정량적 위험성 평가에 의한 소규모 건설현장의 안전작업 최적 매뉴얼 설계

Abstract

Due to its characteristics with various types of business, construction industry has an accident rate higher than those of the other industries. Taking a look at the annual accident statistics from the government, the industrial accident rate of all the industries has decreased from 0.71% in 2008 down to 0.59% in 2012, but that of the construction industry has increased from 0.64% to 0.84% consistently. Especially, the accident rate of small-scale construction sites amounting to less than 0.3billion won of total construction price is 3 times as high as the total accident rate of the whole construction industry and the accident victims take 40% of the total of the industry. Although the government has prepared for various kinds of institutional arrangements as a scheme to lower the accident rate at such construction sites, it is in the situation that such a scheme is implemented centered mainly on midium- and large-scale construction sites, but only technology support business through private assignments to accident prevention organizations is implented for small-scale construction sites with less than 0.3billion won of construction price. Implementing such policies resulted into the outcomes that the accident rates of medium- and large-scale construction sites have been maintained at a low level. However, in case of small-scale construction sites with 0.3billion won construction price, since its accident rate is high every year due to the environment with poor safety and insufficient legal and institutional arrangements, etc., it acts as a hindrance factor for lowering the accident rate of the construction industry. As a part of its policy to reduce the industrial accident rate, the government added a new provision into the Industrial Safety and Health Act, Article 41, Paragraph 2, "Risk Assessment" and publicly noticed in order for all of the construction companies to participate in. And regarding to all of the construction sites where construction is commenced after March 13, 2014, a compulsory rule that construction should be commenced after working out some proper safety measures according to the results from a risk self-assessment was specified. However, since the risk assessment system which is currently operated has the structure depending on the qualitative interpretation of risk factors and the subjective judgements of an assessor, it has limits in securing objectivity and reliability. In addition, it is hard to be adopted into construction sites due to the utilization of vast quantity of manuals and instructions which are not appropriate for numbers of work types and reality, the complexity and difficulty of the risk assessment procedures, the errors of statistics, the limits of managing and overseeing and the format dependent on the experiences and ability of personnel concerned at a site. Especially, it is much harder to apply to poor small-scale construction sites lacking specialty personnel. Therefore, it is necessary to develop an efficient manual which is scientifically and systematically designed for making the risk assessment system setteled and activated early while solving the qualitative and subjective problems which occur during the process of institutionalizing, settling and activating the relevant risk assessment techniques and overcoming the limits, so called, the poorness of small-scale construction sites. Therefore, this study was intended to verify the exactness of the risk assessment techniques of the government and to develop the optimal manual for safe working, which secures the reliability and objectivity, by utilizing field surveys and qualitative analysis techniques for making the risk assessment system for small-scale construction sites settled and activated. In order to develop the optimum manual for safe working which can be used often & easily at a small-scale construction site and represents enough characteristics of accidents at a site, 52 work types which are classified by Korea Occupational Safety and Health Agency were more specifically reclassified into 59 work types and accordingly, 59 hypotheses were built and the statistical analysis using data from some field surveys was conducted in order to test the hypotheses. For testing such hypotheses, as the first step, the statistical data from 391 accidents which occurred in Gwangju and Jeonlanam-do from Jan. to Aug., 2013 was used. Regarding to such 391 accidents, the types of accidents were understood and they were classified by each work type. And each risk index was deduced by the risk assessment analysis on the accidents by each work type and the composite risk ratings by each work type were made. As the second step, a questionnair survey questioning the risk level of each among 59 work types and the safety levels of small-scale construction sites were conducted targeting the groups related to small-scale constructon sties and, based on the results, some statistical analyses were conducted. As such statistical analyses, a multivariate regression analysis, a T-test, an ANOVA, a corelation analysis and a factor analysis were conducted and the multivariate regression analysis was used for deducing the risk rankings. For the multivariate regression analysis, 59 work types were used as the independent variable and the safety level of a small-scale construction site was used as the outcome variable. The risk rankings were made by deducing the work types- which significantly influence the outcome variable- and the standard weight for each work type. And the differences of the risk recognition levels between groups regarding to risky work types were deduced by using a T-test and an ANOVA. After that, 17 final risky work types were deduced by comparing the risky work types which were deduced from the 1st and 2nd steps. And the administrative and technical countermeasures against each risky work type were theorized by using various kinds of references and interviews with specialists. In addition, a draft manual for safe working was developed while theorizing the administrative and technical countermeasures and the effectiveness verification for the manual was conducted by distributing the copies of the manual to specialists. For such an effectiveness verification, the specialists were asked to fill in the pair-wise comparison questionnaires regarding to the convenience, appropriateness, reduction, satisfaction level, depth of applicability and utilization level of the manual. And first of all, a preferential ranking analysis was conducted by using the AHP technique with the collected questionnairs and, regarding to the items which are evaluated relatively as a low ranking, some modification works were conducted and the modified manual and the first developed one were compared in order to complement the contents of the administrative and technical countermeasures. And then, the development of the final manual for safe working was confirmed. Finally, in order to find out the effects of the manual for safe working, the copies of the finally completed manual for safe working were distributed to small-scale construction sites to be used there and the effectivenss was deduced by making the respondents evaluate their recognition levels after using the manual based on 6 items which were used in the AHP technique. Therefore, the optimal manual for safe working which is appropriate for small-scale construction sites was developed and evaluated. The researcher of this study intended to develop the manual after designing most properly while considering the characteristics and environments surrounding small-scale construction sites as much as possible. However, unless a good manual is aggressively used at a small-scale construction site regardless of how good the manual is, it can be thought that it is meaningless. Thus, the manual was intended to help the efficient safety management by selecting and focusing on while reducing some hold-ups of safety management which are suffered at small-scale poor contruction sites. Therefore, it is intended to contribute for reducing similarly repeated conventional accidents occurring at small-scale construction sites and the overall accident rate of the Korean construction industry.