be used to maneuver / support several hoses simultaneously to permit multiple hoses to be used in obtaining higher throughput and cargo transfer rates. Also where the variation in height between the vessel and shore due to tidal variations and/or vessel height, hose handling equipment will be dictated in order to safely accommodate the hose weight.
Product
Even within the scope of PRODUCT SERVICE of this design practice, there are limitations for the various types of hoses. • Rubber hoses can generally accommodate all products, but require high temperature compounds for hot asphalt or sulfur
service. In vapor recovery service, use of rubber hoses is generally limited to smooth bore vs. rough bore due to the easier handling characteristics.
• Composite hoses due to their temperature limitations can not be used for hot asphalt and sulfur. The construction of Composite hoses also prevents this hose being used for viscous products having a fluid viscosity of 400 cSt (400 mm2/s).
Products having a viscosity exceeding this level can cause the internal wire to be displaced. In Composite hoses the internal wire is only held in position by hose corrugated configuration of layers of synthetic films and external wire compression. Otherwise, composite hoses can be used for all other products within the scope of this design practice.
• Metallic hose is generally limited to special services such as hot asphalt / sulfur or specialty chemical products.
Aromatics / MTBE
Hoses, being constructed of rubber and synthetic materials, are affected by the products they handle. Hose manufacturers have adopted materials that are highly resistance to crude oil and petroleum products, and if advised of the product to be accommodated will provide the appropriate liner material meeting industry standards.
The aggressive nature of aromatics and MTBE on rubber / synthetic liners, however, requires special consideration. Thus in selecting a hose for service, the percent aromatics or MTBE needs to be defined to insure the manufacturer selects and uses the appropriate liner in manufacturing the hose. Aromatic content is based on the total percent of toluene in the designated product. Hose material compatibility is tested by using toluene as the aromatic component.
S Electrical Continuity
Depending on the hose type, the hose may be manufactured as either electrically continuous or discontinuous. Electrically continuous hoses are those that have little resistance to electrical current, while electrically discontinuous hoses have a high electrical resistance. Electrical resistance is defined by means of a 500-volt megger or equivalent battery powered resistance meter.
• Electrically continuous hose measured flange to flange shall have a resistance not exceeding 0.25 ohm/ft (0.75 ohm/m). • Electrically discontinuous hose measured flange to flange shall have a resistance exceeding 750 ohms/ft (2500 ohms/m). Generally hoses are selected to be electrically continuous to insure the cargo system is grounded, see SHIP-TO-SHORE ELECTRICAL ISOLATION, DP XXXI-J. However, there are situations where electrically discontinuous hose are appropriate, see ELECTRICAL INSULATION of this practice.
Electrical properties are often dictated by the manufacturing process, particularly where there are internal reinforcement wires. Thus there are limitations as the availability of electrical properties for various hose types:
• Rubber hoses
+ Rough bore hoses are only manufactured as electrically continuous.
+ Smooth bore and softwall hoses can be manufactured as either electrically continuous or electrically discontinuous. • Composite hoses can only be manufactured electrically continuous.
Vacuum
Hoses can be subject to occasional vacuum during cargo transfer, particularly for vessel discharge when stripping operations are being conducted. This condition can cause internal liner deterioration such as bulging or separation of internal wraps. Fluid flow, particularly at high flow rates, can also cause separation of the inner layers if the adhesion between wraps is poor. Deterioration of the liner can affect flow and increase pressure loss. In the worst case, the liner may fail and cause complete blockage of the hose bore.
To assure quality of the inner liner, and adequate adhesion to the carcass, a vacuum design requirement is specified for the hose manufacturing of rubber (OS&D) hoses. The design requirement for rubber hoses is 25 in. Hg (– 85 kPa), which applies to rough bore and smooth bore hoses. Since softwall rubber hoses would collapse at this pressure, the vacuum requirement is not applied.
Composite hoses, having an internal reinforcement wire, would be resistant to vacuum and thus are not specified nor tested for vacuum conditions.
Bend Radius
Being a flexible system between the shore and vessel, the hoses must have the ability to bend in response to the changing elevations of the vessel and to facilitate connections between shore and vessel. Acceptability of hose bending is measured by the hose Minimum Bend Radius Ratio (MBR Ratio). MBR Ratio is the ratio of the hose bending radius at its maximum allowable bend, referred to as the Minimum Bend Radius, to the hose nominal diameter.
Minimum Bend Radius is a measure of the smallest radius around which a hose can be bent without mechanical damage or permanent deformation. The radius is measured to the innermost surface of the bent section.
The MBR Ratio = MBR/Hose nominal diameter, both in the same units of measure. MBR Ratio for hose shall not exceed:
• 6:1 for Rubber hoses. Note that softwall hoses would collapse without internal pressure, and thus are to be tested with an internal pressure of 50 psi (345 kPa).
• 4:1 for Composite hoses.
PRESSURE RATING
To provide a secure containment of product during the cargo transfer operations, the individual hoses need to be designed for pressures that may occur during loading / discharge of the vessel. This includes not only the expected or normal operating pressures, but also must cater to higher pressures that may be caused by pump shut in or surge pressures if there were a sudden restriction or shutdown of the cargo system.
In defining the design pressure, it is important to have a clear definition of the pressure ratings since common nomenclature for vessel and shore, as well as between industry standards may actually have different meanings as the specific pressure requirement. Appendix A provides a listing of pressure designations and their common use application.
The two primary pressure ratings used by Exxon are the Rated Working Pressure (RWP) and Burst Test Pressure. These two pressures are used to define hose manufacturing requirements.
Rated Working Pressure
Rated Working Pressure (RWP) is the maximum operating pressure at which a hose is designed to be in service. If the cargo transfer system had a pressure relief valve, the RWP would equal the setting of the pressure relief valve. If the system does not have a pressure relief valve, RWP would equal the maximum pump pressure plus static head. RWP excludes surge pressures.
Minimum values of RWP for dock hoses in Exxon service shall be:
• 200 psi (1380 kPa) for all liquid crude oil and petroleum cargo transfers, either loading-to or discharging-from any marine vessel.
• 300 psi (2070 kPa) for non-refrigerated (pressurized) LPG liquid or vapor service. • 150 psi (1035 kPa) for non-LPG cargo vapor service.
The 150 psi requirement for non-LPG vapor service is unique in that the normal vapor recovery system pressures are low, often less than 5 psi (35 kPa). However, the vapor hose must have sufficient reinforcement to withstand the handling conditions typically found at marine terminals. Although a lower pressure rating may be possible, the durability requisite for vapor hose justifies the use of the higher RWP rating.
The recent issuance (1998) of European Standard EN-1765 on dock hoses, and the pending endorsement of this standard by OCIMF, will affect the Exxon design requirement in specifying hoses but will not affect the physical requirements for hoses used by Exxon. The new hose standard uses "Test" pressure to define the design / manufacturing requirements. The "Test" pressure would nominally be equivalent to 1.5 times RWP.
S Burst Test Pressure
Burst Test Pressure a design / manufacturing requirement as to the internal hose pressure that the hose must achieve prior to the failure of any part of the hose resulting in a leak, rupture, separation or distortion in any part of the hose body or with its end-fittings. This requirement provides a safety factor to insure hose performance over its life even with normal wear and deterioration. This pressure must be held for 10 minutes during PROTOTYPE TESTING for successful completion of this requirement. The hose's actual burst pressure is determined by increasing the internal pressure until the hose fails.
Burst Test Pressure is defined as a multiple of the hose Rated Working Pressure (RWP). Minimum Burst Test Pressures for dock hoses in Exxon service shall be:
• 4 x RWP for all liquid crude oil and petroleum cargo transfers, either loading-to or discharging-from any marine vessel, excluding hot asphalt and sulfur.
• 6 x RWP for hot asphalt and sulfur cargo transfer operations.
• 5 x RWP for non-refrigerated (pressurized) LPG liquid or vapor service. • 4 x RWP for non-LPG cargo vapor service.
The recent issuance (1998) of European Standard EN-1765 on dock hoses, and the pending endorsement of this standard by OCIMF, will affect the Exxon design requirements for Burst Test pressure. The new hose standard uses a factor of 4 on "Test" pressure to define the requirements for Burst Test Pressure for the hose design. The use of this requirement would be equivalent to requiring all hoses be burst tested to 6 x RWP if the equivalent "Test" pressure is 1.5 times RWP.
FLUID FLOW
The physical construction of hoses, being made of rubber and synthetic materials, leaves the hose vulnerable to wear and deterioration from fluid flow. This is similar to steel pipelines, but more pronounced, where the abrasive nature of the fluid causes wear from friction, turbulence and cavitation. Hoses being used as a flexible conduit also results in changes in direction of fluid flow that, along with compression / stretching of the internal hose liner, will aggravate the situation.
Flow Rate
Flow rate is limited to prevent deterioration and failure of hose liners which can lead to leakage, hose burst failure, or separation of the inner liner. The latter situation could result in complete blockage of the fluid flow causing sudden surge pressures in the cargo transfer system.
Flow rates limitations are empirical, based on past industry experience. Although variations can be tolerated, most hose manufacturers limit the service of their hoses to these established industry practices. Therefore the following maximum flow rates should be considered in defining a hose system, unless a specific hose type / manufacturer has been consulted.
• 50 ft/sec (15 m/sec) for Rubber hoses (rough bore, smooth bore, softwall). • 23 ft/sec (7m/sec) for Composite hoses.
S Hose systems handling "static accumulator" products shall be designed to limit the maximum flow rate. Petroleum products that are static accumulators can generate and hold a static charge. Fluid flow through piping, especially hose, systems generate a static electricity charge as a function of diameter and velocity. This electrical charge will dissipate (release) after a residence time in the vessel / shore tank. However, this charge could present a safety risk if it is of sufficient magnitude and rapidly dissipated where it could cause an incendiary spark. Experience indicates that hazardous electrical potentials do not occur if the velocity is below 23 ft/s (7 m/s), and this is a statutory requirement by some national codes. Where documented experience indicates higher velocities have been used safely, the limit of 23 ft/s (7 m/s) may be increased. However for Exxon marine terminals, the maximum flow rate for static accumulator products shall not exceed 33 ft/s (10 m/s).
Pressure Losses
Pressure drop due to fluid flow in hoses is treated as if the system were a pipeline. However due the increase resistance of the hose internal liner, as well as the hose not being a straight conduit, the pressure drop will be considerably more than a pipe section of equal length. As hoses are constructed differently, both in type and by manufacturer, it is not possible to define a specific procedure to calculate pressure drop.
In designing a hose system, the nominal pressure drop should be considered to have a minimum increase in pressure drop of 20% in comparison with equivalent length of steel pipe. For Rubber hoses of rough bore construction, this nominal pressure drop needs to be increased by another 10% to cover the additional pressure losses caused by the increase resistance to flow in these hoses. For Composite hoses, the pressure losses can be significantly higher due to the corrugated configuration of these hoses. A minimum increase of 5 times the nominal pressure drop should be considered for these hoses. Where a specific hose will be used, the manufacturer can be consulted on the estimated pressure drop.
DIAMETER
Due to the nature of manufacturing, hose diameters typically vary within a tolerance of +/– 2%. Thus hoses are usually referenced by their nominal diameter which is specified within the nearest 2 in. (50 mm). Although the use of nominal diameter will not generally affect the hose design, the selection / purchase of specific hoses should check the manufacturer's specific hose diameter.
Hoses for general conventional pier (dock) service should not be smaller than 4 in. (100 mm) in diameter. Hoses smaller than this are not suited to connection to most vessel cargo manifolds, and are easily subject to kinking. For specialty service, such as bunkering of small marine craft, smaller hoses have been used if mounted on reels along with provisions to prevent kinking as the hose is bent over dock edges. This design practices and IP 3-11-1 are not applicable for hoses less than 4 in. (100 mm) in diameter.
The maximum hose diameter should also be limited due to the cost in providing proper lifting equipment as well as the difficulty in handling / connecting hoses to the vessel. Rubber hoses, due to their weigh and difficulty in handling, are generally limited to 12 in. (300 mm). Composite hoses are limited to a maximum diameter of 10 in. (250 mm). Even though lighter in weight for handling, composite hoses have not been found to provide the robustness / strength necessary for hoses more than 10 in. (250 mm).
LENGTH
Selection of the reach of a hose string for a specific application will depend on the marine terminal's physical configuration, the vessels to be accommodated, and water height (tidal and/or river stages) variations. These factors are considered to define the maximum reach which is required between shore and vessel while keeping the bending of the hose in excess of its Minimum Bend Radius (MBR) Ratio. Since hoses nominally come in standard lengths of 30 to 35 ft, or 50 ft (10 m or 15 m), the defined reach is rounded up to that length made up of nominal hose lengths.
To determine the total reach requirement of the hose system, an Operating Envelope is typically used to define the extent of variations between the pier manifold and the manifold of vessels calling at the terminal. With this Operating Envelope, estimates are made of the necessary hose reach to match any position within this envelope.
Once the hose length is determined, checks should also be made to insure the hose-handling crane or boom is sufficient to facilitate the handling of the hose from any position in the operating envelope. Guidance on Crane / Derrick Reach is provided in this section.
Operating Envelope
The operating envelope is the volume in space which contains all the expected vessel manifold positions during the cargo transfer including allowance for tidal changes, vessel drift off the pier, surge along the pier, and the range of vessel manifold locations. It is actually made up of two separate envelopes, the “Working Envelope", and the “Drift Envelope" as shown in Figure 6.
The working envelope contains the space which includes all the possible positions that the ship's manifold might reach during normal operations and must account for variability in the position of manifolds on the decks for the entire range of vessels calling at the terminal, as well as the range of vessel elevations due to changes in draft from loading or unloading or changes in tide or river stages.
The drift envelope is an additional allowance to account for abnormal movement of the ship in the berth, usually caused by environmental forces acting on the vessel. For new sites, the allowances given in Table 3 and shown in Figure 6 should be used. At existing sites, these allowances are normally based on the terminal's experience and is consistent with that used for the existing systems, provided the allowances are at least equal to those which would be specified for a new site.
TABLE 3
VESSEL DRIFT AND SURGE ALLOWANCES
A Drift Movement perpendicular to berth (normally caused by wind, passing ship effects, or a combination of the two).
10 ft (3 m) B Surge Movement along the berth in either a forward or astern direction
(normally caused by current or a combination of current and wind). 10 ft (3 m)
The Operating Envelope is developed considering the vessel's manifold will be correctly centered (spotted) on the pier hose system. If multiple hoses will be connected, they are generally centered on the vessel's manifolds in that shore manifolds have nominally the same spacing as vessel manifolds. The Drift Envelope is considered to adequately account for variations in vessel manifold spacing and spotting offsets. However additional hose system length may be appropriate to cater to specific / unique situations. The governing conditions for the operating envelope parameters are shown schematically in Figure 7 and listed in
Table 4.
TABLE 4
OPERATING ENVELOPE GOVERNING CONDITIONS
Left Edge Maximum Vessel Stern Surge Allowance
Bottom Smallest Vessel, Fully Loaded, at Lowest Low Tide Top Largest Vessel, Fully Light, at Highest High Tide Inside Edge Smallest Manifold Setback
Outside Edge Largest Manifold Setback plus Maximum Vessel Drift Allowance Right Edge Maximum Vessel Forward Surge Allowance
Table 5 can be used to collect the required data to develop the Operating Envelope. Some of this data can be generated from
the Marine Engineering Section's “Vessel Log" computer program; other information must be supplied by the affiliate specific for the pier facility.
TABLE 5
DATA REQUIREMENTS FOR OPERATING ENVELOPE
Berth Data Required Elevation of Pier Deck
Distance from Pier Manifold to Fender Face Environmental Data Required
Highest High Water Elevation Lowest Low Water Elevation
Ship Data Required Minimum Ship Maximum Ship
Ship Size (DWT) Fully Light Freeboard Minimum Manifold Setback
Minimum Manifold Height Above Deck Fully Loaded Freeboard
Maximum Manifold Setback
Data Provided for Operating Envelope
An example on developing the Operating Envelope is provided in Figure 8 with the resulting envelope illustrated in Figure 9. Data requirements for a range of vessels is presented as would have been collected using Table 5. This data is schematically presented in Figure 8 and illustrates how the vessel cargo manifold positions are obtained. Figure 9 illustrates the Operating Envelope that results from the example problem using the vessel governing conditions for vertical elevations (Figure 8) and the vessel drift and surge allowances defined in Table 3.
Reach
Using the Operating Envelope, the total hose string length requirement is defined by the maximum length required to reach all positions within the envelope. This is nominally done by schematically sketching the position the hose would take reaching the edges of the operating envelope with allowance for bending of the hose. In developing the sketch, hose bending must maintain a MBR greater than that for the hose type selected. The hose length is then measured along the sketched position, with the maximum length defining the reach requirement.
Crane / Derrick Reach
Since the hose handling equipment is used to support the hose in connecting and disconnecting from the vessel, the crane / derrick must have the capability to match the hose configuration anywhere in the operating envelope. In addition the crane / derrick equipment needs to have additional reach / extension to facilitate hose lifting / positioning to the vessel manifold as well as possibly extending over other restraints, such as the vessel's railing. If hose storage is on a hose tower or gantry, it will also be necessary for the crane / derrick to reach to and above these facilities.
For general guidance, the crane / derrick reach should have a reach / extension of 5 ft (1.5 m) beyond the defined area of operation, i.e., the operating envelope and/or hose gantry or tower reach requirements.
LIFE EXPECTANCY
When properly used and maintained, hoses will provide a secure and dependable system for cargo transfer. However hoses will deteriorate from both handling and cargo flow. Therefore in comparing hose systems to marine loading arms, consideration must be given to the cycle on hose replacements. Nominally the hoses should provide reliable service to their retirement age, after which they are to be removed from service and replaced with new hoses.
Hose retirement age criteria is presented in Table 6 and should be used in defining new hose systems unless specific affiliate experience justifies amended retirement criteria. The criteria define a nominal hose retirement age and a maximum retirement age.
TABLE 6
HOSE RETIREMENT CRITERIA
HOSE RETIREMENT AGE (YEARS)(1) SERVICE
RUBBER (SMOOTH BORE) RUBBER (ROUGH BORE) COMPOSITE
Oil & petroleum products 6 6 4
Hot asphalt & sulfur 2 2
LPG liquid or vapor (non-refrigerated) 3 3 2 Vapor recovery (excl. LPG vapor) 7 — 5 MAXIMUM AGE(2) 12 12 8 Notes:
(1) Adjust recommended Retirement Age (Years), up to Maximum Age, according to Hose Duty Classifications of Tables 7 and 8
as follows:
(i) Medium duty (M): no adjustment (ii) Light duty (L): + 50% (iii) extra Light duty (XL): + 75% (iv) heavy duty (H): – 50% (v) extra Heavy duty (XH):– 75%
Nominal Retirement Age
The nominal retirement ages range from 2 years to 7 years. However the nominal retirement age values of Table 6 may be adjusted for the following operating factors that have been assessed to influence retirement age:
• hose pumping hours • fluid flow rate • handling procedures
Increased pumping hours or flow rates will reduce hose retirement age. Handling of hoses on the pier deck without permanent support from a hose tower / gantry will also reduce hose retirement age (Table 7). Hose permanently mounted on a hose tower / gantry are deemed to have less risk of damage or abuse due to over-bending, impact, or dragging on the pier deck and fender systems (Table 8).
TABLE 7 DOCK SERVICE MAX. PUMP TIME
hrs/yr HOSE DUTY CLASSIFICATION
5000 H H XH
4000 H H H
3000 M H H
2000 L M M
1000 L L L
Max. Fluid Velocity 23 fps (7 m/s) 40 fps (12 m/s) 50 fps (15 m/s) Notes Rubber &
composite hose types Rubber hose types only Rubber hose types only TABLE 8 TOWER-SUPPORTED SERVICE MAX. PUMP TIME
hrs/yr HOSE DUTY CLASSIFICATION
5000 M H H
4000 M H H
3000 L M H
2000 L M M
1000 XL L L
Max. Fluid Velocity 23 fps (7 m/s) 40 fps (12 m/s) 50 fps (15 m/s) Notes Rubber &
composite hose types Rubber hose types only Rubber hose types only
Maximum Retirement Age
A maximum retirement age has been set to prevent continue use of hoses even where they have not been subject to extensive use or abuse. This is because hoses, being manufactured from rubber / synthetic materials, will degrade naturally due to the environment, particularly ozone and heat. The maximum age is defined as the age of the hose from its date of manufacture (Table 6).
HOSE END-FITTINGS
Hoses can be manufactured with two types of end-fittings: Built-in Nipples, or Swaged fittings. The traditional end-fitting developed with Rubber (OS&D) hoses was the built-in nipples. Development of the Composite hose, lead to the swaged fitting which has subsequently been applied to Rubber smooth bore and softwall hoses.
The end-fitting would be assembled with the appropriate flange connection as specified for the specific use. All materials for the end-fitting should be of Grade B seamless, black finish, carbon steel conforming to ASTM A106, ASTM A53, or API 5L. Aluminum is not permitted for dock hose end-fittings.
Built-in Nipples
Built-in Nipple (BIN) end-fittings (Figure 10) shall be standard pipe weight for the hose nominal bore. BIN shall have at least two raised rings on the exterior where the hose carcass will be assembled. In the assembly, the rubber hose liner will be placed over the BIN with adhesives to provide a positive seal when the hose is vulcanized (cured). Flanges are generally made up to the BIN prior to the manufacture of the hose. BIN end-fittings are available only with Rubber hoses.
Swaged Couplings
A swaged coupling (Figure 11) is an external compression fit, where the hose body is compressed between the steel tailpiece and an external compression collar (ferrule). The tailpiece will be serrated / grooved and inserted into the hose, sealant material added, and the external collar fitted over and compressed onto the tailpiece. The collar (ferrule) shall have a minimum nominal thickness of 0.25 in. (6.4 mm) for liquid service. For hoses to be used in vapor service (excluding LPG vapor), the collar (ferrule) shall have a minimum thickness of 0.18 in. (4.7 mm).
To provide a consistent and acceptable / reliable seal using swaged fittings, Exxon requires the process be done with a hydraulically operated compression facility as opposed to a manual fitting, either screwed or manually (gear) operated compression.
Swage fittings shall not exceed 10 in. (250 mm). Swage fittings are available only for Composite hoses and Rubber smooth bore and softwall hoses.
FLANGES
Hose flanges shall be of steel meeting ASME B16.5 Class 150 and flange material shall conform to ASTM A105. Flanges for LPG service shall be Class 300.
Flange attachment to the BIN nipple or Swaged Fitting tailpiece shall be specified as either weld neck flange with full penetration welds or slip-on flange with double fillet welds. To facilitate connection to the vessel manifold and reduce torsion in the hose, use of rotating flanges can be considered. Flanges should have a raised face (RF) finish unless specified by the affiliate as flat face (FF).
Welding shall be in accordance with API Standard 1104 and ASME IX. The welders symbol shall be die stamped on the flange of every fitting. All welding on end fittings shall be completed prior to the end fitting being made up with the hose. Welding of end-fittings for LPG service shall be 100% radiography inspected.
To prevent cross-connection of vapor and cargo product lines, consideration should be given to the requirements of API RP 1124, which specifies the user of lugged keying mechanism for the vapor presentation flange and, hence, the vapor hose flanges.
Bolting
Bolting of flanges is generally employed for connections to the pier piping, between individual hose lengths, and to the vessel cargo manifold. Bolts shall of steel meeting ASTM standards for the flanges being used.
For all flange connections (including vessel connection), bolting shall be completed with: • A single gasket
• Proper size bolts for the flange • Bolt in every hole
• Without short bolting (bolt threads extending beyond bolt)
Gaskets
Every new hose system connection, including opening / closing of existing connections, shall be made with use of a new gasket. Requirement for a new gasket applies to hose connections to a vessel manifold.
Couplers
Couplers are mechanical devices attached-to or used in lieu of standard flanges to facilitate hose connection to a mating flange. Couplers are used to eliminate bolting in connection / disconnection of hoses to enhance efficiency. Use of couplers are not deemed to enhance safety nor, although easier to make / break, do they provide an emergency disconnect feature.
Application of couplers requires specific requirements to insure they provide a secure connection. These requirements are the units be manufactured of steel (similar to flanges), and that the coupling device have a "locking" feature to prevent the coupling mechanism from loosening from vibrations or inadvertent disconnection. The locking feature must be such that unlocking can only be done by physically disengaging the lock mechanism. This requires a latch or pin type device as opposed to a screw or over-cam mechanism.
Some couplers will also come with their own built-in seal face that is acceptable if it will engage the seal face of the mating flange. In selecting units with built-in seals, care must be exercised to insure the coupler and mating flange are of the same size / standard.
S ELECTRICAL INSULATION
Insulation is required in hose strings to prevent electrical current from passing between the ship and shore. Although such current can seriously disrupt the berth’s cathodic protection system, the main reason for preventing the flow of this electrical current is to prevent sparking when the current path is broken as the hose is connected or disconnected from the ship. Hydrocarbon vapors are present inside the drained hose, along with oxygen which enters through the joint as the connection is made or broken. Conditions are, therefore, present which can lead to explosion, and it is very important to ensure that sparking is not allowed to occur.
Insulation may be achieved by use of an insulating flange or by the use of one electrically discontinuous hose. An insulating flange is preferred for use with static accumulators as electrically discontinuous hose allows static charge to build up. It is possible to use electrically discontinuous hose as the last length of hose in a string to achieve insulation, but this could lead to confusion with the different types of hose being used if it is not obvious which is which. Using insulating flanges shows visibly that the system is insulated. Figure 12 shows an insulating flange inserted in a hose string. Figure 13 illustrates two types of insulating flanges.
PROTOTYPE TESTING
Hose systems shall be made up of hoses whose performance has been certified through prototype testing of the specific hose type. Prototype testing, which includes normal production type tests and a burst test to failure, shall be made prior to use of the hose in an Exxon system. The prototype tests can be waived provided that:
• Selected hoses to be used are identical in construction / design of previously prototype tested hoses. • Previously prototype tested hose was within 10 years of date of order of selected hoses.
• Certified test data for previously prototype tested hose is submitted upon request.
APPROVAL TESTS
The manufacturer shall carry out the test as defined in IP 3-11-1 on each new type and modified design of the hose using the largest bore in the manufacturer's range of each hose type. Approval tests are for the specific manufacturing plant as well as the hose design. Thus the same hose design manufactured at another plant would also require prototype testing.
The hose subject to the test shall have a minimum length of 10 ft (3000 mm).
CERTIFICATION
The test results shall be stated on the prototype test certificate. Certification of the tests shall be conducted by Exxon Quality Assurance or a qualified, independent inspection service. Certifications are considered valid for a period of 10 years, after which the prototype test shall be redone even if the design remains unchanged.
PRODUCTION TESTING
Each hose used in the hose system shall be subject to tests after its manufacture at the plant and upon receipt at the terminal site. The tests are intended to better detect manufacturing defects prior to acceptance, as well as insure the hoses have not been damaged in transit to the terminal site.
APPROVAL TESTS
Tests conducted at the plant, referred to as Production Tests, shall be as specified in IP 3-11-1. The tests are non-destructive and would be conducted annually as a normal integrity check of the hoses. The same tests, excluding the bend test, are normally conducted of each hose when it arrives at the terminal to insure in has not been damaged in transit and is ready to be put in service.
TEST CERTIFICATES
Test certificates for each hose covering the production test results shall be provided by the manufacturer. Test certificates shall clearly identify the specific hose, its marking details, and serial number and the results of each test defined in IP 3-11-1. The affiliate can elect to have these tests witnessed by an independent third party or accept the manufacturers quality assurance program.
Welding qualification procedure specification and records shall also be submitted for each order of hoses.
PURCHASING
The design / selection of the appropriate hose system requires that the hose(s) be purchased and provided to meet specific criteria defined in the design. IP 3-11-1 provides a concise summary of manufacturing requirements which can be used in purchasing hoses to meet Exxon requirements as defined in this Design Practice. The International Practice is intended to reduce the risk of cargo transfer hose failures that are the result of poor manufacture or improper user specification of hose service conditions.
IP 3-11-1 covers composite hoses and all types of rubber hoses, and thus it is necessary to identify the particular type of hose being purchased. Also definition must be provided on specific design requirements for hose diameter, length, pressure rating (RWP), electrical continuity, and end-fittings. A data sheet for purchasing of hoses, Table 9, has been developed to facilitate the hose definitions appropriate to selected design of the hose cargo transfer system. This data sheet is included in IP 3-11-1 for use in purchasing hoses. It is not intended for offshore hoses nor hoses used for truck or rail loading.
MARKING
Each hose shall be permanently and legibly marked as specified in IP 3-11-1. In specific situations, the affiliate may request additional markings that shall be incorporated into the manufacture of the hose.
PREPARATION FOR SHIPMENT
Hoses shall be palletized for shipment whether the hose is laid out straight or coiled / rolled to prevent damage / abrasion during shipment. Hoses body shall be adequately supported to prevent kinking or other deformations. Flanges shall be protected over the entire gasket surface with metal, hardboard, or solid wood flange protectors.
STORAGE
If a new hose will not be placed in service, it should be placed in storage to protect the hose and extend its service life. Ideally hoses should be stored on racks to provide support and keep the hoses off the ground / floor of the storage area. If racks are not available the hoses should be laid out straight in a relax manner. Where the hose must be coiled, the radius should not be smaller than twice the hose MBR.
The storage should preferably be a dark, cool, and well ventilated area. Protection from the sun is a primary consideration to avoid ultraviolet light damage as well as heat. Cool temperatures are preferably for storage of hose, but should be less than 100°F (38°C). Hose should be kept on a dry surface avoiding any oil or other liquids.
TABLE 9
DATA SHEET FOR PURCHASING HOSE Hose Description (specified by Purchaser) Purchaser:_____________________________________________
Project Title: ________________________________________ Terminal / Vessel:_____________________________________ Berth / Pier:__________________________________________ Service: ___________________________________________ Operation: • Berth • Hose Tower • Floating
• Barge • Ship • Lightering
Manufacturer: _________________________________________ Hose Type: • Rubber - Smooth Bore • Softwall
• Rubber - Rough Bore • Composite Hose Diameter, in. (mm): ________________________________ Hose Length, in. (mm): _________________________________ Order / Purchase Record No.:______________________________ Order / Purchase Record Date:_____________________________ Design Data (specified by Purchaser)
Product(s): _________________________________________ Aromatics (%): ______________________________________ Other Component (specify): ____________________________ Rated Working Pressure, psi (kPa): _____________________ Electrical Continuity: • Continuous
• Discontinuous
Marking Requirements a): ______________________________ b): ______________________________
Performance Requirements per 1.1 and 4.1 unless noted below: Temp. Range, °F (°C): __________________________________ Rated Burst Pressure, psi (kPa): __________________________ Vacuum Rating, in. Hg (kPa): ____________________________ Max. Flow Velocity, fps (m/s): ____________________________ Min. Bend Radius, in. (mm): ______________________________
Manufacturer’s Data Hose Model: ________________________________________
Date Manufactured: __________________________________ Location Manufactured: _______________________________ Design Standard / Type:________________________________ Hose Serial No.: _____________________________________ Prototype Min. Burst, psi (kPa): ________________________
Min. Bend Radius in. (mm): _______________________________ Hose Weight, lb/ft (kg/m): _______________________________ Bore Diameter, in. (mm): ________________________________ Temp. Range, °F (°C): __________________________________ Certification By: _______________________________________ Certification Date: ______________________________________ Construction/Material Specification (or attach detailed drawing)
• Rubber Hose • Composite Hose
a) Liner Material & Thickness:
_________________________________________________ b) Reinforcement Material & No. Layers:
_________________________________________________ c) Wire Diameter & Tensile Strength:
i) Body Wire: ___________________________________ ii) Internal Wire (Rough Bore):________________________ d) Cover Material & Thickness:
_________________________________________________ e) End Fitting: • Built-in Nipple • Swaged
a) Tube Material & No. Layers:
_________________________________________________ b) Barrier Layer Material & No. Layers:
_________________________________________________ c) Reinforcement Material & No. Layers:
_________________________________________________ d) Wire Diameter & Tensile Strength:
i) Internal Helix: ________________________________ ii) External Helix: ________________________________ e) Cover Material & Thickness:
_________________________________________________ Flanges (specified by Purchaser)
a) Rating: • 150 ANSI • 300 ANSI
b) Type / Attachment: • Raised Face • Flat Face • Weld Neck • Slip-on Manufacturer’s Test Data
Test Pressure Po = 10 psi (70 kPa) Pt = 150% RWP = Pp = 10 psi (70 kPa)
Length Lo = Lt = Lp =
Elongation (%) Et = Ep =
Hose handling considerations should be reviewed during the development of the hose system. These aspects will insure the hoses will perform properly and provide a secure cargo transfer system.
For application of handling equipment, the individual hoses should be provided with adequate support via hose straps or hose saddles. Where hose straps are used from a single support, two straps should always be provided and arranged to have an angle between the straps of approximately 30°.
Where the hose will be laid across the terminal and ship, support may need to be provided to avoid excessive bends or possible contact with sharp edges. If possible avoid having the hose touch the pier or vessel deck during cargo transfer. Placement of dollies or pads under the hose will help prevent chafing against the pier and vessel decks.
Avoid designs where the hose may droop between the vessel and pier. Similarly hot surfaces, such as steam pipes, need to be avoided in planning the hose system.
Schematic diagrams illustrating appropriate hose handling arrangements and those which should be avoided are illustrated in Figure 14.
ROUTINE INSPECTION AND TESTING
Provisions for routine and ongoing inspection and testing of hoses needs to be considered in the design of the hose system. Since hoses are subject to damage / wear / aging, they will need to be inspected and replaced on a regular basis. The facility design should permit the hose to be visually examined for damage prior to each use in cargo transfer service. The hose system design must also consider the hoses require annual pressure testing and inspection, which will require the hoses be removed from any handling equipment and placed on the pier deck. Hose replacement, due to damage / wear / age, will also necessitate the hose system be designed to facilitate the ease of hose replacement.
Specific guidance on routine inspection and testing of the hose system is covered in EE.132E.95, Marine Terminal Inspection
RUBBER HOSE CONSTRUCTION DP31Gf01 Liner (tube) Carcass Cover FIGURE 2
COMPOSITE HOSE CONSTRUCTION
EXTERNAL COVER
• Abrasion and Ozone Resistant EXTERNAL WIRE
• Protrudes Above Cover • Lies Between Internal Wire INTERNAL WIRE
• Lining Placed Over Wire • Lies Between External Wire
LINING
• Synthetic Reinforcement Fabric LAYERS
Multiple Layers of Synthetic Film
• 42 in. wide Polypropylene Fabric (0.025 in. thick)
MAST AND BOOM HOSE HANDLING SYSTEM
GANTRY RIG HOSE HANDLING SYSTEM
HALF METAL – HALF HOSE HANDLING SYSTEM
Hose Operating Envelope
OPERATING ENVELOPE CL Drift Envelope Working Envelope Berth A 10 ft (3 m) ELEVATION VIEW Working Envelope Drift Envelope PLAN VIEW 10 ft (3 m) B B 10 ft (3 m) DP31Gf06
OPERATING ENVELOPE GOVERNING CONDITIONS Right Edge Bottom Outside Edge Left Edge Top Inside Edge DP31Gf07
