Posted By Dr Chris French
In a recent discussion with regard to risk assessment, we got on to the topic of whether risks are acceptable or tolerable. Is there any right or wrong answer? Do some people accept risks but others not only tolerating them?

I would be grateful if anyone could shed any 'official' light

Chris French

Posted By Geof
Of course there is also some credibility in the idea of keeping it simple so that the ones at the sharp end can buy into it!

Posted By Raymond Rapp
Chris

Whether 'residual risk is tolerable or acceptable' is I suggest largely a matter of semantics. Succinctly illustrated by one particular wag.

The HSE have produced various documents on the TOR (Tolerability of Risk) criteria which identifies 4 or 5 different processes for quantifying the TOR concept. However, most of these processes are subjective with the exception of a QRA, CBA etc. Even CBA require a certain amount of subjectivity in terms of the morality of risk.

The best explanation of risk, residual or otherwise, is on a 'risk and reward' basis. In other words, there is only an acceptable risk if the potential reward justifies the risk, at least for that particular person or group. Hence people will see risks differently because 'reality' is socially contructed and therefore difficult to measure objectively.

Regards

Ray

Posted By Geof
Defined by whom?

Posted By Alec Wood
The use of "tolerable" rather than "acceptable" emphasises that residual risks should be further reduced if practicable.

One may do everything reasonably practicable to reduce risk in a given situation and end up with what is still a medium to high risk activity. Such risk should not be accepted for ever more, but may be tolerated in the short term.

For example, years ago the inspection of radioactive highly contaminated areas was carried out by people wearing protective equipment, some still is. This risk was tolerated until the technology was developed allowing the much more common robotic inspection systems we see in use today. If the risks these technicians faced had been "acceptable" then there would have been no need to develop alternative technological systems and solutions.

When audited for OHSAS18001 by BSI we were asked to ammend our general production activites risk assessment forms to "indicate what level of risk is tolerable (NOT acceptable) under normal circumstances in your everyday factory operations". The auditor's explanation for this text was as given above.

Alec Wood
Samsung Electronics

Posted By John Allen
Official light! Checking the HSE guidance again it appears that they see “tolerable” as a band between “unacceptable” and “acceptable”.

Guidance on ALARP for Offshore Division Inspectors
Making an ALARP demonstration
http://www.hse.gov.uk/offshore/circulars/enf38.htm
“Risk criteria and tolerability - The HSE framework for the tolerability of risk shows three regions:
1. A region of high risk – unacceptable region.
2. A region of intermediate risk – tolerable region.
3. A region of low risk – broadly acceptable region.
Unacceptable Region - a risk falling in this region is regarded as unacceptable whatever the level of benefit associated with the activity.

Tolerable Region - a risk falling in this region is typical of the risks from activities which people are prepared to tolerate to secure benefits. There is however an expectation that such risks are properly assessed, appropriate control measures are in place, residual risks are as low as is reasonably practicable (ALARP) and that risks are periodically reviewed to see if further controls are appropriate.

Broadly Acceptable Region - a risk falling in this region is generally regarded as insignificant and adequately controlled. None the less the law still requires further risk reductions if it is reasonably practicable. However, at these levels the opportunity for further risk reduction is much more limited.”
I appreciate that these concepts may be too difficult for some people who inhabit these threads. However when I talk to the workforce involved and exposed to such risks they are fully informed, understand the concepts and are able to discuss the risks rationally. They will know for instance how these risks compare with other occupations and other human activities, eg driving or sport. They know too that quantitative assessments are at best estimates and are only as good as the consistency and validity of the assumptions made in their calculation. As a result they will be more interested in the strength of the qualitative assessments made.
Finally, they will know that in calculating whether an ALARP solution has been achieved a value may have had to have been put on human life. They will not emotionally react to this knowing that this is done in many walks of life and that the value chosen is well in excess of that they have chosen for themselves or is used by the state. No obscure scores used at all.