Accidental Risk Assessment on Atmospheric Distillation Column in Oil Refinery
Please cite this article as: Babaarslan N., Alpbaz M., Cabbar Y., 2014, Accidental risk assessment on atmospheric distillation column in oil refinery, Chemical Engineering Transactions, 36, 475-480 DOI: 10.3303/CET1436080 Accidental Risk Assessment on Atmospheric Distillation Column in Oil Refinery Neslihan Babaarslan, Mustafa Alpbaz, Yavuz Cabbar a Turkish Republic Ministry of Labor and Social Security, Inonu bulvari no:42, 06520 Ankara/Turkey b Ankara University, Chemical Engineering Dept., Engineering Faculty, Dogol st. 06100 Ankara/Turkey c Ankara Chamber of Industry (ASO), Ataturk bulvari no:193, 06680 Ankara/Turkey ncelik@csgb.gov.tr
Small enterprises and major hazards: How to develop an appropriate safety management system
Abstract Many small and medium sized enterprises (SMEs) are obliged to adopt a Safety Managements System (SMS) by the Directive 2012/18/EU for the control of Major Accident Hazards (Seveso III). The difficulties of implementing an SMS within a small sized work organization are well known by practitioners, including inspectors and auditors and have been discussed in many recent papers. In the present paper is discussed a new method, based on the bowtie model, to build an easy and effective SMS. The very core of this method is a “safety net model”, which is able to connect in a network all the tangible and intangible elements of safety, including equipment, operating instructions, procedures and safety documents. This safety model has been used as the core of a smart application, the strength of which is the workers' contribution. The application allows the users to build step by step an SMS. It starts from a first version based just on regulations and standard codes (version 0), then it integrates internal knowledge through the bowtie paradigm (version 1). Near misses' discussion is used to transfer actual workers' experience into the system, to get intermediate improvement of the SMS (version 1.x). At the end audit may be used to a major release of the SMS (version 2). The full cycle has been tested at two small Seveso establishments: a galvanic plant and small glue manufacturer.
Reliability assessment of safety instrumented systems subject to different demand modes
Abstract Safety instrumented systems (SISs) are commonly used in the process industry, to respond to hazardous events. In line with the important standard IEC 61508, SISs are generally classified into two types: low-demand systems and high-demand systems. This article explores this classification by studying the SIS reliability for varying demand rates, demand durations, and test intervals. The approach is based on Markov models and is exemplified by two simple system configurations. The SIS reliability is quantified by the probability of failure on demand (PFD) and the frequency of entering a hazardous state that will lead to an accident if the situation is not controlled by additional barriers. The article concludes that very low-demand systems are similar and may be treated as a group. The same applies to very high-demand system. Between these group, there is a rather long interval where the demand rate is neither high-demand nor low-demand. These medium-demand systems need a specific treatment. The article shows that the frequency of entering into a hazardous state increases with the demand rate for low-demand systems, while it is nearly independent of both the demand rate and the demand duration for high-demand systems. The PFD is an adequate measure for the SIS reliability for low-demand systems, but may be confusing and difficult to interpret for high-demand systems.