Arc flash concerns in the oil and gas industry
In just about any oil and gas refinement process, whether in an upstream, downstream, or midstream facility, electricity is a vital component that is necessary for production.
Despite all of the advances in electrical distribution and control, however, anyone working on or near live electrical equipment knows that there is one obvious danger that they must protect themselves against – electrocution.
Electrocution is one of the leading causes of workplace fatalities around the world. A 2010 report from the International Oil & Gas Producers Association found that 16.1 percent of all fatalities at oil fields were caused by an electrical accident, explosion, or burn. Most electrical accidents are not the result of direct electric shocks, but instead result from a particularly hazardous type of shorting fault, called an arc fault or flash, that can occur throughout oil and gas facilities.
Beware of the arc
Arc flash is the sudden release of electrical energy through the air when insulation or air separation causes a high voltage gap between conductors, leading to a breakdown in safe conduction of electricity. Put more simply, an arc flash accident happens when a large electrical current passes through ionised air and gases. Arc flashes can result from a variety of causes:
• A worker being in close proximity to a high amp source with a conductive object can cause the electricity to flash over
• Human error, including dropped tools, accidental contact with electrical systems, and improper work procedures
• Equipment failure due to use of substandard parts, improper installation, or even normal wear and tear
• Breaks or gaps in insulation
• Dust, corrosion, or other impurities on the surface of the conductor
An arc flash gives off thermal radiation (heat) and bright, intense light that can cause burns. Arc flash temperatures have been recorded as high as 19,000 degrees Celsius (C) or 35,000 degrees Fahrenheit (F), which is four times hotter than the surface of the sun.
High voltage arcs can also produce considerable pressure waves that move up to 1,120 kilometres per hour (700 miles per hour) by rapidly heating the air and creating a blast. This pressure burst is forceful enough to throw a worker across a room, as well as send molten metal droplets from melted copper and aluminium electrical components great distances at extremely high velocities. This can result in several types of injuries, such as burns, respiratory damage, hearing damage, skin penetration from debris, and eye and face injuries. To put the power of arc flash into perspective, take a look at the following comparisons:
• Hot summer day: 37.7° C/100° F
• Surface of the sun: 4,730° C/8,540° F
• Arc at arc terminals: 19,720° C/35,540° F
It has been estimated that up to 77% of all on-the-job electrical injuries are caused by arc flash incidents, according to a ten year study involving more than 120,000 employees, performed by Electricite de France.
With the additional presence of flammable vapours, volatile liquids, and explosive gases in the oil and gas industry, arc flash has the potential to trigger a catastrophic event. The cost of one arc flash incident can reach millions of dollars after accounting for damaged equipment or infrastructure and lost production time. This cost can reach up to $15 million when workers’ compensation and increased healthcare costs and insurance premiums are included, according to an Electric Power Research Institute (EPRI) study.
The potential for such costly accidents means that the issue of safety is a high priority in the oil and gas industry – especially with growing energy demands in areas like the Middle East, China, and Brazil.
Growing industry, growing concern
The Middle East continues to house a large number of the world’s oil and gas extraction and production related facilities. According to a 2012 report from the US Energy Information Administration, the Middle East leads the global crude oil and condensate production in the world, having produced 24.1 million b/d (barrels per day) of crude oil, which is almost twice as much as the next highest region. Additionally, according to the International Energy Agency’s most recent Oil Market Report, global oil demand is forecast to average 92 million b/d in 2014, up from 90.9 million b/d in 2013, therefore suggesting that daily production rates in the Middle East will increase further.
Last November, 2013, McDermott International won an Engineering, Procurement, Construction, and Installation (EPCI) contract valued at around $200 million for an offshore oil extraction project in the Middle East, the scope of which includes the fabrication, transportation, and installation of two production deck modules and ten observation platforms, two subsea pipeline installations, three submarine power cables, and two fibre optic cables. This is just one of many examples where countries in the Middle East have seen massive development in the oil and gas industry.
Safety procedures and regulations
In 2014 and beyond, oil and gas facilities in the Middle East will need to ensure that along with increased production comes appropriate safety training. As mentioned above, arc flash is a serious problem in this industry, and although the danger of arc flashes has always been present, a push for increased production and speed can mean that workers are less careful about following safe practises, bringing arc flash awareness to the forefront.
To ensure safety and compliance measures are being taken throughout a workplace, it is critical that both upper management and employees know how to identify arc flash hazards in their facilities, utilise safe work practises, and understand labels and other awareness aids. It is critical that everyone stays up to date on standards and reinforces safe behaviour.
This requires training and education for workers to identify the risks, as well as an arc flash mitigation plan in place both for existing equipment and new projects, with initiatives such as:
• Creating and enforcing a complete arc flash strategy
• Conducting ongoing employee training
• Providing the proper arc flash personal protective equipment for the level of risk
• Identifying and evaluating arc flash potential throughout a location
• Calculating incident energy exposure and arc flash boundaries
• Utilising warning labels to specify arc flash hazard levels
Workplace standards for safety and health are very different between countries, economic sectors, and social groups. For the purpose of this article, the standards and best practises of the United States and the United Kingdom are the primary references.
Currently, there are no definite standards for personal protective equipment or practises in the Middle East region with regard to arc flash protection. The International Labour Organization is working with countries in this region to develop a stronger presence of ISO standards.
Additionally, the American Society of Safety Engineers (ASSE) has a chapter in the Middle East that works to bring a higher standard of safety to the region. The ASSE is one of the oldest and largest professional safety organisations in the world, with 33,000 members, 12 divisions, and 148 chapters in the United States and abroad. The Middle East Chapter was the first chapter established outside of the United States.
In the United States, there are several regulations that apply to personnel working with energised electrical equipment under the Occupational Safety and Health Administration (OSHA) and the National Fire Protection Association (NFPA).
OSHA cites and fines employers for failure to protect employees from the dangers of arc flash. In some cases, corporations face potential fines of $600,000 per offence, with individuals facing potential fines of $27,500, or 12 months in jail.
OSHA refers employers to the 2012 edition of the NFPA 70E standard for guidelines on best practises to protect employees. Here are the four main regulations relating to arc flash in the United States
• OSHA 29 CFR-1910, Subpart S provides the legal requirement for employers to guard against arc flash hazards. It sets general requirements for safe work practises, PPE, and hazard analysis
• NFPA 70, called the National Electrical Code (NEC), provides a requirement for arc flash labels
• NFPA 70E, ‘Standard for Electrical Safety in the Workplace’, outlines the specific procedures and practises to be followed for OSHA compliance and safety when working on live equipment
• IEEE 1584, ‘Guide to Performing Arc Flash Calculations’, provides the formulas necessary for analysing arc flash hazards NFPA 70E is the leading internationally recognised safety standard for arc flash prevention and protection. It covers shock hazards in a similar way to European codes and standards, but with an additional requirement – it requires a risk assessment for arc flash hazard. This means that before work can be carried out near energised conductors, the following must be done:
• There must be a known hazard. A thorough arc flash hazard analysis must be conducted to determine the amount of thermal energy that could be generated in an arc flash incident. This establishes the shock and protection boundary around the potential source
• Measures must be taken to reduce risk. Warning labels on the equipment must identify the hazard and summarise this information
• The appropriate personal protective equipment (PPE) must be worn. Arc-rated protective clothing and other appropriate PPE must be worn for two main reasons. Firstly, when risk cannot be reduced through other means, and secondly when employees cross the protection boundary while they work on or near exposed ‘live’ parts.
It is important to remember that NFPA 70E does not protect personnel against the effects of arc blast.
The most effective way to eliminate the risk of electrical shock or arc flash is to simply de-energise the equipment, and NFPA 70E has some important safety recommendations on how to establish an ‘electrically safe work condition’ before working on a circuit:
• Identify all power sources
• Interrupt the load and disconnect power
• Visually verify the disconnect has opened the circuit
• Lock out and tag the circuit
• Perform voltage testing
• Ground all power conductors
In truth, there is no way to completely eliminate arc flash accidents, but the risk can be further mitigated by providing those working on electrical equipment with suitable personal protective equipment, as covered above and below.
Personal Protective Equipment
Following the relevant safety guidelines and using personal protective equipment (PPE) could mean the difference between life or death for a worker involved in an arc flash or arc blast incident. In the United States, OSHA requires workers who work around electrical hazards to have head-to-toe protection.
All of the steps listed above regarding NFPA 70E require the use of appropriate PPE for shock and arc flash protection. This includes safety glasses, voltage rated gloves, flame resistant neck protection, arc-rated face shields, flash suits with hoods, and hearing protection.
Also, workers are outfitted with arc rated work suits, insulated rubber gloves (preferably with leather protectors), and insulated leather footwear. All materials must be metal-free to avoid the possibility of arc flash, whereby a fault creates electrical contact with the worker.
It is also important to select PPE appropriate for the task; for example, the use of restrictive or excessive PPE on a worker who does not need this category of protection can be hazardous, as an overheating worker struggling with poor visibility and restricted movement is more likely to have an accident. Remember that the use of PPE is a worker protection measure – it does not control the problem at the source.
Personal protective equipment for arc flash includes the following:
1. Gloves. These are a crucial piece of PPE for electrical workers, combining high dielectric and physical strength with flexibility and durability. Depending on the hazard level of work, there are several kinds of gloves to choose from, such as heavy duty leather gloves, rubber insulating gloves, or a combination of both.
2. Clothing. Employees must wear protective clothing that is deemed appropriate based on the energy and risk associated with the task being performed. Other PPE may be required for specific tasks with various weight fabrics, which can be provided as a shirt and trousers, as coveralls, or as a combination of both for increased protection.
Generally, a higher degree of protection is provided by heavier weight fabrics and/or by layering combinations of one or more layers or arc rated clothing. These items are made to a suitable calorie rating to reduce the harmful energy on the body, so that any burns suffered are not life threatening.
Arc rated clothing must be worn wherever there is possible exposure to an electric arc flash above the threshold level for a second degree burn, and it should cover all ignitable clothing as well as allow for movement and visibility.
In some cases, one or more layers of arc rated clothing are worn over flammable, non-melting clothing. Used alone, non-melting, flammable clothing can provide protection at low incident energy levels. Alternatively, clothing made from acetate, nylon, polyester, acrylic, polyethylene, and rayon, in either pure or blended forms, should not be worn when working in hazardous environments
3. Headgear. Employees must wear nonconductive head protection wherever there is a danger of head injury from electric shock or burns due to contact with live parts, or from objects flying as a result of an electrical explosion. Headgear also includes nonconductive protective equipment for the face, neck, and chin. When necessary, face shields should have an arc rating suitable for the arc flash exposure, and eye protection, such as safety glasses or goggles, which should be worn under face shields or hoods.
4. Foot protection. There are two types of shoes that provide some protection from electrical shock, both of which have insulated soles: dielectric and electrical hazard rated. Dielectric overshoes are used where there is a risk of electric shock from high voltages in both dry and damp conditions. Electrical hazard footwear is usually used in low voltage and dry conditions. Insulated soles should not be used as the primary electrical protection, however.
5. Insulated tools and equipment. Employees must use insulated tools and handling equipment when working around energised electrical equipment or exposed live parts where there is potential for contact. Insulated tools should be protected from damage to the insulating material, such as being composed of impact resistant and flame retardant material.
Insulated tools should be rated appropriately for the voltages to which they may be exposed, and should also be designed and constructed for the environment and manner in which they will be used.
With the potential for serious injury or death from an arc flash accident, arc flash injury prevention is an important topic within the oil and gas industry. The hazardous environments found in oil and gas facilities mean that workers need to be especially attentive, as arc flash can cause considerable damage to equipment and serious injury to nearby workers.
The right thing for an organisation to do is to provide protective measures for workers who work with or around energised electrical equipment, to prevent injury to workers or damage to equipment due to arc flash.
The combined efforts for safety by organisations that provide standards, workplace safety initiatives, and advanced equipment design, along with employers and employees, will help to reduce and control the danger of arc flash.
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Published: 10th Apr 2014 in Health and Safety Middle East