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Posted By Christian.H
Hi everyone I am looking for an example of a quantitative risk calculator. I have a couple of examples already although I am looking for more to compare, if there are any examples on the internet or if someone has one they can email me it would be great!
Regards, Christian
(It's for an OHS assignment)
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Posted By Merv Newman
go to "technical information" on this site and look for "risk management". A lot of good information there.
Merv
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Posted By Christian.H
Thanks Merv, I just had a look and there is some useful information there however I was still unable to find a quantitative risk calculator.
Does anyone else have any suggestions?
Regards Christian. Thanks in advance for any help.
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Posted By NeilM Poyznts-Powell
Christian,
Croner have a good risk calculator (6x6). If you can't get access please contact me and i'll send you it.
Regards,
Neil
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Posted By Christian.H
Thanks Niel, that was useful however that was a qualitative risk calculator not a quantitative calculator.
Quantitative calculators seem to not be very common.
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Posted By Andy Petrie
Having dealt with quantitative risk assessment for most of my proffesional career I can safely say that I have never used a 'calculator'.
The only thing I can think of is that for a very defined process with well understood failure modes and consequences that a hazard checklist can be used (such as the Dow fire and explosion process).
In reality quantified risk assessments need a degree of inteligence to go into them and using 'calculators' caould result in a bit of a botched job.
What are the examples that you alreaddy have? It may shed some light on what you are looking for
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Posted By John Allen
I’m not sure there is such a thing as a “quantitative risk calculator”. Quantitative risk is usually determined by the use of some form of decision tree. eg
What is the risk of (say) gas being released?
If it does release will it find an ignition source?
If it does ignite will the explosion result in fatalities?
If an explosion occurs will it escalate?
If it does escalate will people be killed trying to escape?
And so on. This can be done using a spread sheet although more sophisticated software is usually required for all but the simplest facilities. The starting point would be the probability of the initiating event occurring. For instance there is historical information on the frequency of gas releases. To this is added information from the plant concerned on area occupancy. From this point onwards assumptions must also be made. eg everyone in the immediate vicinity of the initial explosion will become a casualty or x per cent of people will be killed trying to escape. Generally these assumptions should err on the side of caution so that the QRA demonstrates the worst case and you can then use qualitative arguments to demonstrate that in reality the situation is safer eg a blast wall will protect people trying to escape, or area occupancy is based on highest not typical figures.
Some of the larger consultancies have bespoke software which makes these calculations. This might be the “Calculator” you are looking for however the normal arrangement is that the client pays to have the risk for his plant “crunched” through this software as part of his Safety Case/Report submission.
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Posted By Christian.H Thanks everyone below is my assignment well part of it.
Define what is a quantitative and a qualitative risk calculator. Outline the advantages and disadvantages of quantitative versus qualitative measurements. Find examples of four different risk calculators. You must provide an example of at least one quantitative and one qualitative calculator. You can use sources from books, journals, the Internet and so on. You may even find an electronic version of a risk calculator. Make sure you reference your sources. Briefly discuss each risk calculator and provide the following information: * the type of calculator (qualitative, quantitative or a mixture of both); * the type of risk categories it would be suitable to measure; * the weaknesses; and * the strengths.
I have many examples of qualitative calculators (analysis) from work, internet, friends etc. I was even emailed one today from Neil...Cheers. However quantitative calculations (analysis) is not so easy to find. The AS/NZ 4360:2004 and HB 436:2004 (I am from Aus. Studying a Degree in OHS) helped shed some light as did the website: http://www.systemsafety....~journal/clifsnotes.html "Quantitative analysis involves the use of numerical or quantitative data in the analysis, and provides a quantitative result. In a quantitative analysis, mathematical theories and models are used to calculate mishap risk factors. It is important to recognize that models are the analyst’s view of a system and not the actual system itself. Don’t ever confuse mathematical model results with reality. "
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Posted By Christian.H
Therefore the quantitative calculator may not seem so much like a calculator however it helps generate a result/answer and numbers are used to do this?.......... Thats my understanding anyway?
I could obviously contact my lecturers however I thought it would be best to try and work it all out myself....well with help from others (such as people reading this and replying) I will speak to my lecturers if it's essential!!
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Posted By Christian.H
John I think yours makes sence and thats what I am after, however as I have never seen/dealt with a proper one filled out it makes it harder to picture.
(Sorry when I said I already had an example that was simply what is included in the standards, which isn't anything special and obviously didn't quite get the message across although I'm still working through it. I am also trying to round one up from my work experience employer)
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Posted By Christian.H
I have an example of a semi quantitative calculator if anyone would like to see it just email me. ....
Quantitative methods of risk analysis include—
• consequence analysis;
• statistical analysis of historical data;
• fault tree and event tree analysis;
• influence diagrams;
• life cycle cost analysis;
• network analysis;
• simulation and computer modelling;
• statistical and numerical analysis;
• test marketing and market research; and
• probability analysis.
"Quantitative analysis uses numerical values (rather than the descriptive scales used in qualitative and semi-quantitative analysis) for both consequences and likelihood using data from a variety of sources.
The quality of the analysis depends on the accuracy and completeness of the numerical values and the validity of the models used.
Consequences may be determined by modelling the outcomes of an event or set of events, or by extrapolation from experimental studies or past data.
Consequences may be expressed in terms of monetary, technical or human impact criteria.
In some cases, more than one numerical value is required to specify consequences for different times, places, groups or
situations."
My Apologies for the multiple and long posts
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Posted By John Allen Christian, you might like to try this site - http://www.hse.gov.uk/offshore/information.htm look under "Guidance on ALARP for offshore inspectors" paras 26-27 give an outline of how and where quantitative risk assessment is used.
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Posted By Christian.H Thanks John that helped get my head around it a little. Do safety professionals use quantitative risk analysis often? I also stumpled across: www.enre.umd.edu/ctrs/report.pdf there seems include an example of a quantitative risk analysis (calculation), what do you think? Regards, Christian
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Posted By Andy Petrie I use quantified analysis all the time, usually it just takes the form of a simple calculation, e.g. likleliehood of incident, no of people esposed, likelihood of harm, effect of mitigation measures etc. Some software packages are Fault Tree + from isograph, this is a good fault and event tree package which allows you to calculate risk levels very effectively (assuming the info you put in it is reliable). http://www.isograph.com/The RSSB (railway safety and standards boards) has a very detaile model for railway risks, it's on their website. In industry I have used a package called SHEPPERD (i think that's how you spell it) from Shell, which is used to model fires, explosions, toxic releases from Chemical/Oil&Gas sites, http://www.shellglobalso...oftware/shepherddesk.htm
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Posted By Andy Petrie
p.s. my spelling is not usually that bad ;0)
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Posted By Merv Newman
Sorry, I misread your request and pointed you into the "qualitative" area which most of us are more used to.
I believe that quantitative risk calculations are made all the time, but rarely for "people safety".
Industries such as aeronautics calculate levels of risk based on experimental and test data to specify, for example, intervals between maintenance or replacement or critical parts. This will give them a number known as the MTBF or "mean time between failures" which will indicate the optimum time to intervene before the wheels come off. Or the gas valve will start to leak because the washer has perished.
I know that the above IS directly related to "people safety" but such calculations are usually made by engineers or chemcial engineers. Not by yer avrge CMIOSH
Suggest you look for an answer in high tech engineering or the chemical manufacturing industry.
Please dont ask me - I have no idea of what I am talking about.
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Posted By Merv Newman Try this link for a fairly good explanation with examples (not worked). I got to this by googling "quantitative risk evaluation" ps. we are not talking "assessments" which can lead to vague approximations ; highly unlikely, quite likely, unlikely, but of numbers derived from quantitative tests or quantitative observations http://www.rcfc.net/risk.htm
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Posted By Christian.H
Thanks all for your help, links are good and I now have a better understanding on quantitative risk analysis, hopefully I shall now be able to get through my assignment fine, well hopefully a little better then just 'fine'.
Regards, Christian H
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