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DRPS : Course Catalogue : School of Engineering : Chemical

Undergraduate Course: Process Safety 4 (CHEE10006)

Course Outline
SchoolSchool of Engineering CollegeCollege of Science and Engineering
Credit level (Normal year taken)SCQF Level 10 (Year 4 Undergraduate) AvailabilityAvailable to all students
SCQF Credits10 ECTS Credits5
SummaryThis course introduces the principles of loss prevention and presents methods of quantitative risk assessment and consequence analysis. Methods which are amenable to hand calculation are emphasised, rather than more complex modelling methods. The legislative framework for safety in the UK, particularly with reference to the chemical and process industries, is outlined.
Course description Self-study questions
Post exam script viewing
Online discussion
Feedback given on general exam performance (made available after the exam to current and subsequent cohorts)

This course comprises 18 lectures with additional self-studied material. Case studies of significant historical incidents will be introduced where they contribute to the material of the course.


Topic 1. Introduction. Overview of process safety. Problems of complexity. Principles of Inherent safety. Layers of Protection concept.

Topic 2. Uk and European Safety Legislation. Historical background. HASAWA, regulations, role of HSC and HSE. European legislative framework.

Topic 3. The Concept of risk. Definitions of risk and
hazard. Acceptability of risk. Perception of Risk. Quantification of risk. Cost-benefit analysis. Fatal accident rate. ALARP.

Topic 4. Probability and Frequency for Risk Assessment. Basic probability calculations. Frequency and duration of coincident events.

Topic 5. Reliability. Definitions. Failure distributions. Reliability with multiple components. Active and passive failure. Trip reliability. Fractional dead time. Multiple channel trip systems.

Topic 6. Fault Trees. Construction of fault trees. Finding minimum cut sets.

Topic 7. Event Trees. Construction of event trees. Bow-Tie analysis. Buncefield accident and learning points.

Topic 8. Hazard Identification. Predictive vs. experience based hazard identification. Checklists and codes of practice. HAZOP methodology. Dow and Mond Indices.

Topic 9. Occupational Health. Damaging agents. Harmful substances. Assimilation routes. Exposure limits. Toxicology, epidemiology, other methods for establishing exposure limits. COSHH. Exposure control.

Topic 10. Source terms. Leak rates for liquids and gases. Evaporation rates from spills and jets.

Topic 11. Fire. Flammability limits, flash point, sources of ignition. Types of fire. Diffusion and pre-mixed flames. Damaging effects. Flame size. Radiation estimation. Boilover. Area Classification.

Topic 12. Explosions. Types of explosion. Damaging effects. TNT method for overpressure estimation. BLEVE. Dust Explosions.

Topic 13. Human Error. Human error rates. Types of error. Performance levels. Reducing human error.

Topic 14. Safety Management Systems. Hazards of operation and maintenance. Permit to work systems. Preparation of plant for maintenance.

Topic 15. Safety for Design. Specific advice on safety considerations for design projects.

Self-study questions

1. Fatal accident rate, probability of multiple events, cost-benefit analysis.
2. Reliability
3. Probit
4. Fault trees, event trees and bow-tie diagrams
5. Fires
6. Explosions
7. Source terms

Other Teaching Events

Self-Study topics:
Use of Probit functions (revision of previous work using handout and references)
Dust explosions - CSB Video supplementing lecture material - online
Boilover - self study material provided via the web.
Environmental health - additional notes provided for self-study.
Safe Working Systems - additional notes provided for self-study.

Online discussion: Qualitative questions will be set for online discussion and formative feedback.

Entry Requirements (not applicable to Visiting Students)
Pre-requisites Students MUST have passed: Chemical Engineering Design 3 (CHEE09015)
Prohibited Combinations Other requirements None
Information for Visiting Students
High Demand Course? Yes
Course Delivery Information
Not being delivered
Learning Outcomes
On completion of this course, the student will be able to:
  1. Understand the legal framework for process safety in the UK and elsewhere.
  2. Appreciate how acceptability of risk is established in process safety.
  3. Use relevant techniques to estimate the risk resulting from processes.
  4. Use basic models to predict the consequences of process accidents.
  5. Be familiar with safety management methods used to control risk in process plant operation.
Reading List
1. Process Safety Analysis - an Introduction, Bob Skelton (IChemE, 1997).

2. Major Hazards and their Management, Geoff Wells (IChemE, 1997).

3. Lees' Loss Prevention in the Process Industries 2nd Ed in Library, 3rd Ed available electronically via the Library.
Additional Information
Graduate Attributes and Skills Not entered
KeywordsNot entered
Course organiserDr Jennifer Skilling
Tel: (0131 6)50 4863
Course secretaryMrs Shona Barnet
Tel: (0131 6)51 7715
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