الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Nowadays, Meeting the international Safety measures and regulations by developing only on a good design is impossible especially with the current advanced and Complex technologies in the industry of chemical Engineering of Petroleum refining, gas Processing and Petrochemicals which considered one of the riskiest industries which require a high integrity level of safety measures.
Many Methods have been developed over the years for detecting the number of risks that occur from such Processes, allowing for the identification of a wide spectrum of hazards ranging from equipment failures to human factors for increasing safety, minimizing downtime, and preserving the environment.
A process hazard analysis (PHA), such as a Hazard and Operability Study (HAZOP), is an important technique for detecting possible hazards. A PHA, on the other hand, can only provide a qualitative assessment of whether enough measures exist to limit the risks. necessitating the use of more advanced methods and studies to develop and assess the riskiest and most critical scenarios.
Integrity of Safety Layer of Protection Analysis (LOPA), for example, is a risk management approach used often in the chemical process and petroleum industries that may give a more extensive, semi-quantitative assessment of the risks and layers of protection associated with hazard scenarios.
SIL stands for Safety Integrity Level. A SIL is tool used to measure the system Safety performance, in terms of probability of failure on demand (PFD). The more SIL rating, the more safety system performance the lower probability of failure on demand for this system, however with the conservative execration for SIL rating during design will results in more design cost and complexity also more installation, operation and maintenance complexity and cost.
This Thesis presents systematic approach of reducing the total Safety Integrity Level “SIL” rating for the Safety Instrument System “SIS” of Vacuum Distillate Unit “VDU”. The method is applying the applicable conditional modifiers such as Ignition Probability and occupancy factor during developing Layer of Protection Analysis Method “LOPA”. The results of this approach that the SIL rating of VDU feed Node is reduced from SIL 3 to SIL 2 by using the applicable condition modifiers. Such Reduction in SIL rating without reducing the required safety measures and requirements has a remarkable impact for the total cost reduction of the unit and reduce design, installation, operation and maintenance complexity and cost.