Consequence assessment tool - how significant for risk assessment

There are a number of tools and techniques available for process hazards consequence assessment which includes models for manual use and computer codes. Many of the software programs use the Gaussian dispersion or similar algorithms to evaluate gas dispersion. These tools are often developed in order to assess a particular application (passive gas, dense gas, or specific chemical); some of them are further developed and modified to extend the range of usability.

Mostly, commercially marketed software models are validated using experimental field test, but often the results are far from the real scenarios experienced. The main reason being the limited range of application; in most process hazard cases, the materials involved are not a single, pure material and the effects of obstructions close to the release or incident site are not included in the model.

In general, for consequence assessment, using software tools some of the challenges are:
- Modelling the effects of multi-component material with varying physical & chemical properties
- Incorporating the effects of terrain, barriers, slops, structures and buildings
- Changes in weather condition during the release
- Near and far field effects

In order to overcome these challenges, the computational fluid dynamics technique which uses the physical formula was considered as an alternative to more conventional models. This paper looks into the modelling of dispersion characteristics using computational fluid dynamics around a built up area of a chemical plant and compares the results obtained using Gaussian algorithm. This is based on a consequence assessment study performed for a loss of containment event within a tank bund.

The CFD tool used is fluidyn-PANEPR and the tool used with gas dispersion algorithm is DNV PHAST.


The poster based on the above abstract was shown for ChemEng08 and is viewable from the following link:
http://myaker.net/_upl/icheme_poster_sreeraj.pdf

Acknowledgements: To co-author/contributor Mr.Ken Norrie

Risk perception

The term ‘risk’ is a term used quite often and in day to day life. Risk is defined and represented in different ways based on the associated activity and its nature. Risk consists of a combination of the probability of a perceived threat or opportunity occurring and the magnitude of its impact on objectives.

In process and manufacturing industries (not exclusive), most commonly, risk is assessed, analysed and expressed in terms of individual risk and societal risk. The risk estimation and analysis is to ensure that the risk an industrial activity is not resulting in intolerable levels.

Risk is perceived in terms of the severity from an event and its frequency. The fact to be noted is that those events with minimal severity but frequent posses similar risk to those events with maximum severity but not that frequent. The everyday activities like smoking (including passive) and driving (including being on road or on a means of transport) also could result in fatality and keep public at higher risk. These events may not be often classified as severe but happen quite frequently.

Then there are near-to-known or unknown treats like dust explosions and exposure to asbestos. The risk from such activities is seldom assessed due to lack of knowledge on the potential consequence. This raises the question on perceiving risk from potential major incidents. Even though the severity is estimated and well understood, it is often neglected considering as not likely.

An example: Catastrophic failure of a hazardous material storage tank could result in multiple fatalities and the recorded failure frequency is one in a million years (1 x 10-6 /yr). There are more than a million tanks which could result in similar catastrophe; which means, there will be a catastrophic failure of tank every year. The tank could be the tank on your way to work, which supply the fuel to the garage from where you re-fill, the site where you or dear one works, the near to school or hospital. And this is happening, yes every year there is a major incident associated with storage tanks.

Terrorism - Risk and Evaluation

Mumbai 30/11/08: Enough and more has happened in the last few days from the coward act of few men; what ever their aims where. The gun rattilage has resulted in 200 fatalities and more than 300 injured and thousands affected (directly and indirectly). Apart from Mumbai, in the last one year, India has seen many terror attacks. Many people have been killed in the ghastly attached in Assam, Malegaon, Delhi, ahmedabad and Hyderabad.
Leaving the questions like:
- Who did this, who all are behind this?
- What were the intensions and what they were trying to gain?
let us look into, what the impact is.
The financial loss is accounted for Rs 4000 crore; this is mainly from the immediate business upsets. But what happens for the loss of life and disruptions to the daily life of common man.
Apart from the compensations from the Government will people benefit from anything else.
Are people insured??
Yes that is a big question and to ponder into the fine print (terms and conditions). "Unlike US and UK, we don't have any insurance cover against 'terrorist' acts. Loss of life due to terror may fall in the category," says an official of Kotak Life Insurance. [www.ndtv.com]

How to assess the risk from terrorism?
what are the potential consequences?
how frequent it can happen?
To answer above, it is becoming increasingly difficult by looking into the mode of operation, the extent of catastrophe and the uncertainity in the sequence of events (domino effects).

There are some countries who have some guidance on the insurance for terrosim related risk:

1. Australia
2. Austria
3. Finland
4. France
5. Germany
6. Israel
7. Namibia
8. Netherlands
9. Russia
10. South Africa
11. Spain
12. Switzerland
13. Turkey
14. United Kingdom

Source: wikipedia

More information is available from:
http://www.clydeco.com/services/expertise/insuranceandreinsurance/legal-guides.cfm?contentID=2135
http://www.iii.org/media/facts/statsbyissue/catastrophes/
http://www.riskandinsurance.com/0702choice.asp
http://www3.interscience.wiley.com/journal/118597786/abstract?CRETRY=1&SRETRY=0


SreeRaj R Nair
Risk Management

Disclaimer: The comments above are authors own view only and the author assumes no responsibility or liability incurred as a result of any use or reliance upon the information and material contained within or downloaded from its website. Hypertext links to third party websites are provided for the convenience of readers only. E&OE

Office - a risk to health and wellbeing?

A person working in an office is clearly at much less risk of injury than an employee on a construction site or an engineering workshop. But, there are numerous statistics showing that office work does pose a risk to health, safety and wellbeing.

What are the hazards? And health and safety problems related to office work?
- Occupational stress
- Musculoskeletal disorders (affecting back, upper limbs and neck)
- Slips and trips

DSE Risks:
Display screen equipment or more commonly computer workstations – the DSE users are increasing exponentially in recent years. DSE is not inherently dangerous to any health problems; the injuries, predominantly upper limb disorders (ULDs – aches and pain in hands, wrists, arms, shoulders and neck), results due to inappropriate working methods or poor organisation or insufficient breaks etc.
Some tips on using DSE / VDU (visual display unit)
- Get comfortable: adjust the screens, seats (height and posture), keyboard, mouse and documents to suit you; your forearms should be approximately horizontal and your eyes the same height as the top of VDU, free space for leg movement, avoid glare and reflections
- Keying in: a space in front of the keyboard is sometimes helpful for resting hand and wrists
- Mouse: use it with wrist straight, not stretched, loose grips
- Screen: adjust brightness, contrast to suit the lighting in the room, clean screen surface, suitable text size
- Posture and breaks: change posture, avoid repeated stretching to reach things you need, frequent short breaks
Source: www:hse.gov.uk/pubns/indg36.pdf

Assess the risk:
This should include risk from all the hazards identified in the office and related activities (workstation, stress, manual handling, electrical equipment, fire, ventilation, lighting, slips, trips, violence, noise etc).
Workstation: The ergonomic principle to follow is that the equipment should fit the worker, rather than forcing the worker to fit the equipment. In order to find what suits, a risk assessment need to be carried out.
There are numerous publications and checklist available for office safety and some specifically for DSE risk.
Eg. “the law on VDUs: An easy guide” (HSG90 ISBN 0-7176-2602-4)
www.hse.gov.uk/msd/index.htm
www.hse.gov.uk/electricity/information/maintenance.htm
www.hse.gov.uk/temperature/thermal
http://www.labtrain.noaa.gov/osha600/refer/menu15d.pdf
http://www.ccohs.ca/oshanswers/ergonomics/office/
http://www.comcare.gov.au/safety/virtual_office



Related regulations:
- UK, Management of Health and Safety at Work Regulations 1999
- UK, Health and Safety (Display Screen Equipment) Regulations 1992
- US OSHA – 29 CFR Part 1910 http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=FEDERAL_REGISTER&p_id=16305&bcsi_scan_42F16C56A779BF44=0&bcsi_scan_filename=owadisp.show_document
- Australia OHS Act 1991
- Australia OHS(CE)A(EIC) Act 2004 http://www.comcare.gov.au/ohs_legislation/ohs_acts__and__regulations

Greenhouse gas (GHG) emissions

A lot is talked about carbon trading, energy management, carbon foot print, reduce carbon emission etc and relates to greenhouse effect. What is it all about?

The greenhouse effect refers to the change in the thermal equilibrium of the earth (or a planet) by the presence of an atmosphere containing gas that absorbs and emits infrared radiation. The accumulation of greenhouse gases in atmosphere from the early days of industrialisation (more than 200 years) changed the upper atmosphere and now acts as greenhouse trapping more heat within the earth’s atmosphere and creating the effect of global warming.

Greenhouse gases (GHG) - some of the most significant are
- Water vapour
- Carbon dioxide (CO2)
- Nitrous oxide (N2O)
- Methane (CH4)
- Ozone
- Sulphur hexafluoride (SF6)
- Hydrofluorocarbons (HFCs)
- Perfluorocarbons (PFCs)

International bodies has identified the threat to the earth and urged to manage the situation. Guidance and initiatives in this regard are:
- World business council for sustainable development / World resource institute (WBCSD/WRI) published GHG protocol in 1998
- International Organisation for Standardisation’s ISO 14064, Parts 1-3 in 2008
- ISO 14065 and ISO 14066 (to come soon).
- Kyoto Protocol

Industrial and regulatory bodies are also in the process of incorporation GHG initiatives (quantify emissions etc.) into the environmental management system (policy and procedures).

Greenhouse gases are essential to maintaining the temperature of the Earth (otherwise the average temperature drops to -18oC), but excess of greenhouse gas can result in global warming (increase in the average measured temperature) and climate change.
Hence it is quite important to maintain a fine balance for the future of the Earth.

Piracy - the real one

The actual piracy – hijackings on the sea. Most common threat to shipping..

International Maritime Bureau (IMB) has got some alarming figures
Region Incidents
Africa (including Somalia): 120
Nigeria : 42
Far East : 11
Indian subcontinent : 30
South America : 21
South east Asia : 69
Rest of the world : 12

Courtesy: Adal RAfiq, ICIS reported, May 2008

2008 has seen an unprecedented rise in pirate attacks, according to the International Maritime Bureau. Between January and September, 199 piracy incidents were recorded, a third of them off the Somali coast. The latest of this was seizing the 330m long (1,100 ft) Saudi owned vessel - Sirius Star- which was carrying 2million barrels of oil.

From various sources

The issue is that, many of these vessels contains hazardous materials (chemicals, explosives etc.). The risk on the industry as such is on multiple grounds - no rawmaterial, production loss, projects on haults, economic loss.. and most serious the threat from the use of these materials for other destructive purposes!!

SreeRaj R Nair

Combustion (fire) and ignition

Fire is one of the major accident hazards and effects from flammable releases contribute to the risk from the process plant.

The three essential conditions for fire are fuel, oxygen and heat. The nature and presence of each of these decides the combustion process and the effects from it. Depending on the release phase (solid, liquid or gas), release velocity (flammable mixture available for combustion), and availability (and nature) of source of ignition the chemical reaction could result in different forms. The fire may be classified as jet flames, liquid fires (pool and running/drain), vapour cloud fires (with or without explosion), solid fires (solid materials, dust), warehouse fires and fires associated with oxygen.

Some potential ignition sources on process plants include naked flames, hot surfaces, hot particles, hot work, chemical energy, engines, vehicles, lightning, smoking, hot materials, hot gases, reactive materials, Pyrophoric materials, radio frequency emission, electrical equipment, static electricity, self-heating, arson and sabotage (more information can be found in Table 16.24, FPLees Loss Prevention and Process Safety, 3rd Edition).

Most of the issues related to explosion prevention and protection are addressed by ATEX Directive [http://ec.europa.eu/enterprise/atex/dir92-en.pdf]
In the UK, the requirements are as per DSEAR [http://www.hse.gov.uk/fireandexplosion/atex.htm]


Estimation of risk and probability of ignition:

Individual risk from an event resulting in fire (flammable effects) can be determined by
Individual risk = failure rate x ignition probability x fractional time of attendance x vulnerability
Where,
failure rate is the estimated frequency (per year) of the event that gives rise to the release scenario.
Ignition probability is the The probability that the release will ignite given that the failure has occurred (normally based on the release rate, see table below)
Fractional time of attendance is the maximum proportion of an individual’s time that is spent inside the building under consideration. This is fixed throughout representing one person for 40 hours a week.

A guide on selection of ignition probability for gaseous release is given in the following table.

IGNITION PROBABILITIES FOR GASEOUS RELEASES
Leak (kg/s) Probability of ignition
Gaseous release
Minor (<1) : 0.01
Major (1-50) : 0.07
Massive (>50) : 0.3

Liquid release
Minor (<1) 0.01
Major (1-50) 0.03
Massive (>50) 0.08

Courtesy: Cox, A.W., Lees, F.P. & Ang, M.L.; Classification of Hazardous Locations; IIGCHL, IChemE.; 1990

More information on ignition probability, is available in the IP research report., Ignition probability review, model development and look-up correlations, Published by Energy Institute, London, Jan 2006

Note: This is a small note on a factor that need to be considered while quantifying risk in process industry.

Reliable Toxic Detector cum Alarm

A Reliable, Available and Maintainable Toxic Detector n Alarm

Yes, this time I am mentioning about a most reliable option which could sense release (most of the releases with odour) and immediately sound an alarm!! To buy, instal and maintain, it costs very little only... it comes in two models - one with low decibal y alarm and the other with high decibal alarm. Wonder which company makes it!!
The detector is very common and often we come across in our daily..
okay.. not extending the elaboration..
It is nothing other than Chicken, oh yes, Cock (high decibel) and Hen (low decibel).

I'm serious, not joking.
I have seen a procedure describing how to use chicken (in a cage) as a detector to check the presence of hydrogen sulphide in a tunnel/man-way. Recently, also saw some pictures showing chicken (again in cage) paced in various plant locations as a detector and alarm for toxic gas releases. I've seen these being practised by leading names in the chemical process industry.
I am leaving you to guess which part of globe this could happen.

I would like to rewind to 2nd world war days.. where Russian army used the first line of defence as soldiers with ordinary guns against the heavy artillery from Hitler's side. Such a pity was the value of human during those days. Sitution have become better (or not?) for human beings, but not fellow fouls and animals.

Who knows, what all different types of exentric (or reliable!) source of detection and alarms people use in different parts of the world.

Asbestos - a hazard? How bad that could be...

On one fine day, on my way back from work there was a ‘warning news’ on the radio.. “Asbestos - the greatest single cause of work-related deaths in the UK; more people die from asbestos related diseases per year than are killed on the roads”.
I was quite shocked or bit hesitant to accept the acme of danger from asbestos. I thought of doing bit research into the facts and figures.

Some statistics as an eye opener:
In the UK,
- 4000 deaths a year cause by asbestos (as of today), the estimated peak at more than 5000 a year (by 2013).
- every week 20 tradesmen die from asbestos related disease
- every week 6 electricians die from asbestos related disease
- every week 3 plumbers die from asbestos related disease
Long delay between initial exposure and diagnosis; typically 15-16 years gap.

Asbestos can form a dust and enter the lungs. Because of its tiny diameter, asbestos fibre can penetrate very deeply into the lungs. You can’t see the small thin fibres, but being exposed to fibres over a period of time can cause lung diseases.

Asbestos related diseases:
Asbestosis: lung fibrosis (irreversible scarring of the lung)
Mesothelioma: cancer of the lining of the lungs or stomach
Asbestos-related lung cancer:
Diffuse pleural thickening: restriction of the lungs leading to breathlessness


Most of the buildings could contain asbestos in different forms. Some of the common applications using asbestos are for pipeline lagging, loose packing, roofing, fire insulation, asbestos insulation board, floor tiles, gaskets and asbestos cement.

Anyone who disturbs asbestos-containing materials, for example, by working on them or near them is likely to be exposed to asbestos fibres.


Wrong notions:
Only certain types of asbestos are dangerous
Nothing to take serious about it
Anyone can handle (especially remove) asbestos
You can treat and cure

UK HSE has a campaign called ‘The Hidden Killer’ to tackle risk from asbestos. More information in the following link: http://www.hse.gov.uk/asbestos/information.htm

End notes:
Avoid use of asbestos for any new build or refurbishments
Seek specialist advice and help in dealing with existing asbestos

Asbestos – a significant risk.

Consequence Assessment - DNV tool PHAST

Managing risk... First need to quantify the risk (semi or quanlitative are other options) For that, we should identify the hazard, estimate severity and then how frequent it could happen [Risk = Severity x Frequency]. For severty estimation, the extent of consequence from the event is to be predicted.

PHAST (Process Hazard Analysis Software Tool) by DNV is a software tool that I often use for consequence assessment. The coding of the tool started almost two decades back (sometime in late eighties). PHAST has developed ever since and still improving. I believe the wide recognition for the tool is mainly due to the technical support DNV offers and the continuous thrive to perform/satisfy the industry need. SafetiNL (Phast-Risk) is the only tool approved by the authority to perfrom QRA in the Netherlands. In the UK also, Phast is a widely accepted tool by Health and Safety Executive (HSE) and often used for the Safety Reports (COMAH / Seveso).

DNV Software organise Phast user group meeting. It provides platform to learn about the new developments in the forth coming versions, share the experiences from fellow users and ofcourse a good place to meet contemporaries. The number of such events held a year (across globle) reflects the growth and acceptance of the software tools for consequence assessment and the importance, industry is giving for managing risk.

The current version of Phast is v6.53.1. The next version V6.54 is expected to be available to the users by the last quarter of 2008. Following version v6.6 is due by mid-2009. After that, DNV is going for a major overhaul in the structure of the tool with its v7.x (and thereon). So far the improvements were mainly on improving the basic codes and adding on to that. It is expected that from v7.x, the architecture itself is recreated whereby more cross functional features (with Risk, Leak, Orbital - all are related DNV software tools) will be incorporated.

Some of the main features added on to the forthcoming version, i.e. Phast v6.54:
- Support MS vista
- Additional options for modelling impinged releases (don't get too excited, this feature enables the user to change the velocity reduction following impinged releases only. Earlier it was fixed to 25%. The changes in jet pattern, droplet formation, atomisation etc.. are far away from realisation).
- Short duration effects will be available for some more model options (time-varying long pipeline, leak, line rupture, disc rupture and relief valve scenarios).
- Greater control over trapped droplets for indoor releases (mass modification factor changeable).
- Warehouse modelling: Added a feature which automatically generate scenarios for Dutch PGS-15 Directive. This is available in table form and quite helpful for quick editing. Also, more complicated structural details could be considered (warehouse that is a part of a larger building, area and height changes etc). New materials can be created (rather than limited to the Phast provided warehouse material!).
- Advancements in the risk: risk ranking reports (more options like selection of top event or similar consequences etc.), define the outcome with a new code (e.g. INDXOF = Instantaneous release, No rainout, Delayed ignition, eXplosion Only, Free field ignition).
- New version will provide warning on license expiry.
- Provision for adding solar radiation to flame radiation.
- Greater control over graphs and maps. e.g. possible to plot effect zone in the graphs as well.
and many other minor corrections and updates.

Now looking forward to use and explore the advantages of the new features.

SreeRaj R Nair
Process Safety

An intro..

The concept of risk management, hmm....first we need to know what risk is! come on… who does not know what risk is… it is used so commonly by many of us daily.

To express in the technical terms one could define as the product of the severity from a potential incident or event and how frequent could it happen. Some examples could be:

- Risk from day to day activity (sprain, pain / ache, stress, impatience…)

- Risk from travel (including driving, being a passenger or just being a pedestrian)

- Risk from natural disasters (earthquake, flooding, avalanche, hurricane, epidemics…)

- Risk from industrial accidents (explosions, fires, toxic release, run-away reactions..)

- Risk from terrorist attack

- Risk from investments (shares market, debentures, capital expenditure, marriage…)

The list can go even longer, and yes that is the purpose of this place - to list down the different sort of risks around us and how could we tackle them. It could be anything from the risk in forwarding junk emails to risk in buying a bottle of drink from a local shop.