(100b) Guidelines for Sensor Siting at Industrial Facilities

Industrial facilities must conduct their business in a way that protects people, the environment and property, and continually seeks ways to enhance that process. The public's expectations for the performance of chemical plants in their communities are becoming increasingly stringent. Tolerance for lesser events, such as nuisance odors in their neighborhoods, is gradually decreasing.

Faced with these challenges, chemical companies need to design and implement a sophisticated emergency system to manage and respond to hazardous chemical spills. This system must cover two elements: a network of monitoring devices deployed at a physical or a virtual fenceline at the plant, and a computerized emergency response system equipped with GIS mapping and data acquisition. This computerized system has to integrate the real-time meteorological and gas concentration data with a dispersion model to track the trajectory and impact of the plume and, therefore, improve decision making and resource deployment in emergency conditions.

Many companies lack a specific guideline for implementing a cost effective gas detection system on site for an efficient emergency/community response solution. The objective of this paper is to provide a guideline for gas sensor siting. Two methods are proposed, based on whether the objective is to solve an odor complaint or an emergency response issue. A number of factors that affect sensor placement, such as a chemical and its concentration level of concern, sensor lower threshold limits, population distribution, prevailing wind conditions, and several others are discussed. A Gaussian dispersion model is utilized to obtain concentration profiles at the plant fenceline and in the surrounding communities. The results from the two methods are compared to show how a plant's objective affects the number of sensors and their placement.