Apr 09, 2014

The potential for accidental release of toxic chemicals to the environment is a daily threat for many industrial facilities and plants. These releases can occur very suddenly and unexpectedly, putting employees and the public at risk of injury or death, and the surrounding environment at risk of damage or destruction. A consequence modeling analysis is a powerful tool (and sometimes a regulatory requirement) in order to understand the impact that a potential release could have on personnel, equipment, and the surrounding community. Modeling can be used to address a full spectrum of threats including toxic/flammable gas dispersion, explosions, and fires (thermal radiation).

Consequence modeling is used to predict the behavior of a hazardous release, and provides a better understanding of the potential impacts caused by the release. There are many benefits to performing this type of analysis, ranging from regulatory compliance to incident reconstruction. The list below shows our top five reasons why consequence modeling is beneficial for industrial facilities nationwide:

  1. U.S. EPA Risk Management Program (RMP) Offsite Consequence Analysis
  2. Real-Time Assessment of Hazards in Emergency Situations
  3. Facility Safety and Design Improvement
  4. Reconstruction of a Past Incident
  5. Emergency Evacuation Preparation & Planning

U.S. EPA Risk Management Program (RMP) Offsite Consequence Analysis

The U.S. EPA Risk Management Plan (RMP) was initiated when Congress passed the Clean Air Act Amendments of 1990, and is designed to reduce the risk of chemical releases on the local level and assist first responders and citizens in understanding local chemical hazards. Based on section 112(r) of the Clean Air Act, any facility that produces, handles, distributes, processes, or stores certain chemicals must develop, prepare, and submit a RMP to the U.S. EPA. The Offsite Consequence Analysis (OCA) component of RMP's is part of the hazard assessment, in which an OCA must be conducted for the worst-case release of the regulated chemicals (e.g., a rupture of the largest ammonia tank in an ammonia process in which the total contents are released). In addition to this worst-case release scenario, an alternative release scenario may also be performed for the OCA that shows how safety procedures may make the worst-case scenario less likely. By using a model for these analyses, the user may input data related to the release (e.g., source data; chemical properties; meteorological data) in order to quickly obtain results from the worst-case scenario and alternative scenario. More information on RMP's and OCA's may be found in the recent Environmental Quarterly (EQ) article, Complying with EPA's Risk Management Program.

Real-Time Assessment of Hazards in Emergency Situations

When a hazardous chemical release occurs, time can be at an extreme premium for emergency responders. A real-time consequence analysis, using pre-configured scenarios that require minimal input (such as current wind speed and direction) at the time of an incident can be an invaluable resource in guiding response efforts. By identifying likely safe zones and hazard areas, modeling can eliminate some of the uncertainties faced by emergency personnel and facilitate a safer, faster, and more effective response.

Facility Safety and Design Improvement

A consequence modeling analysis may be used to improve the overall safety at a facility by identifying areas likely to be impacted by a release with modeling and reducing the exposure of employees to this identified area. For example, if an area of high risk is identified on one side of the facility, then the facility design may be improved or developed by putting office space on the opposite side of the facility from this hazardous area. Modeling can also be used to shape building design, such as assessing the need for blast-resistant building components.

Reconstruction of a Past Incident

For a variety of reasons, ranging from safety improvements to litigation purposes, the reconstruction of a past incident through consequence modeling is a powerful tool. By using a consequence modeling analysis, the chemical release and impacts may be analyzed in order to provide a better understanding of impacts on employees and the surrounding community, as well as assist in the response planning in case a similar event occurs in the future.

Emergency Evacuation Preparation & Planning

Emergency response plans, including evacuation zones and routes at the facility- and community-level, can be improved by performing a consequence modeling analysis. By more precisely quantifying likely impact zones, better and faster response to an incident can be made. Also, by modeling a variety of release scenarios beforehand, emergency planners and first responders can better understand the risks involved in a specific scenario very easily and quickly when it occurs.

Want to Learn More?

BREEZE Software, a division of Trinity Consultants, has been assisting plant managers and engineers with their consequence modeling for years by offering to perform the modeling analysis on a consulting basis, and by providing a comprehensive tool for accidental chemical release and consequence modeling, BREEZE Incident Analyst.

To learn more about consequence modeling and how it may benefit your facility, email the BREEZE Team at breeze@trinityconsultants.com.