Some statements on safety

Following are some of the statements in "Process Safety Analysis - An Introduction"  by Bob Skelton published by Institution of Chemical Engineers, UK.

1. A good safety culture ensures that both the spirit and the letter of the law are fulfilled.
2. Attitude to safety should be highly visible and shared at all levels within the company.
3. A well managed company is almost invariably not only a profitable company but a safe company.
4. Changes in existing plant are costlier than that introduced in design stage.
5. Design should be such that operator intervention is not needed for at least 30 minutes after an incident. Experience has shown that operators can not always be relied upon to make the correct decisions under immediate post-accident conditions.
6. Safety in design must be both proactive and reactive. Changes, once a plant is built, are very expensive compared with changes at the design stage.  It is not sufficient and cost efficient to make safety review after completing the design and then BOLT ON safety devices. It will not be cost effective. Engineered safety is BOLT ON safety. Engineered protective devices can fail and never place too much reliance on BOLT ON safety.
7. Commissioning is one of the most hazardous parts of any process plant operation. Not only do design errors which escaped previous checks manifest themselves but problems due to construction errors also become obvious. In addition commissioning generates hazards of its own as the plant moves from construction to operating status. It is essential that a formal set of checks be carried out before process fluids are introduced for the the first time.
8. Fire and explosions can be prevented  by not exceeding 25% of LEL. Flammable atmospheres can be avoided by ensuring that fuel lines and tanks are pressurized so the flammable material leaks out rather than air leaking in. good ventilation of vessels and plant areas can maintain safe working conditions.
9. Dust explosions are best prevented by good housekeeping - that is, by keeping the concentrations of dust down and perhaps keeping the dust damp. Inerting by dilution with non-combustible dust is another effective technique, frequently used in coal mines.
10. The risk is serious in case of static electricity, if the relative humidity is below about 60%.
11. Explosives manufacturing facilities are usually designed so that the buildings are separated by safe distance, surrounded by earth mounds so that any explosion will go upwards rather than affect other plants in the area. In addition there is usually a limit on the number of people allowed in a building.
12. Fire fighting water causes more damage than the fire itself, when polluted water is let into rivers. There may be a conflict between accepting the atmospheric pollution caused by letting the fire burn out and the water-borne pollution caused by fighting it.
13. Non-process hazards account more than 70% of all accidents in process plant.
14. Many of the worst accidents in the process industries are the result of bad maintenance practice. Ex: Piper Alpha and Flixborough
15. As many people die by asphyxiation as from toxic gases.
16. A good health and safety policy is always cost effective; most organisations grossly under estimate the cost of accidents, often by an order of magnitude. The organisation should be such that the attitude to safety is highly visible and shared at all levels within the company. Active participation is encouraged to promote the objectives of not just preventing accidents and industrial illness but motivating and empowering everyone to work safely.
17. A safety culture, once established, must be maintained, any any tendency to careless practices stamped out at once. Experience shows that 80% of accidents tend to happen to 20% of the workforce - the young and the old being particularly vulnerable.  Many accidents are caused by operators not fully appreciating the significance of small, but nevertheless important changes.
18. A good system of accident reporting is proactive and reactive, whereas most tend to be purely reactive.
19. Effective safety at all stages of a project - from inception to demolition - can only be achieved if there is a commitment at all levels. The senior management must see health and safety as being just as important as profitability and they must make certain that all their workers are aware of this fact.
20. A well managed company is almost invariably not only a profitable company but a safe company.
21. In hazard analysis, a distinction must be made between routine operator action and operator intervention in an emergency.  For routine operator action, the operator can usually take time and is under no great stress. Safety assessments involve the prediction of the likelihood of errors when the operator is taking corrective action against alarms. The time for corrective action may short, the operator is liable to be under some stress and so the probability of errors is greater.
22. Total elimination of human error will never be possible. Use must be made of the science of ergonomics to ensure that everything possible is done to enhance the strengths of human operators whilst at the same time allowing for the weaknesses.
23. The most important rule is, 'inherent safety is better than engineered safety', ' what you have not got can not leak'. Even elaborate safety devices can't reduce risk to zero due to the escape of a noxious substance, but replacing a noxious substance by a more benign one could well eliminate that risk altogether.

 

Green Chemistry

There is an article in Chemical & Engineering News on 27.06.2011 about green chemistry, the history behind its development, 12 principles of green chemistry, sustainability and its role in accident prevention and environment protection and its use in business.

Home poisons - tips to handle the dangers

There is an article in The Phillippine Star about 10 most common poisons at home that are likely to harm children health and one of the poison in the list is paracetamol, though I do not know how it can cause harm. An article in internet is given here about paracetamol use and hazards. The other items in the list include kerosene, caustic, paint thinner, pesticides and button cell batteries. Tips given for preventing poisoning include reading product labels about hazards, usage and disposal, personal hygiene, proper storage, etc.

Slipping on ice

Last week I was on a personal tour and walked a bit on snow mountains. I saw water flowing down under ice and some of the tourists are sliding from heights on a sledge nearby. There were no barricades to prevent accidental fall into flowing water from ice melting, ending up under ice in-between and resurfacing at distance away. If any anybody looses control during sliding/skating, he/she may not be alive as it is likely that the passage under the ice is not big enough to allow onto the other end and one can not climb back as the water is flowing at great force. This is first time I went to snow mountains and is a lesson for me.

Heavy winds upturn 7 containers and flyoff 2 drivers

There were reports of heavy winds in Srikakulam district, Andhra Pradesh, India on 10.06.2011. Seven containers on the road were upturned, two drivers on the road flew 20 feet high and fell down receiving injuries and broken bones/joints, many electric poles, houses and trees were uprooted. The wind speed was about 500 kmph. Incidents like this are rare in India.
Now imagine if somebody is working on the building roof (work at height jobs) or trestles. Normally in coastal areas, wind speeds are very high and may reach even 200 kmph. This, if coupled with low pressure and accompanying heavy winds can lead to above incidents. In maintenance jobs of roofs, safety advisor will not allow work on roof during winds and rain because of the apprehension that asbestos/metallic sheet roofs can fly off, persons at the top will not have strong foothold, asbestos sheets can become soft due to rain and lead to fall of persons. But maintenance department views such advise as hindrance to work and pass sarcastic comments. The video link is to be seen by such people so that they can be careful in future.

Dust explosion

There is one more dust explosion at Hoeganaes facility, Tennessee on May 27th in which two persons died and another is seriously injured. Earlier in the explosion on 31st January, two persons died and a person was injured during the flash fire on 29th March. My post on 14th May gives some details of iron dust explosion provided at CSB website. The latest incident appears to be initiated by hydrogen gas leak from 3x7 inch hole on a hydrogen pipe in a trench. The trench also contains nitrogen and water lines. After hearing hissing sound from the trench, nearby annealing furnace operators informed maintenance who unsuccessfully tried to remove the trench cover. Later tried to open with the metal chain hooked to a forklift and during cover opening, a flash and explosion occurred. The statement for news conference on June 3, 2011 by CSB gives status of their investigations and a short video (1:16 min) on iron dust flash fire experiment.
The shortfalls at the plant identified are poor containment of dust, improper dust collection, thick layers of dust, unsuitable electrical fittings and availability of various ignition sources nearby.These types of causes are well reported and NFPA Standard 484 and we fail to take measures to eliminate these types of causes.
Providing dust containment and collection, elimination of ignition sources, flameproof electrical fittings, providing and maintaining obstruction-free aisles, regular wet mopping and incineration of mops at safe distance, testing of electrical continuity between equipment and earth pits, maintaining 50-60% humidity, use of antistatic uniform and PPE are some of the measures that will surely help in avoiding such incidents.

17 year old dies during height increase exercise

A 17 year old boy dies due to entanglement of nylon cloth sari. He used to practice height improvement exercise by hanging from ceiling and at the time of the incident nobody was present in the house. As the local inspector found this during his initial investigation means that others in the house know about this. The boy should have been counselled to desist from such so called exercises. It is unfortunate to have such accidents and we can't call this type of accident as freak. Children, if not corrected at young age, will develop wrong attitudes and their whole life will be at risk.

Protect children from pollution - a cartoon in Deccan Chronicle

A cartoon on pollution in the cities and protecting school going children from pollution.
Counterpoint Deccan Chronicle

LINK

Electrocution of two contract workers

As per news paper report, two persons died while climbing down the electric pole after doing repair jobs on a 11 kv feeder line. As per the reports, after the incident, other contract employees disconnected the power supply. It is a basic rule to deenergize the lines before taking up any maintenance jobs on or near electrical lines, electrical fittings and restore power supply only after ensuring that the planned work is completed and persons landed down safely.
As I mentioned in my earlier posts, one should not opt for shortcuts. There is no urgency in restoring the power supply, when lives of workers on the line are at risk. If the rules are not followed, then incidents like this continue to occur. Rules are repository of experiences so many persons who lost their lives and we need not learn afresh by endangering our own lives. Proper supervision is also required, particularly when we engage contract workers as they live on daily wages and do not have facilities like those regular employees. We should not cut cost at the cost of valuable lives.

Fall and death of a boy in corn machine

As mentioned in a local news paper report, a boy died due to fall in the corn processing machine while adding corn to the machine. The 14 year old boy went to fields with his buffaloes and he was engaged in the machine feeding job. The boy's head and part of the body got crushed in the machine. As per the picture, it appears that there is no proper access and platform for doing the job, and no guard rail/barricade to prevent fall of persons. I am not clear whether Factories Act and Rules can be applied or not, but the spirit of the rules can be followed in all walks of life. As per the rules, children should not be engaged for work on or near moving machinery. Even local government rules prohibit engaging child labour. The news paper report in local language can be read here.