O&M

Scaffold Safety in Coal-Fired Power Plants

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Scaffolding typically ranks near the top of the U.S. Occupational Safety and Health Administration’s most-frequently cited standards. However, developing a strong safety culture and implementing an effective scaffold safety program could help companies avoid costly fines, and more importantly, prevent deadly accidents.

Going to work in a controlled and safe environment is not an unreasonable expectation for any power industry worker. In a power plant, a level of danger is expected because it is inherent to the job, but this is only more reason for companies to take employee safety seriously. The best organizations are those that understand that a safe workplace is not only right for their employees, but also for their bottom line.

The Occupational Safety and Health Administration (OSHA) releases a list of the 10 most frequently cited safety and health violations each year. The list is developed from nearly 32,000 inspections of workplaces by federal OSHA staff. One surprising thing about the data is that it rarely changes; fall protection and scaffolding are usually near the top of the list.

Dangers associated with scaffolding should not be overlooked by the power industry. It is safe to say that every power plant in the world uses scaffolding in some way, shape, or form. It is a critical component for many maintenance activities where permanently installed access is not possible or practical. Often, plant maintenance personnel are trained to install scaffolding, but it is not uncommon for scaffolding contractors to be brought in for large jobs too.

The scaffolding industry as a whole has made great strides in improving employee safety records. This positive trend can be attributed to not only government regulations, but also to more companies understanding the importance of building a strong safety culture. Top performers in the industry realize that implementing a safety program that becomes imbedded in the culture of the organization not only benefits its workers, but also helps the organization become more competitive in the marketplace.

Hazards in the Workplace

Coal-fired power plants present several occupational hazards to workers during routine work activities. Occupational hazards include extreme heat stress, toxic chemical exposure, falls, and tight working conditions (Figure 1). Working in a coal-fired power plant can even prove deadly in some cases, due to the risk of fires, explosions, and serious respiratory issues. Because coal dust is combustible, it is critically important to take safety precautions for the protection of the plant workforce and nearby communities.

Fig 1_Scaffold
1. Tight spots. Scaffold erection in the boiler pendant area can require unusual modifications to account for blown tubes, slag, and other obstructions. Courtesy: StructSure Scaffold & Insulation

Extreme heat exposure is a prevalent issue for workers. Temperatures can exceed 150F in some plant locations. Heat from a boiler will rise to the top of the unit and get trapped by the roof, creating even higher temperatures as workers approach the top floor of the facility. Implementing the correct precautions is important for anyone working in close proximity to the boiler and at high levels. Working in these extreme conditions is a very real threat to employee safety and health.

Employees can be exposed to dangerous chemicals and toxicants including acid gas and fly ash. Acid gas is a byproduct of burning coal that is normally removed using air quality control systems prior to flue gases and water vapor being discharged to the stack. However, if a line, duct, or boiler wall begins to leak, acid gas can escape into an area that could potentially be occupied by plant employees and contractors. The gas, which is several hundred degrees, can damage a worker’s lungs, prevent sufficient breathing, and cause painful eye irritation.

Fly ash poses another health hazard in coal power plants. Fly ash consists of small particles of unburned coal or ash dust that migrate through units during operation. Fly ash can eventually coat some surfaces in the plant with a small layer of dust, including deck grating and equipment. Some older or poorly maintained plants can have ash accumulation measured in inches in some spots. In addition to eye irritation concerns and difficulty breathing, fly ash can result in an increased risk of slipping or falling. Fly ash is increasingly dangerous, because it is easily agitated and becomes airborne when stepped on.

Falls are a prevalent hazard for workers and are among the most common causes of serious work-related injuries and deaths. The risk is particularly high when installing, working on, or disassembling scaffolding. Power plant employees can be at risk from falling off of overhead platforms and elevated workstations or through holes in floors and walls.

Additionally, working in tight proximity around boilers, piping, electrical cables, and other power plant equipment presents an occupational hazard. Contractors, who may not be familiar with specific plant systems, have to navigate around these utilities to properly complete assigned repair or maintenance tasks.

In many power plants, the 3-foot-wide electrical cable trays that carry cables across the plant obstruct large areas where scaffolding needs to be erected (see sidebar). Oftentimes, scaffolding contractors have to build scaffolding around pipes and electrical lines in both vertical and horizontal orientations (Figure 3). Working in tight proximity to the plant equipment increases the risk of injuries from chemical and heat burns, respiratory harm, eye irritation, and electrical shock, which could result in death.

Virtual Reality Improves Power Plant Scaffolding

Traditionally, scaffolding for coal-fired power plant maintenance was designed and approved using engineered drawings. In the 1980s, two-dimensional computer-aided design began replacing the drafting board for creating such drawings. Since then, three-dimensional visualization has become increasingly common, but the result is still a drawing on paper that doesn’t help identify potential problems before the structure is built.

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2. Complex design. The shape of a boiler’s V-bottom can make designing scaffolds difficult, but virtual reality systems can make it easier. Courtesy: Avontus Software

However, virtual reality (VR) can greatly alleviate the unique challenges and problems of scaffolding design in the power industry. VR—a computer-generated environment that allows a design to be fully explored—offers approval and troubleshooting efficiencies even before staging begins. Some of the key efficiency areas, specifically for power plant boilers, include the V-bottom, dance floor, pendants, and external staging areas.

V-Bottom. Given the incredible height of most boiler scaffolds, the loads transferred to the beams in the v-bottom can be tremendous. In some cases, scaffold legs are welded to the floor to prevent those forces from being transferred to the main supporting members, but often a ladder type of system is used (Figure 2). The intricate details of the structure are very difficult to see in 2-D, and in 3-D there are a limited number of predefined views that can be printed and viewed. VR allows the ability to “fly through” the scaffold.

Dance Floor. Commonly referred to as a “dance floor,” a full deck is frequently assembled in a boiler’s bullnose area during major outages. Visualizing the location of this deck can increase safety, as its main purpose is to prevent debris from falling down into the main boiler structure.

Pendants. Often, the scaffold in the pendants is very complex and requires a sort of improvisational build to make it fit the as-found conditions. While a VR tool will not completely eliminate the need for flexibility, it allows scaffolding designers to navigate the region, which can help determine difficult areas before the scaffold is built.

External Staging Areas. The ability to plan the pre-job staging of large amounts of scaffolding materials in areas throughout the power plant can result in tremendous labor savings. Individuals who will be constructing the scaffold can review and approve these strategic areas, enabling unprecedented labor planning during the review stage.

VR is a game-changer in power plant scaffolding projects. With the ability to see a plan from all angles, designers can potentially reduce problems that might otherwise only be found during the job. Moving through a design in VR gives workers a way to see a design as close to reality as possible.

Brian Webb is CEO of Avontus Software (www.avontus.com).

Fig 3_Scaffold
3. Tricky geometrics. When constructing scaffolding, workers have to work with the space they have. Unfortunately, in power plants that space is often full of pipes, electrical lines, and other obstacles that have to be built around. Courtesy: StructSure Scaffold & Insulation

Safety Protocols and Training Programs

Implementing a scaffold safety program (SSP) is one way to promote a safer working environment. However, an SSP cannot be successful unless a company has an effective safety culture. A strong safety culture is a behavior-based program that stresses leading indicators versus lagging indicators. To achieve a successful safety culture, it is important to continuously promote safety values within the workforce. Below are a few recommendations for building a strong safety culture:

■ Implement a standard training and operating program (S.T.O.P.)

■ Perform regular jobsite visits by corporate safety department personnel

■ Develop a proactive, behavior-based safety incentive program

■ Provide regular and consistent messages from management

■ Maintain a well-trained and experienced workforce and leadership team

■ Employ a firm disciplinary policy

The success of a SSP depends on the willingness of top management to demonstrate a long-term, serious commitment to protect every employee from injury and illness on the job. Managers need to display leadership through effective accountability and recognition of behaviors and results.

OSHA and the American National Standards Institute (ANSI) develop and enforce most of the training and safety regulations related to injuries from hazardous chemical and physical exposure. OSHA requires all scaffolding companies to furnish employees who erect or work on scaffolds with appropriate training. OSHA mandates the development and implementation of an effective formal SSP.

According to OSHAcademy Occupational Safety & Health Training and the Scaffold Safety Program Management course, employers in the construction industry are required to provide a safe and healthful workplace, including:

■ Providing employees with sanitary and safe working conditions

■ Assigning safety and health responsibilities

■ Giving safety and health designees authority to correct hazards

■ Ensuring employees may voice safety and health concerns without fear of reprisal

■ Informing employees of worksite hazards

■ Coordinating hazard communication with other employers on site

■ Posting the OSHA state or federal poster

The regulations set forth by OSHA are somewhat vague, leaving it primarily up to the employer to determine when and where chemical and physical hazards exist and what type of protection and emergency equipment is needed. It is also up to the employer to train their employees on the proper use of protection and emergency equipment and to ensure that the equipment is properly tested and maintained.

Protective Equipment

Personal protective equipment (PPE) refers to protective clothing, helmets, goggles, cut-resistant gloves, respirators, or other garments and equipment designed to protect a power plant worker’s body from injury, exposure, or infection. PPE addresses physical, electrical, heat, chemical, biohazard, and airborne particulate matter hazards.

When engineering control measures are not feasible to protect workers from breathing air contaminated with harmful dusts, fogs, fumes, mists, gases, smokes, sprays, or vapors, workers must wear an appropriate respirator. The type of respirator required varies based on the hazards present in the work environment. In atmospheres that are immediately dangerous to life or health, a self-contained breathing apparatus might be required, while in a less dangerous area an air-purifying respirator might suffice. Understanding the hazards is vital to selecting the appropriate respirator.

Additionally, eye protection, such as safety goggles or safety glasses, is used to provide protection in instances where exposure to fly ash, acid gas, and other hazards could cause an eye injury. Safety goggles provide better protection than safety glasses in preventing eye injuries. To prevent fogging, safety goggles should have high airflow or have an anti-fog spray applied.

Fall protection systems are another necessary aspect of worksite protection. Personal fall-arrest systems should be used for workers on suspended scaffolds. The system usually consists of a full-body harness, lanyard, rope grab, independent vertical lifeline, and an independent lifeline anchorage.

It is important to note that fall protection is only as good as its anchorage. Anchorage points are independent points on structures where lifelines are securely attached. These points should be able to support at least 5,000 pounds per employee and preferably 5,400 pounds for a fall of up to six feet or support at least 3,000 pounds for a fall of two feet.

Preplanning

The preplanning process requires the evaluation of each job on a case-by-case basis to determine the safest possible way to complete a project. Scaffolding contractors conduct a job safety analysis (JSA), during which they examine the job site and make a list of each environmental factor that could be a potential harm. JSAs include the identification of exit routes, eyewash stations, and other safety resources for employees.

Once a JSA is conducted, the safety department will conduct a safety meeting with employees and give them the opportunity to discuss any potential issues directly with the corporate safety department. Permitting employee feedback during safety meetings has proven to be a vital part of promoting an excellent safety culture.

Beyond the required JSA, scaffolding contractors should have their own sets of safety precautions and employee guidelines. The safety department and company management should provide periodic training on these company-wide regulations and for relevant topics as dictated by the needs of the work site and any changes in hazards associated with the scope of work (Figure 4).

Fig 4_Scaffold
4. Don’t look down. Large scaffolds, such as the one in the boiler shown here, require well-designed support points and accurate load calculations. Courtesy: StructSure Scaffold & Insulation

Additionally, the project manager and general manager should maintain regular, periodic visits to all of the job sites. As with the corporate safety department, management should make employee safety observations and give immediate feedback and corrective action, when necessary.

Most employees in both the power and scaffolding industry want to be part of an organization that invests in a safety program. If employees perceive that safety is not a priority for the company, their behaviors and attitudes are adversely affected. An investment in a safety program that focuses on hazard identification, training, prevention, and assessment will not only help reduce losses and increase overall safety compliance records, but it could be the difference between being an industry leader or just another company. ■

Matt Skidmore is regional safety director at StructSure Scaffold & Insulation.

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