Disaster Management Strategies A Look at Disaster Management Strategies for Chemical Process Industries

Author / Editor: H.K. Kulkarini, R. Bhattacharya / Marion Henig

Effective disaster management can go a long way in mitigating the damage caused by natural catastrophes, thereby increasing plant safety.

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Plants and factories must integrate disaster risk management into their design and operation to mitigate damages.
Plants and factories must integrate disaster risk management into their design and operation to mitigate damages.
(Picture: Shutterstock)

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.

In the Indian context, several instances of combination accidents have been witnessed. Some of these include the Gujarat cyclone in 1998 that affected industrial heart of Gujarat, the 1999 super cyclone that affected major industries in Orissa’s coastal belt and the major earthquake in Kutch, Gujarat, in the year 2001 that damaged the ports and major industries. In addition to these, India has also borne the brunt of the violent Tsunami waves that affected approximately 2,260 km of the country’s coast in Tamil Nadu, Andhra Pradesh, and the Andaman and Nicobar Islands, barely six years ago.

Floods Can Cause Disruptions

Fifty-nine percent of the land mass is susceptible to seismic hazard; five percent of the total geographical area is prone to floods and eight percent of the total landmass is prone to cyclones. The climatic changes witnessed in recent years contributed their own share of damages, triggering a spate of technological accidents such as an increase in the incidence of flooding due to changes in rainfall pattern and carrying capacities of rivers; and forest fires. Flooding causes severe disruptions in the environment by triggering the release of chemicals stored above the ground level and of toxic wastes from waste treatment plants, which, in turn, contaminate drinking water sources. Floods can also cause disruptions in the operations of sewage treatment facilities, and can trigger fires/explosions due to the loss of process control. Further, these disruptions can trigger reactions between hazardous and pyrophoric chemicals and flood water, electrical system mishaps and so on. In view of the increased probability of natural disasters triggering chemical disasters, as a conservative approach, it has become necessary to consider the same as the ‘worst-case scenario’ while preparing the disaster management plan for a particular plant site. This paper highlights the case study of a flood incident at a chemical plant located in the Surat-Hazira Industrial Belt in Gujarat, and the application of the disaster risk management plan. The plant falls under the purview of the Atomic Energy Regulatory Board (AERB). The safety issues that surfaced from the flood incident were reviewed in detail by AERB, and certain recommendations were made to improve the emergency response plan due to such incidents. The paper also highlights the significance of risk assessment techniques in the design stage, considering both natural and human–induced postulating events that may trigger such a disaster.

Disaster Management Cycle

Disaster risk management is the sum total of all activities, programmes and measures that emphasise preparedness and mitigation, and can be taken up before, during and after a disaster with the purpose of averting and minimising the resultant losses. Activities that are taken up within disaster risk management include:

  • Before a disaster (pre-disaster): Activities taken to reduce human and property losses caused by a potential hazard. These are mitigation and preparedness activities.
  • During a disaster (disaster occurrence): Initiatives taken to ensure that the needs and provisions of victims are met, and their suffering minimised. These are emergency response activities.
  • After a disaster (post-disaster): Initiatives taken in response to a disaster with the purpose of achieving early recovery and rehabilitation of the affected communities, immediately after a disaster strikes.

Decoding Disasters and Disaster Risk Management

A disaster is a catastrophe, mishap, calamity or grave occurrence in any area, arising from natural or man-made causes, or by accident or negligence, which results in a substantial loss of life or human suffering or damage to, and destruction of, property, or damage to, or degradation of, the environment.

An event is only categorised as a disaster when its nature or magnitude is beyond the coping capacity of the community of the affected area. A disaster is the result produced from the combination of a hazard, vulnerability and insufficient capacity or measures to reduce the potential chances of risk.

Simply put, disasters occur only when hazards and vulnerability meet.

Case Study: Averting a Naturemade Catastrophe

The chemical plant described here is located on the bank of River Tapi, at a distance of about 15 km from Surat city. The plant is located within the fertiliser complex. It handles large quantities of ammonia, synthesis gas and potassium amide at very high pressures and temperatures. The plant also has in its inventory, small quantities of hazardous materials such as hexane, potassium metal, natural gas/naphtha and various industrial chemicals. Some of the chemicals such as potassium amide and potassium metal react violently when they come in contact with water. The river Tapi originates from Betul in the Satpura Hills of Madhya Pradesh, and flows through Maharashtra and Gujarat. A dam was constructed at Ukai, which is 80 km upstream of the Surat–Hazira industrial belt, with the sole aim of avoiding flooding. It has been noticed that the water-carrying capacity of the Tapi river has reduced considerably over the years; the reason is the continuous deposition of topsoil and sewage. The frequency of floods in Surat city has increased due to the reduced water discharge capacity of the river (upto 5 lakh cu secs).

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On August 7, 2006, the neighbouring villages and the Hazira industrial belt were faced with the likelihood of a flooding disaster on account of the release of large quantities of water from the Ukai dam. The release of water continued until the plant and the neighbouring villages remained submerged in 5 to 6 feet of water, for four days. The basis flood level that was considered during the plant design was based on historical data of the highest flood level—around 1 ft. However, this figure only reflected the highest flood level the plant had experienced to date.

The plant personnel had received notification about an impending huge release of water from the Ukai dam into the Tapi river in the morning of the day of the incident, and communication had been established between the plant, district collector office and Ukai dam authorities. Based on the information received by the Ukai dam authorities about the release of water from the dam, the decision to stop the operations of the plant was taken to keep water from entering the plant premises. However, at 11:20 pm, the plant tripped due to electrical supply failure (due to the ingress of floodwater into the substation).

The Shutdown Activities Were Completed by Midnight

The shutdown activities were completed by midnight. At 01:30 am, a shift engineer observed that floodwater had entered into plant area through the storm water drains. Officials were also informed that water would enter the residential colony, which was at a 7-ft elevation, by the afternoon of August 8, 2009. By the next day, the water level in the plant premises was significantly high and remained that way for the next three days, owing to the continuous discharge of water from the dam at a rate greater than 11 cu secs for the next three days. The communication system, including mobile phones, failed totally. The plant personnel were stranded at their respective places in the plant, as there was no facility to move through the floodwater. There was absolutely no communication, both within the plant and outside.

Actions Initiated by Plant Personnel

The detailed activities with respect to the flood and the potential chemical disaster management that were carried out by the plant are mentioned below:

Activities done during pre-disaster (i.e. before the ingress of flood water into plant

premises):

In view of the information it had received about the release of water from the Ukai dam, the plant had carried out certain mitigation and preparedness activities to reduce the human and property losses. It was ensured that adequate manpower was available to essay the safe shutdown of the plant. The personnel are located at safe elevations in the control room after carrying out the required shutdown activities.

  • The hazardous chemicals, which could react violently when in contact with water, were shifted to higher elevations.
  • The trip logic shutdown system for process control and safe start-up and shutdown were initiated to ensure safe shutdowns of the plant in the ‘Auto’ mode.
  • Two emergency lights were kept charged and ready for use.
  • Arrangements were made for food packets, drinking water etc. for the shift personnel.
  • Adequate isolation-valve handles were provided to the field operators for closing certain isolation valves in the case of an emergency.
  • Breathing air apparatus and fire extinguishers were kept in the control room and the fire station at higher elevations.
  • The communication system was checked and deficiencies rectified.
  • The rotating equipment tripped due to electrical supply failure and diesel generator sets started on auto ‘mode’ for providing electrical power to safety-related critical equipment were verified.
  • The isolation of high-pressure loops (HP) from low-pressure loops (LP) was done through the programme matrix logic, monitored through the distributed control system (DCS) with the available, uninterrupted power supply (UPS). The loops were also kept pressurised by synthesis gas, as per the standard operating procedure (SOP).
  • Shutdown of crackers (for cracking ammonia gas into synthesis gas) was done as per SOP and cooling was completed.
  • Battery-limit isolation valves of natural gas line, steam, etc. were isolated manually.
  • The UPS supply to field control panels, electrical supply to MCC panels and the diesel generator power supply was cut off, and the diesel-driven firewater pump was stopped.

During a disaster (i.e. after the flood water entered the plant premises):

There were certain lapses with respect to the emergency response activities, such as:

  • There was total failure of the communications system, both within and outside the plant premises.
  • Due to the rise in the water level, there was no mobility of plant personnel and other rescue teams
  • The food supply to the personnel stationed on first floor of control room was hindered due to flood-water level and the emergence of large numbers of venomous reptiles.
  • There was no drinking water supply.
  • Muddy water had entered the ground floor of the control room.

Post flood scenario:

The floodwater started receding after three days. The senior plant personnel could finally enter the plant premises and the shift personnel who were inside the plant for three days could be relieved from their duties. There were no casualties due to the flood disaster; however, there was loss of property due to damage of equipment such as pump motors, diesel generator sets and the Distributed Control System (DCS) bus isolation card. The motors were decoupled, cleaned thoroughly, applied with a thick varnish coat and the bearings replaced. The DCS electronic cards were cleaned, dried thoroughly and reinstalled. Certain activities were done as top priorities to restore the supply of drinking water, electricity and establish communication systems for the plant and residential colony. The instrument loop and trip logic simulation test was done to check for instrumentation communication and functioning as per design intent.

How Careful Planning Helped in Averting a Disaster

AERB carried out a review of the abovementioned significant event, both from the disaster management perspective and the safety aspect, after restoration and restarting of the plant. It was observed that due to real time information from the Ukai dam officials, the availability of documented standard operating procedures to handle plant emergencies and the involvement of trained and experienced manpower, the plant was safely shutdown before the entry of floodwater within the premises.

The pre-planning ensured that the hazardous chemicals and critical equipment were shifted to higher elevations, thereby preventing any combination accident. Certain safety issues related to the emergency response activities were observed, with respect to preparedness and mitigation during the flood. It was noted that a flood incident had occurred in this Hazira Surat industrial site in 1998. In view of the increased frequency of flooding, AERB recommended certain measures for improving disaster risk management due to flood hazards. Some of the significant recommendations are mentioned below.

  • Procurement and maintaining two numbers of motor operated boats in the Fire and Safety department, for effective and efficient rescue of plant and residential township personnel during flood situations.
  • The control room should be equipped with life jackets/air bags to ensure plant safety by timely shut down of the plant and rescuing the control room personnel.
  • Openings should be made at suitable locations in the Control Room for draining the stagnated floodwater from the cable trenches.
  • Portable diesel-operated pumps should be made available for dewatering the floodwater.
  • The control room should be provided with proper access to the roof top for shifting personnel to safer location in case the flood water level rises to more than 6 ft.
  • Adequate emergency searchlights should be made available (at least four numbers) for proper mobility in the plant area in case of a total black out (no electrical power supply from any means).
  • The plant should ensure availability of portable diesel generator sets of suitable rating to recharging walkie talkie (wireless communication sets) sets and portable illumination devices during such emergencies.
  • The plant should explore the possibility of constructing a storeroom above the fire station control room for storing the emergency and life-saving equipment during such incidents.
  • A water tank with capacity of 5,000 litres should be installed for catering to the drinking water requirements of plant and the residential personnel.
  • The height of the dyke wall of the fire pump house should be raised, keeping the reference of highest flood-level in the plant area.

It was recommended to mark the ‘Reference Flood Level’ of the plant site (based on the recent flood incident) for initiating planned safe shutdown of the plant. The marked flood level is now documented in the site emergency preparedness plan and the technical specifications for the operation of the plant.

A disaster management plan for flood emergency has been prepared by the fertiliser unit, clearly defining the precautions to be observed in case of a flood emergency, major actions to be taken during flood emergency and after the flood emergency by various departments in plants such as the Personnel & Administration department, Medical department, Production department, Mechanical, Electrical, Instrumentation, Civil, Fire & Safety, and Laboratory & Materials departments.

The document clearly defines the role of each department before the flood incident, during the flood incident and after the flood incident. The plant has implemented the recommendations and, with the thoughtfully- prepared disaster management plan, it is prepared to mitigate any challenge stemming from flood hazards.

Risk Assessment and Disaster Management

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 designbasis 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 safetybased 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 welldesigned 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.

Understand the Fundamentals

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 Risk Management Is Vital for Process Industries

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.

* The authors are members of the Atomic Energy Regulatory Board (AERB), Industrial Plants Safety Division, Anushaktinagar.

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