Cost Benefit Analysis Flashcards
What is the purpose of cost benefit analysis?
It estimates and totals up the equivalent monetary value of the benefits and costs of the community of projects to establish whether they are worthwhile.
What is the purpose of the disproportion factor (DF)?
If cost/benefit > DF then the measure can be considered to not be worth taking, on a cost basis alone i.e. it would be grossly proportionate.
What is the value of DF?
It is chosen, there is no generally established value.
What is the DF for low risk to members of public?
2
What is the DF for risk to workers?
up to 3
What is the DF for high risks and major hazards?
10
What is the definition of cost per life or preventing a statistical fatality (VPF)?
If a change will reduce rather than eliminating the risk the reduction benefit will need to be evaluated. This is expressed as cost per life saved.
When should improvements not be implemented?
The cost is grossly disproportionate to the target VPF.
What do we need to do to control hazards?
- identify
- assess
- eliminate
- control hazards and reduce risk
What is the relationship between complexity and (a) interactions (b) safety
(a) With a huge complexity, there are more interactions
(b) With a more simple system then this is safer.
What are the four ways in which we reduce risk?
- Minimising inventory: balance how much feed and product you have to store
- operating as close to ambient as possible
- substitute hazardous materials for safer ones
- dilute hazardous materials as far as possible
What is the key motto of inherent safety?
“What you don’t have can’t leak”
What are the three key words of inherent safety?
- substitution
- intensification
- attenuation
What is substitution in inherent safety? Give examples.
Use a less hazardous substance or process. e.g. water instead of flammable solvent and air instead of oxygen
What is the problem with substitution?
It may reduce “efficiency” but also reduces risk and consequential loss
