CE20223 - Safety and Ethics Flashcards
What’s a hazard?
A property or condition which can cause an unwanted event.
The can result in near misses and incidents
What does the fire triangle consist of?
Fuel + oxygen + energy
Need all three to be present to get a fire
Oxygen my be bound in the fuel e.g. ammonium nitrate
What are flammable limits?
The fuel concentration, in % by volume of air, must fall within certain limits (LFL - UFL) before it will combust
Typically between 1-10% for most hydrocarbons.
H2, H2S and C2H4 have wide flammable ranges.
What’s the flash point?
Lowest temperature at which a liquid gives off enough vapour to form a flammable mixture with air.
• Some hydrocarbon liquids released to the atmosphere are not hot enough to give off enough vapours that can be ignited by an ignition source
• For safe product handling/storage,
typically use ‘Closed Cup Flash Point’
to characterise the flammability
What’s the auto-ignition temperature?
Temperature at which vapours will spontaneously ignite.
- Some process streams are hot enough that when they escape to the atmosphere they will catch fire immediately and so do not need an ignition source
- In practice temperature at which autoignition occurs is > theoretical AIT
What do the parts of the fire diamond suggest?
Blue - health/toxicity
Red - flammability
Yellow - reactivity/instability
White - special notice
0 is lowest, 4 is highest
What are examples of potential ignition sources?
Fired equipment / Hot surfaces - controlled by equipment spacing
Maintenance hot work - controlled by Work Permit System
Electrical equipment - controlled by Work Permit System and electrical area classification
Vehicles - controlled by Work Permit System and plant layout/spacing
Electrostatic ignition - controlled by earthing, design and procedures
Lightning - controlled by earthing structures
What are examples of potential fuel-air mixtures within equipment?
- Fired heaters
- Decoking and catalyst regeneration
- Air used for reaction - oxidation, sweetening, etc.
- Air blowing lines
- Vacuum systems
- Fixed roof tanks
- Tank trucks/railcars/barges/ships
- Sewers
- Confined/recessed areas
- Flare system
- Startup and shutdown
What are examples of equipment failures for potential loss of containment?
- Corrosion
- Improper material of construction
- Brittle fracture
- Gasket leak
- Small bore piping failure (vibration/mechanical damage)
- Seal leak from pump/compressor
- Furnace tube failure
- Overheating / exotherms
- Over/under pressure
- Freeze-up / thermal expansion
- Pipe-line surge (‘water hammer’)
- Check valve / safety valve failure
- Hose / loading arm failure
- Bellows failure (Flixborough VCE 1974, full lecture)
- Rupture from collision
What are examples of operating procedures causing potential loss of containment?
• Taking equipment out of service:
- Equipment draining /
depressurizing / blinding
• Bringing equipment back into service:
- Deblinding
• Tank / tanker filling
• Tank gassing / frothovers
- Routing light product to tank
- Routing water to hot tank / hot
product to cold tank
- Purging / venting
- Draining water
- Sampling
What are VCEs?
Vapour cloud explosions
Gas or vapours escaping to the atmosphere can form a flammable mixture, which if ignited, can produce an explosion (VCE) followed by a fire.
Ignition of a flammable cloud in an open area will normally produce a flash back fire with low levels of overpressure.
When do VCEs occur?
Vapour cloud explosions require the flammable cloud to be within a congested area.
Multiple obstacles increase turbulence of the flame front. This increases both
the flame speed and the magnitude of the pressure wave. The increase in pressure causes an increase in temperature / Ek. This can act as an ignition source.
VCEs are more likely to occur with a large amount of fluid, involving
release of LPG or volatile liquids.
VCEs can produce a damaging overpressure wave which can cause
non-blast resistant buildings to collapse, and also result in secondary
equipment failures and fires.
What is the difference between deflagration and detonation?
Deflagration is more typical of explosions resulting from flammable releases to atmosphere (flash back fires, unconfined vapour clouds).
- Flame front travelling at subsonic velocity.
- Overpressure normally <1 barg.
Detonation is likely to occur inside a confined space (e.g. tank, pipe)
- Flame front travelling at supersonic velocity produces a shock
wave which compresses and pre-heats reactants ahead of flame
front.
- Overpressure typically > 10 barg.
What’s deflagration?
Combustion which propagates through a gas or across the surface of an explosive at subsonic speeds, driven by the transfer of heat.
A fire is a slow form of deflagration.
Deflagration is more typical of explosions resulting from flammable releases to atmosphere (flash back fires, unconfined vapour clouds).
The flame front travels at subsonic velocity.
Overpressure normally < 1 barg.
What’s detonation?
Combustion of a substance which is initiated suddenly and propagates extremely rapidly, giving rise to a shock wave.
Detonation is likely to occur inside a confined space (e.g. tank, pipe).
The flame front travelling at supersonic velocity produces a shock
wave which compresses and pre-heats reactants ahead of flame
front.
Overpressure typically > 10 barg.
What are the impacts of VCEs on people for different peak over-pressures?
1 psi - knock personnel down
5 psi - ruptured eardrums
10-35 psi - damage to lungs up to threshold fatalities
50-65 psi - 50-99% fatalities
How is a process analyses?
Describe process under normal conditions
Describe the event itself
What was learnt from the accident / how can it be prevented
Analysis of the Flixborough VCE 1974 accident:
• Cyclohexane was oxidised to cyclohexanone (a precursor for
the manufacture of Nylon) by injecting air in the presence of
a catalyst.
• The process of oxidation is relatively slow and six stirred reactors were used in series.
• Reaction kinetics dictated that the cyclohexane in the reactors should be maintained at 155°C and 9 barg – liquid
phase.
• When released to atmosphere some of the liquid flashed-off creating a vapour cloud.
Adiabatic flash of reactor inventory (100 t) gives ~40 t vapour
cloud.
- 28 employees were killed (mostly inside buildings) and 36 injured.
- Extensive damage to process plant.
- 53 members of public injured and 1800 houses damaged.
• Release occurred due to failure of temporary piping/flexible bellows.
- A relatively simply bypass had been installed to allow one of the reactors to be taken out of service for repairs.
• The temporary bypass had not been properly engineered or reviewed.
- No engineering drawing prepared and only basic calculations were carried out.
- Lack of necessary engineering expertise.
- Maintenance team did not recognise that offset piping
created bending moment and high shear forces at
bellows.
• No structured process for reviewing and authorising changes.
• Occupied buildings were not blast resistant and were located
too close to process areas handling highly flammable material.
This could be prevented by double checking calculations
How do ethics and morality differ?
Morality is the difference between right and wrong
“The totality of opinions, decisions, and actions with which people express, individually or collectively, what
they think is good or right”.
Ethics is the systematic reflection on morality.
- how to make moral judgements. There are many ethical theories and frameworks designed to help people arrive at good moral judgement.
- can be ‘DESCRIPTIVE’ concerned with existing morality, or ‘NORMATIVE’ when it tries to produce recommendations about how to act or live.
What are the 6 moral competencies?
Sensibility Analysis skills Creativity Judgement Decision-making Argumentation
What are the 3 Ps for corporate social responsibility?
People
Planet
Profit
What are the key aspects of honesty and integrity?
Act in a reliable and trustworthy manner
Respect confidentiality
Declare conflicts of interest
Reject bribery and improper influence
What are the key aspects for respect for life, law, the environment and public good?
Hold paramount the health and safety of others and draw attention to hazards
Recognize the importance of cyber security and data protection
Protect and improve built and natural environments
Maximise the public good and minimise both actual and potential adverse effects for their own and succeeding generations
Take due account of the limited availability of natural resources
What are the key ethical aspects considering accuracy and rigour?
Perform services only in areas in which they are currently competent or under competent supervision
Keep their knowledge and skills up to date
Assist the development of engineering knowledge and skills in others
Identify, evaluate, quantify, mitigate and manage risks
Not knowingly mislead or allow others to be misled
What are the key ethical aspects when considering leadership and communication?
Promote equality, diversity and inclusion
Promote public awareness and understanding of the impact and benefits of engineering achievements
Be objective and truthful in any statement made in their professional capacity
Challenge statements or policies that cause them professional concern
What are the 4 main ethical principles?
Honesty and integrity
Respect for life, law, the environment and public good
Accuracy and rigour
Leadership and communication
What are the 3 ethical theories?
Consequentialism
Deontology (duty ethics)
Virtue ethics
What are values, norms and virtues?
Values - lasting matters that people feel should be strived for in general to realise a just society
Norms - rules that prescribe what actions are required, permitted or forbidden
Virtues - certain type of human characteristic or quality
What’s consequentialism?
Consequences of actions are central to the moral judgement of those actions.
Utilitarianism actions are judged by the amount of pleasure and pain they bring about - by their ability to benefit a majority.
Considers profits and losses / pleasure and pain.
What does deontology / duty ethics consider?
Duty is a better guide to decision making than pleasure.
Action is considered morally right if it agrees with a certain moral rule.
This rule says ‘you may not lie’ and there are no circumstances under which it is morally right to lie.
What does virtue ethics consider?
An ethical theory that focuses on the nature of the acting person. This theory indicates which good of desirably characteristics people should have or develop to be moral.’
Variant: Aristotle’s (322 – 322 BC) Theory
Each moral virtue (character virtue) holds a position of equilibrium and it is the middle course between two extremes of evil
E.g. A courageous person will not act as a coward in a dangerous situation, but he/she will also not be reckless and ignore the danger.
What’s universalism?
A system of norms and values that are universally applicable to everyone, independent of time, place or culture.
What’s the categorical imperative, universality principle and reciprocity principle?
Categorical imperative A universal principle of the form “Do A” which is the foundation of all moral judgments in Kant’s view.
When judging the morality of an action, it should not lead to a contradiction (self-defeating)
Universality principle: First formulation of the categorical imperative: Act only on that maxim which you can at the same time will that it should become a universal law.
(1) Assume the action is morally correct when you act on it – (2) Assume that everyone can also follow this norm (universality principle) – (3) will this norm survive?
Reciprocity principle Second formulation of the categorical imperative: Act as to treat humanity, whether in your own person or in that of any other, in every case as an end, never as means only.
What’s the Kantian theory?
What are it’s criticisms?
We can speak of good will if our actions are led by the categorical (= unconditional) norm ( = rule).
E.g. If rule says ‘ you may not lie’ there are no circumstances under which it is morally right to lie.
Vs. Hypothetical norm A condition norm, that is, a norm which only applies under certain circumstances
Criticism:
According to Kant all moral laws can be derived from the categorical imperative. Bending rules is not allowed.
Do all these laws form an unambiguous and consistent system of norms? What about contradictory norms (e.g. whistle-blowing)
Kantian theory (and duty ethics) often elicits the objection that a rigid adherence to moral rules can make people blind to the potentially very negative consequences of their actions
Ford Pinto Ethics Case Arguments:
Ford made a cost-benefit analysis to justify actions which showed that total social costs of retrofitting all the cars > social costs of the expected accidents.
Objections against utilitarianism:
(1) amounts of money attached to different kinds of pain (dead, injuries) seem rather arbitrary (some were based on government documents)
(2) Reliability of the estimates (e.g. the number of fatalities)
By deciding solely based on considerations of overall welfare or happiness, Ford adopted a policy of allowing a certain number of preventable deaths/injuries. The case reveals abuse because the victims were sacrificed to optimize overall welfare (the ends justify the means).
Abandoned the “you cannot put a value on human life” or the freedom principle of Mill.
Universality principle: “Ford will market the Ford Pinto, knowing that the car is unsafe and without informing the consumers”
Can this become a universal law and be without contradiction?
“Marketing unsafe cars without informing the consumers is allowable.”
- Loss of customer trust and hence marketing a car would become impossible.
Reciprocity principle: Implies respect for people’s moral autonomy in making their own choices - Ford should have informed its consumers about the safety of the Pinto - so they can make an autonomous rational decision on the car purchase.
Failing to inform them, the rational agency of the consumer was thus undermined, and they were used as merely a means to achieve Ford’s aim: increasing Ford’s turnover
What’s an ethical cycle and what are the 5 phases?
A tool in structuring and improving moral decisions by making a systematic and thorough analysis of the moral problem, which helps to come to a moral judgement and to justify the final decision in moral terms.
1) Moral problem statement
2) Problem analysis
3) Options for actions
4) Ethical evaluation
5) Reflection
Leading to morally acceptable actions
What is mentioned when formulating a moral problem statement for problem analysis?
- State what the problem is
- State relevant facts
- State relevant moral values
Consider shareholders and their interests, who has to act and the moral nature of the problem.
What are the three different strategies for phase 3 - options for actions within an ethical cycle?
Black-and-white strategy
Cooperation strategy
Whistle-blowing strategy
What’s the black-and-white strategy (in ethical cycle)?
A strategy for action in which only two options for actions are considered: doing the action or not.
(Not useful for more complex situations)
What’s the cooperation strategy (in ethical cycles)?
The action strategy that is directed at finding alternatives to help solve a moral problem by consulting other stakeholders (can lead to win-win situations)
What’s the whilst blowing strategy (in ethical cycles)?
Going public with the information; used as a last resort strategy as it is quite damaging to both the individual employee and the organization.
What is considered in the ethical evaluation of an ethical cycle?
You must evaluate the moral acceptability of the various options for action.
These judgments need not be the same because different frameworks can result in different preferred options for action in each situation.
Based on both formal (based on professional ethics such as codes of conduct and the main ethical theories) and informal moral frameworks (intuitions and common sense)
Intuitivist framework: indicate which option for action in your view is intuitively most acceptable and formulate arguments for this statement.
Common sense method: weigh the available options for actions in the light of the relevant values.
Eg: although making a profit is important, the value that is really at stake is public safety
What do HAZOP and HAZID stand for?
Hazard and operability (HAZOP)
Hazard identification (HAZID)
What’s risk?
Risk is a measure of the hazard release potential.
It’s the likelihood of something negative happening
- Prerequisite: you know/understand the hazard!
- Minimise hazard (and risk) through inherently safer design
- Minimise release potential through designed and procedural control measures
How can hazards be measured?
1) Dow Fire & Explosion Index (F&EI)
- Semi-quantitative approach (numerical result).
- Output provides an overview of risk exposure and not a
specific list of potential deficiencies/hazards.
- Can provide estimate of Maximum Probable Property
Damage.
- Useful in ranking different alternatives.
2) Monod Index
- Developed by ICI (Imperial Chemical Industries) after Flixborough.
- Based on Dow Index, modified to address wider scope of hazards.
- Includes plant layout and separation between hazardous units.
What do values for the Down F and EI suggest about a hazard?
1-60: light
61-96: moderate
97-127: intermediate
128-158: heavy
159 < : severe
What is material factor, MF?
A measure of intrinsic rate of energy release due to fire or explosion.
How is the F and EI Dow index calculated?
F&EI = MF * F1 * F2
Where MF is the material factor, F1 are the general process hazards and F2 are the special hazards.
How is material factor, MF, obtained?
From NFPA (national fire protection association) ratings. Based on most dominant/highest risk material present.
It’s the product of Nf (flammability) * Nr (reactivity)
(Non-combustible/stable - MF equals 1
Highly reactive/flammable - MF equal 40)
How are F1 and F2, considering general and special hazards, calculated to find F&EI index?
F1/2 = total number of penalties + 1
1 is the base factor
