مدیریت ریسک ایمنی برای ساخت خط توزیع و انتقال برق
|کد مقاله||سال انتشار||مقاله انگلیسی||ترجمه فارسی|
|801||2013||9 صفحه PDF||20 صفحه WORD|
Publisher : Elsevier - Science Direct (الزویر - ساینس دایرکت)
Journal : Safety Science, Volume 51, Issue 1, January 2013, Pages 118–126
مروری بر حوزه ادبی
عملیات انتقال و توزیع (T&D) الکتریسیته
اثرات جریان های الکتریکی با ولتاژ بالا روی بدن انسان
کمّی سازی ریسک های ایمنی
تلفیق و مدیریت ریسک ایمنی
روش های تحقیق
فاز اول: مصاحبه های اکتشافی
مرحله 2: کمیت بندی ریسک های ایمنی و اثرات تلفیق ریسک
نتایج و مباحثه
تحلیل و کاربرد داده ها
Prior research has established that electrical contractors involved in the construction and maintenance of electrical transmission and distribution (T&D) lines are at extremely high risk of electrocution. The result of inadvertent contact with T&D lines often is death or severe injury that involves damage to internal organs, musculoskeletal disorders, neurological damages and severe burns. The Electrical Safety Foundation International has demonstrated that contact with overhead power lines has been the single largest cause of electrical fatalities over the last decade. To reduce this disproportionate injury rate, electrical contractors implement many strategies such as the use of rubber insulating equipment, and locking devices. Unfortunately, these strategies are often cost-prohibitive in certain construction and maintenance scenarios. Therefore, electrical contractors are faced with complex decisions that involve comparing the cost of injury prevention with the expected safety benefit. This paper presents research that objectively evaluated the risk associated with common T&D construction tasks and the effectiveness of specific injury prevention techniques. The research team then developed a decision support framework that provides electrical contractors with objective safety and cost feedback given specific project characteristics. The results indicate that many of the effective strategies implemented to reduce T&D electrical injuries are very costly (e.g., de-energizing lines). Consequently, under most conditions, the costs of injury prevention far outweigh the cost savings associated with the reduction of injury rates. The implication of these findings is that T&D electrical contractors must highly value the non-monetary benefits of injury prevention in order to improve safety in their sector.
According to the US Energy Information Administration (2010), more than 4 billion mW h of electricity is generated annually in the United States to serve more than 300 million people. This electricity is transmitted for consumption through electrical transmission and distribution (T&D) lines. The nominal voltage in bulk transmission lines can be as high as 750 kV, which can cause instant death when contact is made (Short, 2004). Workers involved in the construction and maintenance of these electrical T&D lines are at extremely high risk of electrocution. In fact, according to the Electrical Safety Foundation International (2010), contact with overhead power lines accounted for an average of 43% of all electrocutions between 1992 and 2009. Other major causes of occupational electrocutions included contact with wiring, transformers, or other electrical components (27%) and contact with the electrical current of machines, tools, appliances, or light fixtures (17%). Among all occupations, the Electrical Safety Foundation International (2010) found that construction contractors account for the highest rate of electrocutions. Within the construction trade, electricians accounted for about 17% of the electrocution fatalities; construction laborers accounted for 9%; and roofers, painters, carpenters, and maintenance workers incurred a total of 7%. Behind construction, T&D line workers have the second highest electrocution rate. The Bureau of Labor Statistics (2010a) estimated that among the 192 recorded electrocution fatalities in 2008, 53% involved T&D workers who contacted overhead power lines and the National Institute for Occupational Safety and Health (2009) documented that 80% of fatalities among linemen have occurred due to direct contact with T&D power lines. This injury rate caused the Bureau of Labor Statistics, 2010a and Bureau of Labor Statistics, 2010b to classify T&D line construction and maintenance as one of the most dangerous jobs in the American economy. Unfortunately, a thorough literature revealed no significant research into the proximal causes or methods of prevention for T&D fatalities. The impacts of T&D electrical injuries are substantial. The result of inadvertent contact with T&D lines is often death or severe injury that involves damage to internal organs, musculoskeletal disorders, neurological damage, and severe burns (Lee et al., 2000). Such injuries cause long-term physical and emotional distress to workers and their families. In addition, these injuries and fatalities result in substantial economic expenses such as: higher insurance premiums, medical cost, compensations, lost productivity, administrative costs, and others (Everret and Frank, 1996, Ferret and Hughes, 2007, Oxenburgh and Marlow, 1996 and Tang et al., 2004). According to Waehrer et al. (2007), the construction private sector accounted for $11.5 billion in fatal and non-fatal injuries in the year 2002. The electrical T&D sector contributed greatly to these statistics. In fact, the average cost of each electrical fatality was $4 million and the cost of each lost work time injury was $42,207. Despite the high injury and fatality rates and their severe financial and personal impacts, the electrical T&D industry continues to grow at an alarming rate. Research in the electrical T&D sector has predicted that recent technological advances will force utility companies to construct new lines, maintain existing lines, and upgrade their performance (Balducci et al., 2002). It has also been estimated that the demand for electricity will increase by more than 1 trillion kW h from the years 2003 to 2020 Further, studies by Chupka et al. (2008) have shown that, the electrical utilities will have to make an investment of $1.5–$2.0 trillion by the year 2030 to keep up with the pace in demand. These investments to enhance the T&D infrastructure will likely increase the volume and complexity of T&D electrical line work over the next 20 years (ESFI, 2010). Electrical utilities and contracting companies clearly need to consider injury prevention strategies that reduce the frequency and severity of injuries and their associated monetary and non-monetary costs. When addressing this issue, electrical contractors and utility companies are faced with complex decisions involving weighing the cost of injury prevention against the expected safety benefit. The purpose of this study was to objectively evaluate the costs and benefits of safety management techniques in the electrical T&D sector of the US construction industry for commonly-encountered work scenarios. The associated objectives of this research study were to: (1) identify common work tasks performed around T&D lines and safety strategies used by utility companies to prevent injuries; (2) quantify the safety risk associated with each work task using a combination of opinion-based and empirical data; (3) quantify the percent risk reduced by the various injury prevention strategies; and (4) apply a risk-based contingent liability model developed by Hallowell (2011) to analyze the cost–benefit of the injury prevention strategies under specific work scenarios. The result is a stable, valid, and reliable decision support tool that provides critical safety and cost feedback that practitioners can use to make informed decisions that enhance both safety and financial performance.
نتیجه گیری انگلیسی
The objective of this study was to quantify safety risk for projects involving the construction and the maintenance of transmission and distribution lines at the activity level and to evaluate various injury prevention techniques used in the industry. Interviews and questionnaire surveys were conducted to populate the data and to validate the study. A decision support framework was developed that provides electrical contractors and utility companies with objective safety and cost feedback given specific project characteristics. The reader should note that the data presented in this paper and the associated analyses only apply to electrical T&D construction and maintenance. The data do not apply to building construction workers who account for the greatest rate of electrocutions. The analysis computed the safety risk associated with each task and suggests that operating equipment near energized lines pose the highest risk among the activities done on or near T&D lines. Other tasks with high risk profiles include energizing line and equipment prior to placing in-service; excavation/trenching and installing foundations; and climbing poles and operating on aerial lifts. Among the injury prevention methods, following safety procedures and regulations and de-energizing lines and equipment prior to work were highly effective, although certain strategies are cost-inefficient. The framework also allows the evaluation of the cost effectiveness of the strategies in controlling injury rates. Finally, unlike other studies (e.g., Hallowell, 2010a, Hallowell, 2010b, Jaselskis et al., 1996 and Hallowell and Gambatese, 2009; Lancaster et al. Jervis and Collins, 2001 and Smallman and John, 2001) that showed considerable economic returns, the results of this study indicate that the economic returns obtained in the T&D industry by the implementation of injury prevention strategies is lesser in-comparison to the general construction industry. This indicates that the T&D industry has a higher cost-utility (i.e., investment into safety interventions exceed economic returns), which values non-monetary benefits (e.g., reduced worker turnover) and aims to reduce social costs (e.g., social equity) associated with injuries. The results of this study will allow electric utilities and contractors to evaluate risk levels associated with various projects based on the tasks involved and in designing efficient safety programs based on injury prevention capability. Enhanced resource allocation to control injuries while performing activities with high risk profiles will be facilitated based on the risk quantification concept. For instance, while operating equipment in the vicinity of power-lines, the use of barriers and signs may serve as an indicator of the presence of an active hazard which may help prevent incidents. The framework created for decision making, also incorporates the cost of the strategies, which will allow for rational decisions based on the resources available and the financial implication of injury prevention measures. Finally, several researchers have proposed that tasks executed concurrently in a worksite may increase the base-level risk (Lee and Halpin, 2003; Sacks et al., 2009; Rozenfeld et al., 2010 and Hallowell et al., 2011) and likewise the synergistic effect of injury prevention methods may enhance safety performance (Hallowell et al., 2011). Thus, it is suggested that future research be conducted in establishing the risk interactions between different activities and injury prevention methods. Also, studies that include the social benefits obtained through injury prevention may need to be explored in the design of safety programs.