Power plant safety

Issue 6 and Volume 109.

Preparing the troops

Power plants are much safer than they once were; however, plant employees still encounter hazards. Training, along with proper operation and maintenance procedures, are key to reducing accidents and mitigating their effects.

By Teresa Hansen, Associate Editor

In the past several decades, power plant owners and industry in general have vastly improved employee safety. Numerous organizations that hand down safety requirements and regulations have been established, creating a safer work environment. Although power plants are much safer than they once were, plant employees still encounter many hazards, and it is up to employers to implement programs and policies aimed at eliminating accidents. The Boy Scout motto “be prepared” certainly applies when it comes to power plant employee safety. Comprehensive training, detailed pre-job planning, and proper and well-maintained safety equipment are key to accident prevention, regardless of the hazard.

Among the most common hazards to power plant workers are electrical shocks and burns, boiler fires and explosions, and contact with hazardous chemicals. While these are most certainly not the only hazards encountered by power plant workers, they are definitely worth review.

Electrical Hazards

Michael Foley is an electrical safety instructor with National Technology Transfer Inc., an Englewood, Colo.-based company that provides nationwide training to utility, industrial and commercial electrical workers in the Occupational Safety and Health Administration’s (OSHA’s) and the National Fire Protection Association’s (NFPA’s) electrical safe work practices. In addition, he is president of Technical Consultants Group Ltd., an electro-forensic investigative firm based in Denver. Foley understands the perils of working around electricity, as well as the precautions that should be taken to avoid injuries and accidents. He explains that there is really not a good common system in place for reporting and recording the number and type of electrical injuries and fatalities that occur in power plants or general industry for that matter. According to Foley, many of the reported numbers are “soft” and can be misleading. “For example,” Foley says, “a worker on a platform could hit a power line, receive an electrical shock and fall from the platform, breaking an arm or leg, or worse. This accident could easily be reported and classified as a fall, even though the fall was obviously caused from an electrical shock.

“Another example could be a worker who drops a screwdriver near open-bus, energized electrical switchgear and receives a burn from a subsequent arc flash,” says Foley. “This incident might be reported as a burn, not an electrical arc-flash incident.”

Even with the potential for these incidents to be wrongly classified, the Electrical Safety Foundation International reports that an average of 133 workers die each year due to contact with power lines. In addition, most authoritative sources on electrical incidents report that approximately 400 general industry workers, including power plant workers, die each year from electrical shocks. When combined, these figures represent one or two deaths daily due to electrical incidents.

Although these numbers may not seem that large when compared to the total number of people working around electrical hazards, even one death or serious accident can be extremely costly and devastating to a company. The National Safety Council estimates that an electrocution death costs about $1 million.

This figure includes costs of lost productivity over the life of the employee, direct medical expenses and insurance premiums. Foley believes that this is only a small portion of the actual costs associated with such an accident, because it does not reflect the cost of legal liability – such as defending against lawsuits. He also points out that this figure does not represent costs associated with severe injuries, such as burns, that do not cause death. Because of the expense associated with treating serious burns, the long recovery time associated with them and the debilitating nature of burns, the costs can be much more than the National Safety Council’s $1 million estimate.

Generally, electric shocks or electrocutions are thought of as the main hazards associated with electrical work. According to Foley, however, 75 percent of all reported lost time electrical-related incidents are due to burn injuries from the arc flash. “In the past 15 to 20 years, we’ve learned that the arc flash, not the shock, causes most injuries,” Foley says. “Industry has addressed shock hazards well, but not until recently the arc flash.”

Often, the person actually working in an electrical cabinet is wearing proper protection, but others, who may be working with that person but not directly in the cabinet, are not protected at all. “An arc can reach 10 feet from the source, so it is important for anyone working near an electrical cabinet or similar electrical equipment to be protected,” Foley adds.

OSHA sets many of the electrical safety rules for general industry and for utility workers. According to Foley, OSHA’s electrical safety rules for utility workers are a little more lax than the electrical safety rules for general industry. This is because under the OSHA rules utility electrical workers are likely classified by their employer as “qualified workers.” In 29CFR 1910.269, a qualified worker is defined as: “One knowledgeable in the construction and operation of the electric power generation, transmission and distribution equipment involved, along with the associated hazards.” This category obviously includes power plant workers and electrical transmission and distribution workers routinely exposed to electrical hazards. According to Foley, OSHA’s logic is focused on the belief that electric utility workers are better trained on electricity and its potential hazards and should be more knowledgeable about electrical safety than general industry workers.

Much of OSHA’s regulation for electrical hazards defaults to NFPA’s Standard for Electrical Safety in the Workplace – NFPA Standard 70E. Under this standard, the basic requirements for general industry dictate that workers wear clothing appropriate for the level of hazard to which they are exposed. According to Foley, this means that workers exposed to energized panels, where the risk of significant arc-flash exists, must wear flame-resistant clothing. The same, however, is not required for qualified utility workers. The requirements for a qualified worker dictate that the worker wear clothing that will not worsen an electrical injury – most likely an arc-flash burn. Foley says this means the electrical workers shall not wear synthetic clothing, but the clothing doesn’t have to be flame-resistant.

Utilities and power companies can create their own safety regulations that go beyond OSHA and NFPA requirements. Foley believes they should do just that: and, most do, he adds. According to Foley, the best way to prevent accidents is for companies to conduct more frequent electrical hazard training; conduct awareness training to make sure workers understand all the hazards, including arc flash hazards, associated with the specific equipment; and most importantly, include a safety review during job preplanning. “Employees who work around electricity can easily become complacent because they’ve performed the tasks for many years. It is at this point that injuries often occur,” he says.

“Failure to recognize a hazard or its potential intensity is one of the main causes of electrical-related injuries,” he adds. “Employees need to be asking: What arc flash protection do we need and what is the hazard potential for the arc flash? Some electrical equipment is capable of a more intense arc flash than other equipment. Employees need to know this and recognize the potential risk to everyone involved in the job, not just the worker actually performing the work. Employees should be trained in the skills and techniques needed to distinguish exposed live parts and work on or near them. Good preplanning is key.”

In addition to improved training and preplanning, adequate safety equipment is essential. Voltage-rated gloves and tools are a must when working on energized electrical equipment. Flame-resistant clothing is needed, even if not required, to protect power plant workers from arc flashes. Shields and hoods are also necessary.

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“Utilities must use all the tools and techniques available to ensure worker safety, which includes planning on how the task can be performed with the equipment de-energized, locked-out and tagged-out,” Foley adds.

Boiler Hazards

According to the National Board of Boiler and Pressure Vessel Inspectors (NBBI), between 1999 and 2003, there were 1,477 reported power boiler accidents, resulting in 143 injuries and 26 deaths (Table 1). (Power boilers include utility boilers as well as boilers used by other industries for cogeneration and on-site power production.)

Beyond training, the best way to prevent power boiler accidents is through proper maintenance and testing of safety devices. This fuel shut-off valve hasn¿t been serviced and the bent handle means it will not close properly. Photo courtesy of Combustion Safety Inc.
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As Table 2 illustrates, there are several causes of power boiler accidents. While low water condition was the number one cause, operator error or poor maintenance was a close second. In addition, operator error or poor maintenance was the number one cause of injuries and second only to burner failure in the number of deaths. It is also important to note that when all boiler types – power boilers, steam heating boilers and water heating boilers – are considered, power boilers were involved in only about 16 percent of the total number of accidents, yet they were responsible for more than 76 percent of boiler-related deaths and approximately 58 percent of all injuries (Table 3).

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John Puskar, PE and principal of Combustion Safety Inc., a Cleveland, Ohio-based consulting company focused on reducing risks and accidents associated with industrial explosions and fires, believes boiler accidents are underreported. He believes that much information regarding boiler and fuel system-related fires and explosions is never sent to NBBI to be eligible for reporting. Puskar estimates the data presented by NBBI represents only about half of all incidents.

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Even if the reported numbers were completely accurate, the NBBI data clearly shows just how dangerous power boiler accidents can be. These numbers emphasize how important it is for utilities and other power generators to do everything possible to mitigate power boiler accidents.

As with electrical hazards, adequate operator training is one of the best ways to reduce power boiler accidents. The American Society of Mechanical Engineers (ASME) code says training has three important and distinct components: providing employees/operators with basic knowledge about their operations, providing information about components and equipment, and making employees/operators aware of hazards. ASME’s boiler code suggests that this last requirement be met by conducting mock upset or event drills.

These mock upset or event drills are the largest single need in boiler related safety training, says Puskar. “We almost never see this done. Our firm has developed a role play-based training module called Combustion Karaoke, which we offer in face-to-face training.” In this module, participants are called to the front of the classroom where the trainers spring upsets on them using visual and audible clues. The trainers ask them to think for three seconds and then explain the appropriate response to the group and tell the group why they chose that response. “This is a fun exercise that makes everyone start thinking,” Puskar says.

Another training issue that Puskar and his co-workers often address relates to changing the culture of sites. “We spend a lot of time fighting people who try to normalize things that are not normal, like ignoring alarms or bypassing safety switches,” Puskar explains. “We focus on something called ‘15 minutes to save your life’ where we stress the importance of a pre-start walk-through equipment checklist that takes only 15 minutes to complete.”

Other things that must be considered when putting together a boiler or combustion equipment safety program include legal compliance issues, such as training records, proof of interlock, valve tightness testing, lock-out/tag-out OSHA compliance issues, operator licensing requirements and state or municipal jurisdictional inspection requirements. Also, do thorough start-up/shut-down procedures exist and are they clear and concise?

Beyond training, the best way to prevent power boiler accidents is through proper maintenance and testing of safety devices. “At many sites, safety-related maintenance tasks are not being performed. We conducted a survey with the Association of Facilities Engineers in September 2004 and found that 26 percent of those operating boilers did not perform legally required annual fuel train automatic valve tightness testing,” says Puskar. “In addition, many sites do little maintenance of manual lubricated plug valves. These valves, critical for shutting off gas at a boiler, are supposed to be resealed at least annually. We find that 60 percent of all lubricated plug valves leak through in the closed position and another 10 percent seize in a completely inoperable condition due to lack of service. Everyone should have a high pressure sealant injection gun, otherwise there is no way to properly maintain these very important fuel shut-off valves.”

The September 2004 survey also discovered that 17 percent of boiler operators did no annual safety interlock testing. “The lack of knowledge regarding what is involved with this testing and how to do it right is astonishing,” Puskar says.

Interlocks are instruments installed to verify that safe conditions exist for lighting off and operating boilers. They can be switches and/or transmitters depending on the size and design of the equipment. They include fuel train-related devices like low and high gas pressure switches, fuel oil temperature switches, atomizing medium switches, fuel oil gun position switches, air flow switches, flame detectors, low fire proving switches for light-offs, proof of closure switches on fuel valves, high steam pressure burner cut-out switches, high and low water cut-offs, auxiliary low water cut-offs, and furnace pressure switches. In some cases, any or all of these can be alarms as well as cut-offs.

All nationally recognized safety codes call for at least annual interlock safety testing of critical components and systems. According to Puskar, there are at least a dozen interlock items to check on almost every boiler, regardless of its size. Documentation that proves testing was performed should include a detailed list of all safety items and their status. In addition to finding failed components, testing sometimes reveals obvious safety violations such as components being bypassed. Only experienced and trained personnel should perform this testing.

The ASME, NFPA and NBBI set most standards for the safe construction, operation and maintenance of boiler systems. Each one publishes a number of codes and standards relevant to its area of expertise. The NFPA codes cover fire and fuel issues, while the ASME and NBBI codes cover primarily pressure vessel and/or waterside issues. “Not only should every boiler operator have a copy of the relevant codes, but he should actually read those codes,” Puskar says.

Puskar also believes most relatively large sites should have flue gas analyzers. “We find that about a third of boiler and combustion related accidents are related to poor fuel-to-air mixtures. Of course, it takes a special and talented person to reset fuel-to-air ratios, so owning a device to find problems is not a license to start tuning your burners. Amateur burner turning is flat out dangerous.”

In addition, Puskar suggests that boiler operators invest in a gas molecule sniffer. “We like them much better than liquid leak detection fluids. They are a lot simpler and more accurate than running around with water bottles,” he says. “It is also a great idea to go down to the local Home Depot or Lowe’s and get a carbon monoxide detector for the control room and/or boiler room area. We’ve found a number of cases where strange things have occurred and ended up jeopardizing the health of boiler operators.”

Upgrading equipment is another way to keep boiler operators and plant personnel safe, says Puskar. “Even though codes are not retroactive, this should not be used as an excuse to never upgrade equipment when it comes to safety issues that could reduce risks. A blithering idiot who has many stressors can operate a highly instrumented, up-to-code piece of equipment. However, the opposite does not hold true. It takes a near genius, experienced person with few stressors to operate a very old, archaic piece of equipment that has many manual procedures and little instrumentation. Because codes are not retroactive, everyone is somewhere in the midst of this continuum.”

Chemical Hazards

Many power plants workers are routinely exposed to dangerous chemicals such as corrosives (acids and bases), oxidizers and solvents. Although there is really no accurate record of the actual number of accidents and injuries that occur because of exposure to hazardous materials in the workplace, it is safe to assume that thousands occur each year. It is also safe to say that the cost associated with injuries from these chemical exposures is far greater than the cost of preventing them or, at least, mitigating their effects.

Although the suitable equipment for drenching dictated in the OSHA requirement isn’t listed, the equipment consists of emergency showers, face washes and eyewashes. Photo courtesy of Haws Corp.
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OSHA and the American National Standards Institute (ANSI) develop and enforce most of the training and safety regulations related to injuries from hazardous chemical exposure. Casey Hayes, engineering manager at Haws Corp., a Sparks, Nev.-based company that designs, manufactures and distributes drinking fountains and emergency drenching equipment, says the OSHA requirements are vague and basically dictate that suitable equipment for drenching must be supplied by the employer.

Although the suitable equipment for drenching dictated in the OSHA requirement isn’t listed, the equipment consists of emergency showers, face washes and eyewashes. This equipment is designed to immediately curtail the harmful effects of exposure to hazardous materials. It uses large amounts of water to drench the affected areas of the body, thus diluting and removing the hazardous materials. ANSI standard Z358.1-2004 provides design specifications that govern how safety showers and washes should be designed, installed and maintained.

Because the regulations are somewhat general and vague, it is primarily up to the employer to determine when and where chemical hazards exist and what type of emergency equipment is needed. It is also up to employers to train their employees on the proper use of emergency equipment and to ensure emergency equipment is properly tested and maintained.

Because the regulations are vague and provide little detail, Hayes offers some tips for mitigating injuries caused by exposure to hazardous chemicals. First, he says, it is important to make sure employees are aware of potential hazards. This requirement is best met through proper training. It is also important for employees to know the exact location of the emergency equipment. Hayes says the equipment can often be hard to find, especially in power plants, where pipes, conduits and other equipment can hide emergency equipment (See sidebar for tips on positioning and locating emergency drenching equipment). Of course, it is extremely important for employees to know how to properly operate the equipment. Again, this requires proper training.

Even if employees have the proper training and know exactly what to do when and if they are exposed to hazardous chemicals, they can still be at great risk of injury if the equipment is not maintained properly. According to Hayes, showers and washes are often not properly tested, and therefore, when called upon, do not operate correctly. “All this equipment needs to be tested weekly to ensure there is sufficient water to the units and to keep the water lines clear of sediment,” he says. Hayes also recommends that emergency equipment be tested thoroughly at least annually to ensure that it still meets all the ANSI standards.

One ANSI standard often overlooked is water temperature. The standard dictates that water temperature in emergency equipment be tepid, which is defined as moderately warm to lukewarm. Although the standard does not dictate a specific, measurable temperature, Hayes says that tepid is usually considered to be somewhere between 60 F (the low parameter) and 100 F (the high parameter). Haws Corp. recommends 80 F. While this may not seem important, Hayes explains that if the water is too cool, it can quickly lead to hypothermia. On the other hand, if the facility is located in a hot environment, the water may become too hot, which can lead to injuries. For example, water temperature greater than 100 F can result in eye injuries. Another thing to consider when it comes to water temperature is that if the water is too cool or hot, an employee may be reluctant to use an emergency facility or may not use it correctly, simply because it is uncomfortable.

Hayes also stresses that because water in an emergency shower is dispensed at a rate of 20 gallons per minute (10 times more than a typical home shower), it is important to consider piping and water storage during installation. “Showers should last for at least 15 minutes. With 20 gallons a minute passing through the shower, a lot of water can be used. Therefore, it is important to design a system to ensure there is enough water at a comfortable temperature for the duration of the shower,” Hayes says.

Monitoring systems for emergency equipment should also be considered. “At the very least, a local alarm with a flashing light and audible horn should be installed,” Hayes says. “Often an employee may be alone in the plant. Without some sort of alarm, no one will know an employee is injured.” An alarm that alerts the control room is even better and is not uncommon. This allows at least a record of the event, and it can allow an emergency response team to be dispatched to the proper locations. Depending on the distance of the control room to the hazard area(s), the alarm can be either hardwired into a control panel or a signal can be sent to the control room via a radio frequency signal, much like the signal used for a garage door opener. p

Keys to Locating Drenching Equipment

• Easily accessible location with no obstacles

• Clearly identified with well-lit signs and showers

• No more than 10 seconds from hazard

– If hazard is on platform or catwalk, emergency equipment must be on same level

If hazard is a strong acid or caustic, emergency equipment must be adjacent to hazard