Static Charge Isolation on Vessels STATIC CHARGE ISOLATION

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Static Charge Isolation on Vessels STATIC CHARGE ISOLATION ON VESSELS 58 th Annual MARINE

Static Charge Isolation on Vessels STATIC CHARGE ISOLATION ON VESSELS 58 th Annual MARINE CHEMIST ASSOCIATION SEMINAR 26 July 2016 Hilton Savannah De. Soto Hotel 15 E Liberty St, Savannah, GA 31401 Bob Kamb, Managing Partner 1

DISCLAIMER Although Mystic River Partners LLC and its Principals, employees and representatives make every

DISCLAIMER Although Mystic River Partners LLC and its Principals, employees and representatives make every effort to ensure the accuracy of the information presented herein, no warranty, express or implied, including with respect to the correctness or completeness of the material, data, information and conclusions within this presentation is made. Mystic River Partners LLC will not be liable for reliance or usage by any third party of any information contained in this presentation. “Education is what survives when what has been learnt has been forgotten” – B F Skinner, 1964 2

ELECTROSTATIC HAZARD Tanker and tank barge explosions in which static discharge was a probable

ELECTROSTATIC HAZARD Tanker and tank barge explosions in which static discharge was a probable cause have refocused attention on electrostatic hazard The problem is broad-based, including marine shipping, shipyards and shore-based industries involved in vessel maintenance and repair. There is ample documentation in place describing safety precautions 3

INCIDENTS American Eagle GOM, 1984 Bouchard Barge #125, Staten Island 2003 Bow Mariner Norfolk,

INCIDENTS American Eagle GOM, 1984 Bouchard Barge #125, Staten Island 2003 Bow Mariner Norfolk, VA 2007 Stolt Valor, Persian Gulf 2012 4

CAUSE Isolated Conductors: objects that are either inherently or accidentally insulated from ground: •

CAUSE Isolated Conductors: objects that are either inherently or accidentally insulated from ground: • Pipework- metal flanges, fittings and valves • Portable containers and vessels • Ship cargo tanks, Tanker trucks, rail cars, intermediate bulk containers Basic Steps: 1. Charge Separation – interface of two dissimilar materials • Liquid flowing through pipes – filters – contaminants – settling – gas bubbles – turbulence – splashing 2. Charge Accumulation-Static charge accumulates on the object • Poor electrical conductors impede recombination of separated charges 3. Electrostatic discharge – sudden breakdown of insulating material • Sudden flow recombination generates intense local heat – spark- that becomes source of ignition 5

Solutions Bonding is the process of electrically connecting, by wiring or direct contact, conductive

Solutions Bonding is the process of electrically connecting, by wiring or direct contact, conductive objects equalize their individual electrical potentials to prevent sparking. Grounding is connecting a conductive object (e. g. , tanks, totes) to the earth to dissipate electricity from accumulated static, lightning strikes, and equipment faults into the ground, away from employees and equipment Eliminate flammable mixtures where static discharges may occur: • Too rich – flammable vapor concentration above the UFL • Too Lean- flammable vapor concentration below the LFL • Inert- oxygen content reduced below 8% 6

Electrostatic Hazards 1. Static Accumulation: High voltage, Low current • Created in piping and

Electrostatic Hazards 1. Static Accumulation: High voltage, Low current • Created in piping and tanks by flow of “static accumulator” products • Flow of product creates opposite charge in liquid and tank, hose or piping • Three stages : 1. Separation 2. Accumulation 3. Discharge 2. Galvanic Cell: Low voltage, high current • Created between ship and shore from steels, anodes and non-ferrous materials in salt or brackish water • Stray currents from cathodic protection systems on ships and docks • Ship and dock become a large battery • Low resistance, high current • Potential for incendive spark in flammable atmosphere 7

Static Accumulation – High Voltage / Low Current Charge accumulates due to movement of

Static Accumulation – High Voltage / Low Current Charge accumulates due to movement of liquid or vapor in pipe Voltage difference can result in incendive arc when connecting/disconnecting Insulation breakdown Different cause and different solution than Galvanic Cell 8

Galvanic Cell - Low Voltage, High Current Metal loading arm or low resistance connection

Galvanic Cell - Low Voltage, High Current Metal loading arm or low resistance connection between ship and shore Large currents can flow in electrically conducting pipework and flexible hose systems between the ship and shore High amperage current can develop and release an incendive spark when hoses are disconnected Voltage difference between ship and dock can cause electrical flow through hose or hard arm One volt difference between ship and shore can permit 30 – 40 amp current flows Prevention: • Insulation flange • Electrically discontinuous hose between ship and shore 9

Prevention of Electrostatic Hazard on Ships Basic Principles • Bond all metal objects together,

Prevention of Electrostatic Hazard on Ships Basic Principles • Bond all metal objects together, eliminating risk of discharge between objects • Ensure that all components in the cargo handling system are at the same electrical potential • In the case of tank vessels, grounding (or earthing) is effectively accomplished by bonding to the hull, which is naturally earthed through the water • Equipment should be designed to facilitate bonding and to avoid the insulation of any conducting metal 10

Cargo System Bonding Build-up of static electricity resulting from the flow of liquids/gases/vapors can

Cargo System Bonding Build-up of static electricity resulting from the flow of liquids/gases/vapors can be avoided if the resistance between the cargo tanks/process plant/piping systems and the hull of the ship is not greater than 106 ohm [МΩ, 1, 000 ohms, 1 megohm] 1 МΩ resistance will be readily achieved without bonding straps where cargo tanks/process plant/piping systems are directly welded or bolted to the hull of the ship Bonding straps are required for cargo tanks/process plant/piping systems which are not permanently connected to the hull of the ship Checks should be made on the resistance to the hull of the ship during construction of the ship and at subsequent major surveys, supplemented by visual inspection during annual surveys. 11

Insulation Flange R > 10, 000 Ω new, > 1, 000 Ω in service

Insulation Flange R > 10, 000 Ω new, > 1, 000 Ω in service Divides the cargo transfer system into electrically isolated halves Provides sufficient resistance to reduce high current flow due to voltage difference, but allows dissipation of static charge across the flange 12

Insulation Flange Location Steel Berths Insulation Flange installed at either point 1 or point

Insulation Flange Location Steel Berths Insulation Flange installed at either point 1 or point 2 Or Use on section of non-conductive hose for each transfer line Bond piping to berth loading platform Ground Concrete or Wooden Berths Insulation flange installed at loading arm riser connection (from API RP 2003) 13

Discontinuous Hose Isolation from ship shore potential difference can also be achieved by inserting

Discontinuous Hose Isolation from ship shore potential difference can also be achieved by inserting one length only of non-conducting hose without internal bonding. Electrically discontinuous hose should have a resistance of not less than 25, 000 ohms measured from end flange to end flange The insertion of such a resistance completely blocks the flow of stray current through the loading arm or the hose string At the same time, the whole system remains earthed, either to the ship or to the shore. 14

Lightning Ship or barge can be considered to be protected against damage from direct-stroke

Lightning Ship or barge can be considered to be protected against damage from direct-stroke lightning if the masts and other projections are adequately grounded to the hull Indirect: Abrupt change in the electrical field caused by lightning can cause secondary sparking at equipment that is relatively remote from the direct stroke • Insulated metallic objects can become charged by induction • Nearby lightning strike causes sudden release of charge to ground • Spark can ignite flammable mixture Most terminals will have a policy for suspending loading / discharge if lightning is nearby • Suspend cargo transfer/tank cleaning / gas freeing while lightning is in the vicinity, regardless of whether tanks are inerted • Close all tank openings and vent valves 15

Conclusions Prevention of electrostatic hazard on ships is well documented and consistent but precautions

Conclusions Prevention of electrostatic hazard on ships is well documented and consistent but precautions and safeguards are not always well understood or implemented • Bond cargo systems and metal objects to the hull, including metallic components of equipment used in cargo operations (R< 1 МΩ) • Ship / shore hose couplings (except for insulation flange) • Metallic connection between the conductors • Remove loose conductive objects that can’t be bonded • Avoid charge separation: • Limiting filling rates 1 m/s max velocity • Avoid splash filling, loading over the top or generating mists • Particles and droplets from nozzles • Isolation at the ship / shore interface (Terminals) • Insulation Flange with resistance not less than 1, 000 ohms • Discontinuous hose- one length only without internal bonding, resistance not less than 25, 000 ohms • Atmosphere Control - avoid flammable atmospheres 16

Standards, References and Available Literature 1) API RECOMMENDED PRACTICE 2003, Protection Against Ignitions Arising

Standards, References and Available Literature 1) API RECOMMENDED PRACTICE 2003, Protection Against Ignitions Arising Out of Static, Lightning, and Stray Currents, SEVENTH EDITION, JANUARY 2008 2) SIGTTO Publication (2014)A Justification into the Use of Insulation Flanges (and Electrically Discontinuous Hoses) at the Ship/Shore and Ship/Ship Interface 3) ISGOTT 5 th Edition 4) ICS Tanker Safety Guide 4 th Edition 2014 5) STS Transfer Guide 1 st Ed 2013, 6) NFPA 77: Recommended Practice on Static Electricity, 2014 Edition 7) IEC 60079 -10 -1: 2008 Explosive atmospheres - Part 10 -1: Classification of areas - Explosive gas atmospheres 8) Britton, Lawrence G, Avoiding Static Ignition in Chemical Operations, AIChem. E 1999 9) Occupational Safety and Health Administration’s (OSHA) Flammable and Combustible Liquids standard (29 CFR 1910. 106) 10)CENELEC: Safety of machinery Guidance and recommendations for the avoidance of hazards due to static electricity 17

End of Section Questions? 18

End of Section Questions? 18