Effective disaster management can go a long way in mitigating the damage caused by natural catastrophes, thereby increasing plant safety.
Today, natural disasters are on the rise around the world, both in terms of their magnitude and their frequency. Unfortunately, the same holds true for India as well. Over the past decade, the number of natural and manmade disasters has increased significantly. The global data on reported disasters from 1999–2003 indicates that there were 707 disasters every year during this period, reflecting an increase of about 60 percent over the previous years.
These natural disasters have domino effect on industrial facilities such as hazardous chemicals depots, gas and oil inventories, port terminals, power plants, transportation hubs for dangerous materials, and can trigger technology malfunctions resulting in the release of hazardous materials into the surrounding environment. The consequences of these ‘combination accidents’ are severe, causing immense damage to the public and the environment as a whole.
Disaster risk management is the sum total of all activities, programmes and measures that emphasize preparedness and mitigation, and can be taken up before, during and after a disaster with the purpose of averting and minimizing the resultant losses. Activities that are taken up within disaster risk management include:
It should be noted that the hazards in chemical industries are generally identified during the design stage by various methods for hazard identification, such as safety review, ‘checklist analysis’, ‘what-if analysis’, ‘fault tree analysis’ and the commonly-used technique of ‘Hazard and Operability studies (HAZOP)’. Based on the risk analysis of the identified hazards and considering design basis accidents, one can postulate the set of accidents and take measures to curb the incidence of these accidents in the design itself.
During hazard identification, due consideration should be given to postulated initiating events due to natural disasters (based on historical meteorological data, hydrological aspects, geology & geo-technological aspects, seismicity aspects), and the identified hazards should be mitigated through the adoption of safer engineering practices, improved safety devices and designing a fail-proof system.
The design-basis values for natural hazards such as earthquake, floods, cyclones, Tsunami etc. can be estimated for site-specific cases with historical data or determined through various national codes on the design of structures.
By considering the conservative design basis values for these natural hazards during site selection, the design stage and construction stage, the risk posed by the natural hazards can be reduced significantly. Safety design bases (SDB) developed on safety based concepts shall be adopted in all the stages of engineering safety-related civil engineering structures.
In the safety-based concept, possible design and operational events (both for normal and abnormal conditions) are first postulated. The engineering is then carried out to ensure that the structural system is reliable and is competent to withstand or mitigate the consequences of these postulated conditions, and is thereby capable of preventing disaster.
In spite of the advances made in knowledge and technology, failure-free design and devices have remained elusive. Even a well designed and inherently safe chemical facility must prepare to control potentially hazardous events that are caused by human or mechanical failure, or by natural forces such as floods or earthquakes.
An effective disaster risk management plan that integrates the potential chemical/industrial hazards with the integrated community emergency plan with respect to natural hazards is an urgent need. It is very important to understand the fundamentals of disaster and disaster risk management, in order to address the complex issue of potential combination accidents.
Disaster management in chemical process industries is an integral and essential part of a loss-prevention strategy. An effective disaster risk management plan, with an integrated approach that addresses combination accidents is an urgent need for a hazardous industry. A good communication system, training and understanding emergency procedures, regular interaction between government agencies and industries, and a high level of availability of emergency equipment are the key areas for effective disaster management.
The consequences of technological accidents triggered by natural disasters can be reduced adequately by detailed risk assessment, review of postulated initiating events during siting and design stages, and taking safety into consideration as an element of the overall design process— during the civil engineering design and construction stages.
