topic 3

10 Questions

Preventive safety measures can generally be grouped into 4 types. List these 4 types

implemented in the basic process control system human action physical protection system automatic safety system

which of these are example of human action under preventive safety measure

verification of safety critical steps

Explain how a safety shut down system can prevent the undesirable emission of flammable gases from a landfill when the outlet of the knock-out pot of the flare system is blocked.

liquid level increases and gets carried to the compressor

compressor gets damaged and release gas into the environment

high level switch can trip the compressor on high level to prevent loss event

Physical preventive safety measures such as relief devices are required to prevent over-pressurization in vessels. List the guidelines for specifying relief locations

all vessels, reactors, tower, storage tanks and drums
blocked in section of cool filled liquid line that are exposed to heat or refrigeration
positive displacement pump/turbines/compressors
storage vessels
vessel steam jacket
long process line that links to remote storage tank

list 3 mitigative safety measures

secondary containment fire mitigation emergency response reduction of loss during leaks/release

list the objectives of emergency response plan

safe guard people during emergencies
minimize damages to properties or equipment
contain incident and bring it under control
rescue and treatment of casualties
provide information to news media and public
secure safe rehabilitation of the affected area without more people being harm in the process
preserve records to investigate the cause to prevent reoccurring event.

What are the key components of an Emergency Response Plan (ERP)

emergency actions other than evacuation
escape procedure when necessary
esacpe route clearly marked on site map and road
method for accounting of people after evacuating
description and assignent of rescue nad medical duties
system to report emergency to proper regulatory agencies
mean of notification of people/public by alarm system
contact coordination and person responsibilities

describe pressure relief valve

adjustable spring tension that offsets the inlet pressure
set 10% above max normal operating range
adjustable screws cover with threaded caps to prevent unauthorize person from changing the relief valve set pressure

preventive safety measure is to interrupt the chain or events from happening after a deviation has happened and prevent a loss event

True

name 3 relief event scenarios

external fire
blocked outlet
overfill

Study Notes

Preventive Safety Measures

There are 4 types of preventive safety measures

Types of Preventive Safety Measures

Human action (e.g. operator error prevention, training, and procedures)
Physical preventive safety measures (e.g. relief devices, safety instrumentation)
Inherent safety measures (e.g. inherently safer design)
Procedural safety measures (e.g. maintenance, inspection, and testing)

Application of Preventive Safety Measures

A safety shut down system can prevent the undesirable emission of flammable gases from a landfill when the outlet of the knock-out pot of the flare system is blocked

Preventing Over-Pressurization

Physical preventive safety measures, such as relief devices, are required to prevent over-pressurization in vessels
Guidelines for specifying relief locations include:
- Identification of potential over-pressurization sources
- Determination of relief requirements
- Selection of relief devices
- Installation and maintenance of relief devices

Mitigative Safety Measures

These are measures taken after an incident to mitigate its effects
Examples of mitigative safety measures include:
- Emergency response planning
- Firefighting
- Evacuation procedures

Emergency Response Plan (ERP)

Objectives of an ERP include:
- Minimizing harm to people and the environment
- Reducing the impact of an incident
- Facilitating effective emergency response
Key components of an ERP include:
- Emergency response procedures
- Communication plans
- Training and drills

Pressure Relief Valve

A pressure relief valve is a type of relief device that automatically opens to release excess pressure and then closes when the pressure returns to a safe level

Preventive Safety Measure

A preventive safety measure is a measure taken to prevent a loss event or to interrupt the chain of events leading to a loss event

Relief Event Scenarios

Examples of relief event scenarios include:
- Over-pressurization of a vessel
- Rupture of a pipeline
- Failure of a critical safety device