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Improving Lightning Safety forUpstream and Downstream Oil& Gas Operations

Lightning has undoubtedly in one or moreoccurrences have caused damages andlosses to upstream operations (offshorerigs, vessels, etc...) or/and downstream op-

erations (onshore gas terminal, petroleum storagetanks, floating roof tanks, etc...).

According to a review of petroleum storage tankfires between 1951 and 2003, the number of tankfires reported in the worldwide media is in therange of 15 to 20 fires per year. The extent of the tankfire incidents varies considerably, ranging from arim seal fire to multiple, simultaneous full tankfires. Of the 480 tank fire incidents reported in themedia, about one-third has been attributed to light-ning. Another study, sponsored by 16 oil industrycompanies, found that 52 of 55 rim seal fires were

caused by lightning, and concluded that “lightningis the most common source of ignition.”In Malaysia, 8 numbers of storage tanks were de-

stroyed in Pasir Gudang in April 2006 due to light-ning related fires.

In the summer of 2008, a floating roof tank in KansasCity was ignited and burned for three days. Duringthe summer of 2007, a floating roof tank in Wynnewood,Oklahoma, was also ignited. In both cases, lightningwas the cause of ignition. In both cases, in addition tothe huge cost of lost product, there were also numer-ous large, incalculable costs, including damage to thephysical plant; interruption of customer service; envi-

ronmental harm; firefighting, cleanup and rebuildingcosts; EPA, OSHA and regulatory fines and increasedoversight; loss of community goodwill, etc.

For offshore facility, being one of the tall isolated

objects in the middle of the ocean, it bears high risk of  being struck by lightning. Any direct strikes to flam-mable materials onboard the offshore facility can causedevastating accidents. These accidents can endangerthe safety of personnel onboard. Any secondary effectof lightning can cause loss of function and productiondue to malfunction of critical equipments onboard.

Problems Associated with LightningThe problems associated with lightning are di-

vided into 2 main problems- Direct Strikes and Sec-ondary Effects of Lightning. Both Upstream and

Downstream facilities experience both types of prob-lems. Some facilities may experience reoccurrenceof similar problems while others may claim thatthey do not have such problems before. Regardlessof whether the facilities have experienced lightningrelated problems or not, the fact is lightning risk isreal and safety of personnel is at stake.

Direct StrikesDamages caused by Direct Strikes are easy to be

recognized- there will be visible burn marks onequipments/structures/personnel struck by lightning.The affected equipments are normally beyond repair.

afety

While safety is a priority in the Oil & Gas industry, unfortunately, it is also one of the most 

vulnerable industry when comes to lightning related dangers. Despite the known problems and dangers associated to lightning strikes and the increasing secondary effects it causes to critical oil and gas facilities, not many operators truly understand what lightning is all about, thus not being able to implement preventive measures to improve lightning safety in their facilities.This paper addresses the problems associated to lightning and the methods to safeguard the reliability of Upstream and Downstream Oil & Gas operations by improving lightning safety through HSE programs, direct strike protection, surge protection, bonding and grounding.

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As for structures, depending on the level of the damagecaused by lightning, some can be repaired and someneeds to be replaced but whatever is the remedy, theoperation down time is definitely affected and this canmean loss of production. When struck by lightning, thepersonnel involved can never survive a direct strikeand the company loses one of its important assets.

Secondary Effects of LightningThe Secondary effects of lightning are described

as follows:• Electromagnetic Pulse (EMP) Effect affecting

electronics components inside equipments-equipments get damaged overtime due to fail-ures of components inside the equipments caused

 by EMP effect.• Atmospheric Transients affecting elevated objects

(i.e. cranes, towers, etc..). For example, load cellsand control cards on cranes are normally affected by this type of transients.

• Earth Current Transients affecting cables (i.e datalines, signal lines, control lines, power lines, etc..).One of the common problem for offshore facilitiesis that PLC modules are easily affected/damaged by this type of transient. For onshore facilities,common problems are the temperature or/andflow sensor. These sensors either malfunction orgive out wrong signals/readings when there are

lightning activities.• Bound Charge and resulting Secondary Arc affect-

ing petroleum storage tanks- both fixed roof andfloating roof. Bound Charge is defined by API ascharges momentarily bounded in tanks and seekto be discharged during a lightning strike nearby.In the process of being discharged through theconductive tank shell to the point of lightningtermination, should there be any flammable va-pour between the gaps of the tank shell and theproduct, arcing will happen and can cause fire. Theworst thing that could happen will be explosion.

Improving Lightning Safety for UpstreamFacilities

The upstream facilities include offshore rigs andvessels. Many of the geographical locations wherethese facilities are situated are either in the middle of the ocean or in the middle of the dessert, makingthem one of the higher isolated objects- vulnerableto high risk of direct lightning strikes. Consideringthe operational area, the types of lightning relateddamage and the overall cost associated with a loss-time event for upstream facilities, it is recommendedthat the following measures be considered to im-

prove lightning safety for upstream facilities:• the implementation of a Direct Strike Preven-

tion Method. Traditional primary protectionsystems are designed to attract and collect light-ning strikes in order to safely direct the light-ning’s energy to ground. However, the collectionof lightning strikes increases the exposure of secondary lightning effects to the Rig/Vessel’selectric and electronic systems. The result isincreased operation down time and maintenancecost due to damaged equipment.Lightning Strike Prevention technology is rec-ommended as opposed to lightning collectionsystems to minimize the risk of exposure to allthe harmful effects from lightning strikes.

• Surge Protection devices to be implemented forall possible entries of transients via AC or DCpower, signal, data, control and coaxial lines/cables. The AC surge protection devices should be specified with proper surge ratings depend-ing on application. For other types of surgeprotector- Data Line/Network Protector andCoaxial Protector, they should be installed asclose as possible to the equipment ends.

• Bonding Maintenance Program. The sea is natu-rally a good conductor for upstream facilities.Therefore grounding is not an issue. The concernlies on proper bonding practice amongst struc-

tures on the offshore rigs and vessel facility. Mostof the structures are bonded together by means of welding and mechanical joints. For those withmechanical joints, it is crucial to ensure that the joints are protected against the highly corrosiveenvironment. Any joints that are corroded willgive high resistance path and is not good for bonding purposes. Bonding cables used shouldalso be ensured to be as short and as straight aspossible to provide low resistance path to ground(the sea). A bonding maintenance program put inplace will help to address the bonding issue.

Improving Lightning Safety forDownstream Facilities

Two of the most lightning affected downstreamsectors are oil refineries and petrochemical plants.

Oil RefineriesIn oil refineries, fires involving petroleum stor-

age tanks are quite common. Almost one-third of all tank fires are caused by lightning. In improv-ing lightning safety to oil refineries, the followingmeasures can be taken in terms of:

• the implementation of a Direct Strike Prevention

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Method. Metal tanks are supposed to be self-protecting against lightning with certain thick-ness requirement fulfilled under NFPA 780 andwith proper electrical bonding. However, theBound Charge and resulting Secondary Arc caused by lightning affecting petroleum storage tanks isreal. Lightning Strike Prevention technology isrecommended to reduce charge build up on tanksto be protected and to minimize the risk of expo-sure to direct and secondary harmful effects of lightning strikes.

• Surge Protection Devices can be implemented insections or areas that are critical to the oil refin-ery’s operation. The possible entries of transientsfor oil refineries are similar with upstream facility

such as via AC or DC power, signal, data, controland coaxial lines/cables. The AC surge protectiondevices should be specified with proper surgeratings depending on IEEE Category A, B or Clocations where they are to be installed. For othertypes of surge protector- Data Line/Network Pro-tector and Coaxial Protector, they should be in-stalled as close as possible to the equipment ends.

• Bonding. One of the major challenges for oil refin-eries when faced with lightning related fires is thevulnerability of Floating roof tanks (FRT’s) tolightning. In improving lightning safety to float-ing roof tanks, it is crucial that the floating roof 

 be electrically bonded to the tank shell for the roof to be at the same electrical potential as the tankshell. If the roof and shell are not at the samepotential, and if the potential difference betweenthe two becomes great enough, an arc will form between the two surfaces and can cause rim firesand worst case-tank explosions since flammablevapours may be present in imperfect seals.Due to this vulnerability of FRT’s, the AmericanPetroleum Institute (API) created a technical com-mittee to evaluate this situation and to recom-mend solutions. The API has issued a document

entitled API RP 545, Recommended Practice for Light-ning Protection of Above Ground Storage Tanks for Flammable or Combustible Liquids. Two of the keyfindings from API test program were:(1) when lightning current passes through

shunts at the roof-shell interface, it willresult in arcing under all conditions

(2) it is the slow component of the lightning strokewhich ignites flammable vapours.Therefore, when the slow component of alightning stroke passes through any roof-shellinterface, if flammable vapours are present,they will likely be ignited.

As a result, API RP 545 recommends three majormodifications to FRT’s:1. Install submerged shunts between the roof 

and shell every 3 meters around the roof perimeter, and remove any existing above-seal shunts.

2. Electrically insulate all seal assembly compo-nents (including springs, scissor assemblies,seal membranes, etc.), and all gauge andguide poles, from the tank roof.

3. Install bypass conductors between the roof and shell no more than every 30 meters aroundthe tank circumference. These bypass conduc-tors should be as short as possible and evenlyspaced around the roof perimeter.

Modifications #1 and #2 both require substan-tial design changes and overhauling of newand existing tank designs. Modifications #1and #3 are methods to bond the roof and shellon FRT’s. Modification #3, installation of  bypass conductors, is relatively easy andinexpensive to implement when compared tothe other modifications, and can be imple-mented immediately.One of these bypass conductors available inthe market is known as the RetractableGrounding Assembly (RGA). The RGA is aretractable bypass conductor which will al-

ways be as short as possible, and offersubstantially less impedance, regardless of FRT roof position and especially when theFRT roof is high. This keeps the tank shell andthe floating roof bonded all the time and at thesame electrical potential thereby solving theproblems of arcing at the shunts and otherroof-shell interfaces caused by the slow com-ponents of the lightning stroke.

• Grounding. Grounding for Oil Refineriesshould be implemented depending on thefollowing factor:

1) Type of soil and soil resistivity2) The presence of cathodic protection3) Requirement of User and Standards on the

acceptable value of grounding resistance4) Corrosive environment

To cater to the above factors, it is important to have agrounding system that can achieve low impedancepath all the time. With most tank farms having cathodicprotection to protect the tanks against corrosion, it isalso crucial to ensure that the grounding system pro-vided does not get sacrificed/corroded easily. One of the solution is to use a tinned copper rod instead of apure bare copper rod. This copper rod if filled with

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chemical salts can help to provide a consistent groundresistance reading throughout any season. A biggerdiameter size of the ground electrode will also help inenhancing the surface contact of soil to the groundelectrode and increase the conductivity of the soil. Thiswill help facilitate low impedance path for lightningcurrent to be discharged when the tank is struck di-rectly or indirectly. One of this type of ground electrodewhich is available in the market is called the Chem-Rod.

Petrochemical PlantsSimilar to oil refineries tanks, many structures in

Petrochemical Plants are metal and are supposed to beself-protecting against direct strikes. Nevertheless,common problems such as flare stacks igniting during

thunderstorm and flow sensors/temperature sensorsregistering wrong readings or malfunction are ram-pant and can cause safety concerns.

In improving the lightning safety for PetrochemicalPlants, similar strategies in terms of Direct Strike Pre-vention, Surge Protection and Grounding as highlightedfor the implementation at oil refineries. For bonding of new petrochemical plants, during construction period,it is recommended to use exothermic welding for per-manent good electrical bonding. This type of joints canensure no corrosion or oxidization happening betweenthe plant structures and earthing cables.

ConclusionLightning related damages and threat for Oil & Gas

operations are real. The efforts in improving lightningsafety for upstream and downstream facilities do notdepend only on certain individuals but needs theactive participation of all employees and manage-ment. These efforts can be summarized as follows:

• Implementation of Total Lightning Protection Sys-tem which consists of Direct Strike Protection,Surge Protection, Bonding and Grounding

• Active implementation of HSE Program relatedto Lightning Safety- be it personal safety against

danger of lightning (i.e. touch potential, steppotential).• Establishment of Standard Operating Procedures

at workplace during thunderstorm (i.e. establish-ing the red zone and green zone of where is safe towork and where is not safe to work should person-nel be caught in the facility during thunderstorm)

• Awareness that preventive measures are moreimportant than stop gap measures. Most of thetime, reactive stop gap measures are carried outwhen there have been lightning related problems.Not many facilities will take proactive preventivemeasures to prevent these lightning related prob-

lems from happening in the first place.• Constant upgrading of knowledge and training of 

personnel to be aware of latest lightning protec-tion technologies and to be open about applyingthese technologies in their facilities to help reducelightning related problems.

References• API RP 545: Recommended Practice for Lightning Protec-

tion of Above Ground Storage Tanks for Flammable or

Combustible Liquids, 2009• Drabkin M.M, Grosser A, “Lightning Protection of Flamma-

 ble Storage Facilities”, Proceedings of International Confer-ence on Grounding and Earthing and 2nd InternationalConference on Lightning Physics and Effects

• Drabkin M.M, Howard L.B, “Retractable Grounding Assem- bly Improves Lightning Protection Of Floating Roof Tanks”,Proceedings of International Conference on Grounding andEarthing and 2nd International Conference on LightningPhysics and Effects, Brazil, November, 2006.

• NFPA 780 Standard for the Installation of the Lightning

Protection Systems, 2004 Edition• BS EN 62305-1-2006 Protection Against Lightning• Joe Lanzoni, “Improving Lightning Safety of Petroleum

Storage Tanks”, 2009

This publication thanks Ms. Ong Lai Mun for pro-viding this paper, which was presented at the RAMS

 Asia 2012 C&E. Ms. Ong has over 7 years of experi-ence in conducting audit services and undertakingprojects related to lightning protection, surge protec-tion and grounding. The countries that she has experi-ence implementing these projects include Malaysia,Singapore, Indonesia, Brunei, Thailand, Korea andVietnam for clients in the industry of Oil & Gas (i.e.PETRONAS, Shell, Mitsui Chemicals, ExxonMobill,SapuraAcergy, etc..), Telecommunication (i.e. Ericsson,Celcom, MobileOne, etc..), Broadband (Smart Digital, Jaring, Measat, etc…), Themepark (Universal StudiosSingapore, Resorts World at Sentosa). Prior to work-

ing with Hitachi Critical Facilities Protection, shepursued her Master in Electrical Engineering inUniversiti Teknologi Malaysia, specializing in theresearch of lightning protection. She has publishedtechnical papers for international conferences such as ICLP 2012 and 2006 (International Conference onLightning Protection), SIPDA 2005 (InternationalSymposium on Lightning Protection), IPEC 2005 (In-ternational Power Engineering Conference) and AEESEAP 2004 (Association of Engineering Educa-tion in South East Asia and the Pacific Conference).

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