Application of Probabilistic Risk Analysis Techniques to Evaluate the Role of Fire Dampers in a Cascaded Ventilation System

摘要

The design of chemical processing or nuclear facilities requires the control of toxic chemical or radioactive gases to prevent their release into the atmosphere. For safety, all contaminated room air must pass through absorbent filters before being released to the outside environment. For the medium to large facility, large air supply and exhaust systems are designed to move air through the facility. Because of the resulting negative pressure of the cascaded ventilation system, the building structure and the internal system must be designed to meet many accident conditions. Safety design features are required to prevent accidents and mitigate accident severity. Choosing capital spending alternatives to provide design safety features should depend on the accident conditions, occurrence rate, and accident severity. Traditionally, accident analysis only focuses on severities. A probabilistic risk analysis (PRA) is proposed to supplement the traditional problem assessing methods. This paper assesses fire damper closures using risk analysis in evaluating the various design alternatives. The consequences of fire damper closure in a large cascaded ventilation system depend on both the facility's wall structure and the ventilation system size. There are always a variety of design alternatives to mitigate hazards and several design alternatives are illustrated. The proposed evaluation methodology can be applied to help in managerial decision.