Static Electricity Safety Talk 1 Safety Talk Objectives Upon completion of this safety talk, the worker will: • Know why the topic is important • Know what conditions promote the build-up of static electricity • Know and review the number of actual explosions and fires that have been caused by static electricity • Know what steps to take to prevent the build-up of static electricity Meeting preparation Pre-planning. Supervisors are encouraged to review the BP Oil Key Safety Topic entitled, ‘Successful Group Meetings’ before delivering this or any safety talk. Safety Talk 1

Static electricity Objectives Why discuss static Past Incidents Specific considerations ‘Lessons Learned’ Static electricity (Slide 2) Upon completion of this safety talk, the worker will: • Know why the topic is important • Know what conditions promote the build-up of static electricity

Objectives Understand the importance Know what causes static Review past incidents Learn prevention Objectives (Slide 3) • Know and review the number of actual explosions and fires that have been caused by static electricity • Presenter should assemble information on case histories involving static from local sources, with relevance to local processes • Know what steps to take to prevent the build-up of static electricity

A static spark may jump from the end of a finger to a metal switchplate after one has walked across a carpet. (Slide 4) Simple example of static electricity generation.

Why discuss static ? Hazard created by ‘spark’ Walking on carpet Lightning Why discuss static ? (Slide 5) The principal hazard of static electricity is a spark discharge which can ignite a flammable atmosphere resulting in fire and / or explosion. We are all familiar with the static spark that may jump from the end of a finger to a metal switchplate after one has walked across a carpet. Lightning is a dramatic example of static electricity discharge.

Charge separation in a pipe Charge separation in a pipe (Slide 6) Static electricity is generated wherever surfaces separate. In the example above, the liquid is positively charged and the pipe negatively charged. While the liquid is in the pipe there is no danger, but when it passes into a tank or vessel the charge remains in the liquid. If the liquid is highly conductive, eg. water or crude oil, the charge rapidly dissipates to earth through the metal shell, assuming it is effectively earthed or grounded. Where the liquid is not conductive, such as refined naphthas, kerosenes and gas oils, the charge will remain in the body of the liquid for a longer time and can result in an incentive spark passing between the liquid surface to an earthed component, eg. fill pipe, sample thief, gauging bob.

Past Incidents Truck loading ‘Switch’ loading Steaming equipment Plastic sample bottles Drum filling Lightning / floating roof tanks Past incidents (Slide 7) Most of the past incidents reported have occurred during truck loading operations and many are associated with ‘switch’ loading. Refined flammable liquids – such as gasoline, kerosene, jet fuels, fuel oils and similar products become charged with static electricity from pumping, flow through pipes, filtering, splash filling or by water settling through them. ‘Switch loading’ = the loading of a product having a high flash point eg. diesel fuel, after a load of product having a low flash point eg. gasoline. Fires and explosions as a result of a static discharge have also occurred while steaming out equipment, using plastic sample bottles and during drum filling operations. Lightning has been cause of many rim seal fires on floating roof tanks. Over 40 fires and explosions have been reported in the Refineries Quarterly Safety Bulletin over 20 years from ignition of flammable atmospheres caused by static discharge or lightening (33 from static, 10 from lightening). • 13 incidents were attributed to high flow rates • 9 incidents were attributed to inadequate ground and bonding of piping & truck • 7 were due to inadequate watering / flushing between products (switch loading) • 4 were caused from splash filling Actual case histories are available from your Business Safety Supervisor.

Generation of static electricity occurs from oil flow through filters, pumps, pipe and fittings and by splashing and spraying. (Slide 8) Diagram showing how static electricity can be built up in a pump circuit. The faster the flow, the greater the static build up. Anti-static additives are used to allow static electricity to be safely dispersed without creating incendive sparks, eg. anti-static additive is added to jet fuel which is loaded onto aircraft at high flow rates.

Specific considerations Clothing Bottom loading Specific considerations (Slide 9) Clothing Under favourable conditions, many fabrics can generate static electricity. This can occur when the fabrics are brought into contact with other materials and then separated, or when they are rubbed on various substances. Most synthetic fabrics, (Nylon, Orlon, Dacron and Rayon) are more active generators than are natural fabrics. Both rubber and leather-soled shoes generate static when the wearer walks on dry carpeting or other nonconductive surfaces during periods of low humidity. Such potentialities should be recognised and prudence exercised on any occasion when flammable vapors are present. It is important to note, however, that clothing must not be removed in a potentially flammable atmosphere. In a normal petroleum industry operations, special measures to ground personnel or to provide antistatic clothing are not necessary. Even after recent incidents attributed to clothing were reviewed, the position of this recommended practice remains unchanged. For additional information, refer to API 2003. Bottom loading – see 1/10

Loading and unloading of tank vehicles through closed connections Loading & unloading of tank vehicles (Slide 10) Bottom loading At the majority of BP terminals, tank trucks are bottom filled. As part of this instrumentation, a ‘ground’ proving system in incorporated which is interlocked to the pump circuit. This ensures that only when a good ‘ground’ is made, is the pump allowed to operate to fill the truck compartment with product. This reduces possibility of electrostatic hazards. Such important safety devices must not be bypassed unless authorised by line management. However, in the initial stages of bottom loading, upward spraying of the product can increase charge generation and should be prevented by reducing the filling velocity or by using spray deflectors or other devices. Low-vapor pressure products like gas oil can form an ignitable mist if bottom-loading inlets in tanks are not designed to avoid spraying. Bottom-loading rates should comply with flow restrictions described in API 2003. Bottom loading may result in higher liquid surface static charges than would top loading, because the downspout acts a conductive path to help relax a charge. With bottom loading, it is especially important that spark promoters (for example, gauging rods and other metallic conductors) be extended to the tank bottom, as recommended in API 2003.

(Slide 11) ‘Lessons learned’ / prevention Don’t start to load a high flash point product such as kerosene until you have drained the truck and made sure that the previous load was a product having a high flash point. If a low flash point product such as a gasoline was in the previous load, do whatever is required to make the truck safe to receive the product having a high flash point. Specific top loading matters Don’t keep a top-entering loading spout high. If you do, the splash and spray will help build up a static charge, and a spark can discharge between the rising liquid surface and the end of the spout may occur. Don’t withdraw a loading spout from the tank bottom immediately after loading. Wait at least a minute for surface charge to relax. Otherwise, there may be a spark discharge from the liquid surface to the loading spout.

Sampling Sampling (Slide 12) General matters Static electricity discharge and flammable atmosphere = danger of fire or explosion. • Precautions a) prevent static build-up OR b) eliminate flammable atmosphere • Earthing and Bonding prevent static charge build-up. Make sure the truck is always grounded before commencing loading. Only use metal sample containers electrically bonded to the tank truck outlet before taking bottom samples • Don’t sample by dipping through the top opening during loading or immediately after loading. Wait at least a minute for surface charge to relax. Spark discharges between the liquid surface and dipper or thief, or between the charged dipper or thief and tank rim, have occurred because someone was in a hurry to obtain a sample • Operating techniques minimise charge build-up and assist charge dissipation. Follow specified loading rates, do not bypass safety devices, do not modify operating practices unless authorised by line management • Flammable atmospheres can be eliminated by: a) purging b) inerting c) eliminating vapour space Remember you cannot see a static charge being built up until it is too late and a spark is produced. Observe your terminal operations procedures manual and report all incidents of static electricity.

Prevention Earthing and bonding Allow relaxation time – >1 minute before sampling road tankers – >30 minutes before sampling / gauging storage tanks Do not exceed specified loading rates Do not bypass safety devices Eliminate flammable atmospheres by: – purging – inerting – eliminating vapour space Prevention (Slide 13) These are simple, but effective safety measures. For precautions during sampling/gauging storage tanks, see Safety Talk No. 2 (Slide 2/13).