MKH 1223

Part 1 – Introduction to Process Safety

Topics Notes to Download
1.1 Introduction to Process Safety 

Process Safety generally refers to the prevention of unintentional releases of chemicals, energy, or other potentially dangerous materials (including steam) during the course of chemical processes that can have a serious effect to the plant and environment..

  • In memories
  • Process Hazards
  • Risk Assessment & Risk Ranking
  • Inherent Safety
1.1 Introduction to Process_Safety
1.2 Plant Operation System 

  • Hardware system
  • Distributed Control System
  • Layer of Protection
1.2 Plant Operation System
1.3 Process Diagrams 

  • Block Diagram
  • Process Flow Diagram
  • Piping & Instrumentation Diagram
1.3 Process Diagrams 

(P&ID – ISA)

1.3b_pid_symbol_din (P&ID – DIN Standard)

1.4 Process Safety Management 

Process Safety Management is a regulation, promulgated by the U.S. Occupational Safety and Health Administration (OSHA). A process is any activity or combination of activities including any use, storage, manufacturing, handling or the on-site movement of Highly Hazardous Chemicals (HHCs) as defined by OSHA and the U.S. Environmental Protection Agency.

1.4 Process Safety Management 

Part 2 – Process Hazard Analysis

Topics Notes to Download
2.1 Introduction to Process Hazard Analysis 

Process Hazard Analysis (PHA) is a set of organized and systematic assessments of the potential hazards associated with an industrial process. A PHA provides information intended to assist managers and employees in making decisions for improving safety and reducing the consequences of unwanted or unplanned releases of hazardous chemicals. A PHA is directed toward analyzing potential causes and consequences of fires, explosions, releases of toxic or flammable chemicals and major spills of hazardous chemicals, and it focuses on equipment, instrumentation, utilities, human actions, and external factors that might impact the process.

2.1 Introduction to PHA
2.2 Hazard and Operability (HAZOP) Study 

HAZOP is a structured and systematic examination of a planned or existing process or operation in order to identify and evaluate problems that may represent risks to personnel or equipment, or prevent efficient operation.  It is  a qualitative technique based on guide-words and is carried out by a multi-disciplinary team (HAZOP team) during a set of meetings.

2.3 Layer of Protection Analysis ( LOPA) 

LOPA is a semi-quantitative PHA methodology that can be conveniently applied following a HAZOP study but prior to Fault Tree Analysis. LOPA focuses the risk reduction efforts toward the impact events with the highest risks.  It provides a rational basis to allocate risk reduction resources efficiently.


2.3 LOPA

2.4 Safety Integrity Level (SIL) 

SIL is defined as a relative level of risk-reduction provided by a safety function, or to specify a target level of risk reduction. In simple terms, SIL is a measurement of performance required for a Safety Instrumented Function (SIF)


2.4 SIL

2.5 Fault Tree Analysis 

Fault Tree is a method by which a particular undesired system failure mode can be expressed in terms of component failure modes and operator actions. The system failure mode to be considered is termed the “top event” and fault tree is developed in branches below this event showing it causes.

2.5 Fault-Tree Analysis (FTA)
2.6 Event Tree Analysis 

Event tree analysis (ETA) is an inductive procedure that shows all possible outcomes resulting from an accidental (initiating) event, taking into account whether installed safety barriers are functioning or not, and additional events and factors.

By studying all relevant accidental events (that have been identified by a preliminary hazard analysis, a HAZOP, or some other technique), the ETA can be used to identify all potential accident scenarios and sequences in a complex system.

2.6 Event Tree Analysis (ETA)

Part 3. Consequence Modelling

Topics Notes to Download
3.1 Source Model 

Source models deal with the rate of release of materials from its source following a leakage or rupture. Typically, basic governing equations from momentum balances are used.

3.2 Dispersion Model 

Dispersion models estimate the dispersion of materials from the source. It is influenced by weather conditions as well as the terrain of the surrounding areas.

  • Mass Dispersion (Neural Buoyant)
  • Mass Dispersion (Pasquill-Gifford)
  • Simultaneous Heat and Mass Transfer
  • Heat Dispersion  (Radiation Heat Transfer)


3.2c Heat Dispersion

3.3 Fire  

Fire Models estimate the dimensions of fire based on its type.

  • Flash Fire
  • Jet Fire
  • Pool Fire
3.3_Fire and Explosion Model
3.4 Explosion 

Explosion models predict the coverage on an explosion which can then be used to predict the extent of damage.

  • VCE
  • Physical Explosion
  • Chemical Explosion
3.5 Aloha Software 

It is part of CAMEO and is useful in modelling dispersion and explosion

The Software can be downloaded from:

EPA and the National Oceanic and Atmospheric Administration (NOAA) developed this web site to facilitate the use of CAMEO and to offer online technical support. Please visit periodically for the latest news, information, and resources.

3.5b ALOHA’s Manual
3.6 Probit Analysis 

Probit analysis is a simple way to estimate fatality due to toxic release as well as fire and explosion.

Part 4 – Quantitative Risk Assessment

Topics Notes to Download
4.1 Introduction to QRA
3.2 QRA Procedure 

3.3 Case Study  

5. Design for Safety

– Inherent Safety

– Fire and Explosion Prevention

– Design of Relief System


Assignment Group Deliverable Due Date
1. Deepwater Horizon KL and JB Oral presentation, softcopy of materials past

HAZOP Problem for KL Group

KL Oral presentation and written report 5 Sept 2010


JB Oral presentation and written report 6 sept 2010
4. QRA


KL Written Report Final exam
5. QRA


JB Oral presentation and written report 25 oct 2010

2 responses to “MKH 1223

  1. hi prof.
    the Event tree doc is not available for me to download,received a message that the file is broken!
    could you please upload it again or fix the problem?

    thank you in advance


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s