Assessment Task 3 – Quantitative Risk Assessment and Decision Making Part A

Introduction

For a person from Tianjin, the Tianjin Port explosion was a very serious engineering incident. On 12 August 2015, a fire occurred in a warehouse building in Tianjin Port because hazardous chemicals were not properly stored. Because of this event, two huge explosions occurred, causing many deaths, massive property damage, and environmental degradation.

The purpose of this paper is to use the Tianjin Port explosion as an example to understand the main factors that led to the disaster and to discuss how to prevent similar mistakes from happening again.

1.Case study overview

1.1 Incident Loss

As a result of the accident, 165 people were killed, 8 people were missing, 798 people were injured; 304 buildings, 12,428 commercial vehicles and 7,533 containers were damaged. Direct economic losses 6,866 million RMB. － Ministry of Emergency Management of People’s Republic of China investigation

report, 2015.

1.2 Summary of the incident

At around 23:34 on August 12, 2015, there was a series of explosions of flammable and explosive products in containers at the container terminal of the Ruihai International Logistics Center in Tianjin Port, Binhai New Area, Tianjin City.

The direct cause of the dangerous goods container nitrocellulose local drying, under the action of high temperature and other factors to accelerate the decomposition of exothermic, spontaneous combustion of heat accumulation, and finally to other hazardous chemicals such as ammonium nitrate and other hazardous chemicals to explode!

1.3 The timeline of the event

The initial fire occurred at 22:51:46 on August 12, 2015, and initially started in the middle of the container area on the south side of the arrivals area of Ruihai's hazardous materials warehouse. The weather was dry and hot at the time of the incident, which led to the decomposition of nitrocellulose cotton in the dangerous goods containers and the spontaneous combustion of the accumulated heat.

At 22:52 on the night of the accident, the 110 Command Center of Tianjin Public Security Bureau received an alarm that a fire had occurred in the dangerous goods stack of Ruihai Logistics of Tianjin Binhai New Area Port Group and referred the alarm to the Fire Brigade of Tianjin Port Public Security Bureau.

Then the Tianjin Port Public Security Bureau Fire Brigade immediately dispatched the Tianjin Port Fire Brigade No. 4, which is the closest to Ruihai Company, to rush to the scene.

At 22:56, Tianjin Port Public Security Bureau Fire Brigade No. 4 arrived at the scene first. The commander of the scene requested the Tianjin Port Public Security Bureau Fire Brigade for reinforcement.

At 23:08 , 6 active public security squadrons of Tianjin Fire Brigade and 3 full-time fire brigades of Tianjin Port, with 36 fire engines and 200 people, participated in fire-fighting and rescue. Meanwhile, more firefighters are still on their way.

At about 23:34 , two strong explosions occurred at the fire. The first explosion occurred at 23:34:06. The Ministry of Emergency Management of People’s Republic of China investigation report attributed the cause of the first explosion to the high temperature of the nitrocellulose combustion leading to the decomposition and explosion of the surrounding ammonium nitrate, with an explosive equivalent of 15 tons of TNT.

At 23:34:37, the fire scene occurred a larger second explosion, Ministry of Emergency Management of People’s Republic of China investigation report said the second explosion equivalent to 430 tons of TNT.

The explosion, which raised smoke and dust up to tens of meters high at the time, caused 12 firefighters to die and 36 firefighters to be lost. 30 fire engines were destroyed in the accident.

The two explosions formed a small crescent-shaped crater 15 meters in diameter and 1.1 meters deep, and a large circular crater 97 meters in diameter and 2.7 meters deep, with an average of more than 40 times the toxic substances in the crater, and more than 800 times the sodium cyanide.

1.5 Setting Clear Boundaries

1.5.1 Boundaries in Time

Start Date: The study starts on August 12, 2015, the day of the explosion. It looks at things that happened before the disaster, like how the dangerous materials were stored and handled.

End Date: The study will look at what happened after the explosion, including the first responses and results of the investigation,  all the way through to the end of 2015.

1.5.2 Boundaries of Geography

The main focus will be on the Ruihai International Logistics Company's warehouse for dangerous goods at the Tianjin Port, which is where the blast happened.

Secondary Locations: The study will also look at the larger Tianjin Port area, as well as the communities and structures that were touched by explosion in the area around it.

1.5.3 Technology and Systems

Hazardous Material Storage and Management System: This includes the places to store chemicals, the ways to handle them, and the people who are in charge of all of these things.

Firefighting and Emergency Response Systems: It is about what to do right after an explosion, including what firefighting gear to use and what to do in an emergency.

Urban planning and safety design: This includes the planning of space and safety issues that come up when putting dangerous goods stores close to residential and business areas.

1.5.4 Limits in Social and Economic Life

Direct Effects: The study will look at the direct effects on people who are close by, such as warehouse workers, first responders, locals, and business owners in the affected area.

Indirect Effects: The bigger economic effects on Tianjin City and the country's economy will also be looked at, along with the long-term effects on safety rules and standards in China's chemical industry.

2.Sub-systems, components/equipment, RBD

2.1Hazardous Material Storage and Management System

2.1.1 Description

The primary function of this system is to ensure the secure storage and effective management of dangerous substances inside the warehouse located at Tianjin Port.

2.1.2 components/equipment

1.Storage Facilities:  Equipment specially designed for the safe storage of hazardous substances such as ammonium nitrate and nitrocellulose; temperature and humidity monitoring systems for the storage environment; cameras that are switched on twenty-four hours a day.

2.The handling procedures:  Procedures for handling hazardous chemicals established by company professionals; laws and regulations established by government departments.

3.Management Oversight:  The company needs to develop administrative control and management procedures to ensure that warehouses comply with safety standards, frequent inspections and training of personnel responsible for handling hazardous substances.

2.2 Firefighting and Emergency Response Systems

2.2.1 Description

This system encompasses the equipment, protocols, and response measures in place to address emergencies such as fires or explosions.

2.2.2 components/equipment

1.Firefighting Equipment: Appliances and systems, including fire extinguishers, sprinkler systems, and fire engines, that are used to battle fires.

2. Emergency Protocols: Implemented set of processes for addressing crises, including evacuation strategies, communication channels, and collaboration among various emergency response teams.

2.3Urban Planning and Safety Design

2.3.1Description

It refers to the systematic analysis of the spatial organisation and design factors associated with the positioning of facilities for storing hazardous materials.

2.3.2 components/equipment

1.Location of the warehouse

Proximity to Residential Areas: Ensuring that hazardous materials warehouses are located at a safe distance from residential and densely populated areas to minimize the risk to human life in case of an accident.

Industrial Zoning: Proper zoning laws and regulations that govern where such hazardous facilities can be located, considering factors like wind direction, access to emergency services, and transportation routes.

2.Safety Design Considerations: Incorporating safety features such as blast walls, separation distances between storage units, and controlled access to hazardous areas.

3.Implementation and results

3.1 FTA（Fault tree analysis）

3.1.1 Top Event:Tianjin Port Explosion Incident

This is the ultimate top event, referring to the fire and subsequent two large explosions in the warehouse.

3.1.2First-Level Causes

1.Improper Storage of Hazardous Chemicals

2.Unfavorable Environmental Conditions

3.Insufficient Emergency Response

3.1.3 Second-Level Causes

Analysis of the First-Level Causes leads to the Second-Level Causes

1.Improper Storage of Hazardous Chemicals

A. highly hazardous chemical:Stored highly dangerous chemicals like nitrocellulose and ammonium nitrate.

B.Improper storage:Failure to follow safety regulations and standards for chemical storage, leading to inadequate spacing between dangerous goods.

2.Unfavorable Environmental Conditions

A.High Temperature:High temperatures caused the spontaneous combustion of nitrocellulose.

B.Dry Climate:Dry climate accelerated the decomposition and self-combustion of chemicals.

3.Insufficient Emergency Response

A.Firefighters Unaware:Firefighters were unaware of the types and quantities of chemicals stored at the site.

B.Inappropriate Firefighting Measures:Using water to extinguish the fire, which reacted with ammonium nitrate, triggering a larger explosion.

3.1.4. Third-Level Causes

Further analysis of some causes leads to Third-Level Causes

1.Improper storage

A.Poor Warehouse Management:Poor management practices at Ruihai International Logistics Company, failing to enforce safety inspections.

B.Lack of Supervision:Lack of oversight by Tianjin Transportation Commission, allowing the storage of hazardous chemicals without proper qualifications.

2.Inappropriate Firefighting Measures

A.Lack of Professional Training:Emergency personnel lacked professional training to handle chemical fires.

B.Lack of Proper Equipment:Tianjin Port and Ruihai International Logistics lacked specialized firefighting equipment for chemical fires.

3.1.5 Root Causes

1.Management and Human Errors:Management at Ruihai International Logistics failed to follow safety protocols, and employees lacked sufficient professional training.

2.Lack of Government Supervision:Local government and regulatory bodies failed to adequately supervise the company's safety management.

3.1.6 Model

3.2 ETA(Event Tree Analysis)

3.2.1 event identification

1. lack of management

2.Lack of training of workers

3.Rough handling of nitrocellulose

4.Destorying the packaging

5.Catching fire

6.illegal storage

7.obstructed fire engine access

8.Not extinguishing the fire properly and timely

9.Igniting ammonium nitrate and other substances

10.Occurrence of multiple explosions

3.2.3 Time flow analysis

3.2.3  Model

3.3 BT (Bayes Tree)

3.3.1 BT and FTA

3.3.2 BT and ETA