The Swiss Cheese Model

 A session titled “Suraksha Saunskruti: Safety for You” — a step forward in reinforcing our safety-first culture

Thanks to Facilitator: Mr. Amresh Deshmukh Sir (Vice President – HSE)

 The Swiss Cheese Model, developed by James Reason, is a visual tool used in risk management and accident analysis. It represents how multiple layers of defense (like slices of Swiss cheese) can prevent incidents from occurring. When holes in these layers align, it can lead to an accident. Prevention, detection, control, and mitigation are all addressed within this model as different layers of defense. 

Prevention: Preventative measures are the layers of defense that aim to stop hazards from ever becoming a threat. This includes things like robust design, thorough training, and implementing safety protocols. For example, in software development, preventative measures might include code reviews, secure coding practices, and vulnerability scanning. 

Detection: Detection layers identify when a hazard or error has occurred, even if it wasn't prevented. This could involve monitoring systems, audits, or checklists. In the context of software, intrusion detection systems, security audits, and error logging are examples of detection mechanisms. 

Control: Control measures are put in place to limit the impact of a hazard or error once it has been detected. This might involve access controls, firewalls, or emergency response procedures. For example, in a chemical plant, control measures could include safety shut-off valves or emergency containment systems. 

Mitigation: Mitigation strategies aim to reduce the severity of an incident after it has occurred. This might involve disaster recovery plans, backup systems, or post-incident investigations. In software, mitigation could involve data backups, failover systems, or incident response plans. 

In essence, the Swiss Cheese Model highlights that a combination of preventative, detective, control, and mitigation measures is necessary to create a resilient system that can withstand multiple potential failures. By identifying and addressing weaknesses in each layer, organizations can reduce the likelihood of accidents and improve overall safety. 

Integrity Barrier

Safety and Environmental Critical Elements

Structural Integrity 

Foundation Structures

Surface Structures

Heavy Lift Cranes

Occupied Buildings

Process Containment 

Pressure vessels

Heat Exchangers

Rotating Equipment

Tanks and Piping Systems

Bunding and Drainage

Tanker Loading

Ignition Control 

Hazardous Area Ventilation

Non-Hazardous Area Ventilation

Certified Electrical Equipment

Tripping of non-certified Equipment

Inert Gas Systems

Earth Bonding

Hot surface management

Spark Arrestors and Flame and Flashback arrestors

  Protection Systems 

Passive and Active fire Protection Systems

Layout and segregation

Explosion Protection

Firewater Pumps

 

Detection Systems

Fire & Gas detection

Corrosion monitoring equipment

Flaring monitoring equipment

Shutdown Systems (Isolation and Blowdown) 

ESD including IPF and HIPPS

Depressurisation

Equipment Isolation

Piping isolation

Valves

ESDV

Emergency response 

Protection Systems as above

Escape and Evacuation Routes

Emergency/Escape Lighting

Communication Systems

UPS

Open Haz/Non-Haz Drains

Emergency Power

Medical Emergency response times

Spill kits

 Lifesaving 

Personal Safety Equipment

Tertiary means of Escape

The Swiss Cheese Model, applied to Swiggy's safety protocols, suggests that accidents or incidents are less likely to occur when multiple layers of safety defenses are in place. These layers, like slices of Swiss cheese, each have potential weaknesses (holes). When these holes momentarily align, a hazard can pass through, leading to an incident. Swiggy uses this model to identify potential vulnerabilities in their delivery system and implement multiple, overlapping safety measures to prevent accidents. 

Understanding the Swiss Cheese Model

Multiple Layers of Defense:

The model visualizes safety systems as a series of layered defenses, similar to slices of Swiss cheese stacked together.

Holes as Weaknesses:

Each layer has potential weaknesses or "holes," representing potential failure points in the system.

Alignment of Holes:

Accidents occur when these holes align across multiple layers, allowing a hazard to pass through and cause an incident. 

Applying the Model to Swiggy

Swiggy's safety protocols likely incorporate various layers of defense, such as: 

Driver Training: Training on traffic rules, defensive driving, and food safety.

Vehicle Safety Checks: Regular maintenance and safety checks on delivery vehicles.

Delivery Route Optimization: Using technology to optimize routes and minimize travel time in high-risk areas.

Emergency Response Systems: Implementing procedures for handling accidents or emergencies, including communication with emergency services.

Rider Feedback Mechanisms: Creating channels for riders to report unsafe conditions or incidents.

Real-time Tracking and Monitoring: Using GPS and other technologies to track rider location and speed, allowing for intervention if needed.

Preventing Accidents through the Model

By understanding the Swiss Cheese Model, Swiggy can: 

1. Identify Potential Weaknesses:

Analyze each layer of their safety system to identify potential weaknesses or "holes."

2. Strengthen Defenses:

Implement measures to strengthen each layer and reduce the likelihood of holes aligning.

3. Reduce Risk:

By having multiple, overlapping defenses, the chances of a hazard passing through all layers and causing an accident are significantly reduced.

Example:

Imagine a delivery driver speeding.

Layer 1: Training:

If the driver has not been properly trained on speed limits, this layer has a hole.

Layer 2: Real-time Tracking:

If the system isn't monitoring speed in real-time, this layer also has a hole.

Layer 3: Emergency Response:

If there is a delay in contacting emergency services after an accident, this layer also has a hole.

When these holes align, the speeding driver might be involved in an accident with severe consequences. Swiggy's goal is to ensure that even if one layer has a hole, other layers will prevent the accident from happening.