Risk-Based Analysis and Engineering of Safe Distances Between Occupied Structures and Processing Equipment

Abstract

API RP 752 (2009) allows for the evaluation of building locations to use three different assessment approaches: 1. Consequence-based analysis: This approach generally requires that the impacts from maximum credible events (MCEs) be calculated or modeled to determine the impact on a structure. 2. Risk-based analysis: Use of risk-based analysis involves conducting a quantitative analysis to determine risk on the basis of the consequence and the frequency of the hazardous event. 3. Spacing-tables approach: Under API RP 752 (2009), the spacing-table approach is to be used only when determining the minimum distance from a fire to a building. These tables are not appropriate for toxic or explosive events for which the consequence is dependent on the release rate, length of release, wind direction, material released, and many other factors. API RP 752 (2009) was developed primarily for use at facilities that include natural-gas plants, natural-gas-liquefication plants, and other onshore facilities covered by the Occupational Safety and Health Administration (OSHA) process-safety management standard (OSHA 1992). API RP 752 (2009) provides an excellent overview of the issues and factors regarding hazards associated with buildings and provides references as to where additional information can be obtained. The recommended practice does not provide information relating to an oil-production or a gas-treatment facility, detailing out critical items such as MCEs, impacts from hazardous incidents, acceptatble risk criteria, and risk analaysis. The objective of this paper is to present a detailed approach that can serve as the basis for determining safe distances between buildings and processing equipment.