Design of Standard Engineering Model to Improve Occupational Health and Safety for Boiler in Sudan

Abstract

This study has been carried out to design an engineering standard model to improve occupational health and safety steam boilers in industrial sector in Sudan, due to the lack of a standard model that determines the degree of control. In this work the boiler system was classified to four basic nodes, the failure of each of them can lead to catastrophic event. These nodes were named as insufficient fuel pressure, insufficient combustion, insufficient water level and over pressure. The sevens step method, which were provided by Environmental Protection Agency (EPA), was used to identify the requirement Safety Integrity Level (SIL) for each node control system, the boiler control system was classified to four levels (SIL1, SIL2, SIL3, SIL4). Fault tree analysis, which is a quantitative risk assessment technique, was used to study the reliability of boiler systems and identify safety integrity level (SIL) for an existing control system. Redundancy and voting approaches were used to improve the existing boiler control system so as to achieve the desired safety integrity level and comply with the specific standards. A boiler control system information at localized company producing ethanol were used to assess the model accuracy, the result showed that the existing SILs were (0.0004, SIL3) (0.001,SIL2) (0.005, SIL2) (0.000007, SIL4) for each node respectively, that did not meet the designated standard which are (SIL3, SIL2, SIL1, SIL3 ) for the four nodes respectively. After the improvement by applying redundancy control for the four mentioned nodes, the new SILs were found to be (0.000006, SIL4) (0.0011, SIL3) (0.0004, SIL3) (0.0000007, SIL4) for the four nodes respectively, which agreed with the desired standards. Due to a lack of boiler standard in Sudan this standard is recommended to be adopted by authorized body so as to prevent and reduce accidents, preserve life and economy of the Sudan.