Author Archive: abhisam1
Explosion in China while unloading chemicals
Last week a deadly explosion occured while workers were unloading a lacquer-curing agent from a truck at Jinlan Logistics Town in Lanshan District, Linyi.
Seven people died immediately and 11 others died of injuries in hospital. Of those 14 were women. In all it required 26 fire engines and 91 firefightersto put out the blaze. It is now learnt that the lacquer contained xylene and butyl acetate, each both inflammable and poisonous.
It is reported that the owner of the logistics company has been detained by authorities in connection with the incident. However not many details were forthcoming about how the accident happened and whether the fatalities were due to the explosion and fire only, or did the toxic materials play any role as well ?
We can only speculate as generally the authorities in China are tight lipped and only once the official report is released, would we know the exact cause.
Yet another welding related fire-now in a nuclear plant!
As if we did not have enough of welding related fire accidents in conventional plants (read my last post on the issue here ), now we have a report of a similar accident in a Japanese nuclear plant.
Here is the incident reported by various agencies:
A fire broke out at a nuclear power plant in northern Japan on Thursday, injuring one worker but causing no radiation leak, the operator said.
Firefighters put out the fire about an hour after white smoke was spotted coming out of the reactor, which was already shut for a regular check-up, Tohoku Electric Power said.
“One worker sustained minor burns but was not exposed to radiation,” a company spokesman said, adding there was no leak to the outside environment either. The fire started at around 2:00 p.m. at the plant’s No. 1 reactor, which has been undergoing regular checkups since February, Tohoku Electric said.
Kyodo News Agency which first reported the incident said the worker was in a welding operation inside the building, and the filter in the air conditioning system might have caught sparks from the welding.
The plant is located in Onagawa town, some 350 kilometres (220 miles) north of Tokyo. The plant has two other reactors, which are operating normally.
The nuclear power complex, which suffered extensive damage in an earthquake last year, has been out of service and undergoing repairs.
The incident occurred just days after a Dec. 1-5 inspection by a team from the United Nations nuclear watchdog. The team of 10 experts from the Vienna-based International Atomic Energy Agency assessed safety measures designed to deal with the continuing threat of earthquakes.
I hope the investigation is completely impartial and gives us some better ideas to prevent such incidents in future. I know that the nuclear industry is a highly regulated and procedure-driven industry so this incident is shocking. Secondly, this is the second such fire in a Japanese plant (the earlier one was supposed to be because of an earthquake). However as usual, the investigation reports are pretty sketchy and certainly not as detailed as the ones from the chemical /hydrocarbon processing industry (Well, if they are I have not seen many in the public domain). I wonder what kind of combustibles are present in such installations and what kind of gas detection systems are used. Anybody from the nuclear industry who is reading this could be kind enough to throw some more light on this issue.
Comments as usual are welcome.
Explosion and fire at Buncefield Oil Storage Depot – Five companies to face prosecution
It is now almost three years since the Buncefield oil storage depot explosion took place and finally the authorities have declared, that they will be pressing criminal charges against five companies, ostensibly who have been found guilty of acts of omission.
For those of you who do not remember the case, here is a short overview. There were a number of loud explosions ( I mean really really loud-reportedly people in Netherlands and France heard it and it was recorded also a seismic event! ) and a massive fire at the Buncefield Oil Storage Depot in Hemel Hempstead, Hertfordshire, UK. Over 40 people were injured in the accident, fortunately there were no fatalities. Following the explosion, a Major Incident Investigation Board (MIIB) was established by the Health and Safety Commission, supported by the Board of the Environment Agency, UK.
There were a series of investigations and reports being published from time to time by this board and some of the significant findings were as follows -my summary of a rather long series of detailed reports:
a) No consequence analysis was done by any of the design engineers or safety experts, as to what could be the severity of the possible explosions of the flammable vapors generated from the petroleum storage tanks.
b) The level control loop, (that is supposed to control the level in the tank and prevent overfilling) on one of the storage tanks failed. It consisted of a Servo tank gauge connected to a series of valves. This failure led to overfilling and spillage of massive amounts of petroleum into the dikes surrounding the storage tank. Petroleum was being pumped in at a rate of about 550 m3/hr for more than three hours, yet the servo level gauge indication, failed to record any change at all!
However the DCS trend records could be salvaged and the above information was gleaned from them. Apparently the CCTVs were working and the footage showed petroleum overfilling and flowing into the tank dikes, but nobody was watching it at the time.
c) The overfill protection was provided by a point level switch which was supposed to be independently connected to an alarm/annunciator panel (separate circuit from the DCS loop). The panel had an override switch and it may be that the interlock was bypassed (no conclusive evidence since everything got burned in the subsequent fire, this may never be known). However it is warning to design engineers who think that by merely having a redundant level switch is good enough. Were there any common cause failures that both the continuous indication, as well as the interlock failed? Not known for sure.
d) The operators apparently did not notice anything amiss and neither was the control system very sophisticated, to tally the pumping rate into the tank to the rate of change of the level. Now here’s the cake. The pumping rate now increased to 890 m3/hr leading to the petroleum overflowing from the tanks, filling up the bunds and secondary containment areas and forming large vapor clouds. It seemed this occured because the inlet lines were common to all the tanks and the other tanks level indications were working, so the system diverted their inlets into this tank that appeared about half full (due to the faulty level indication). There must have been thousands of gallons of the stuff overflowing from all directions and nobody could notice anything! (Yes, it was about 3:00 am in the morning-but so what- were there no operator rounds of the premises or anything like that?- or it doesn’t happen on the night shifts at all?!)
e) Apparently the hazardous area classification which may have been done during the initial stages, may not have considered wind directions. The entire vapor cloud was carried across the road from the tank farm to an emergency generator building,about 100 meters away, where it is thought to have been ignited. The building apparently was not a classified (hazardous) location.
No doubt this entire catastrophic incident and the consequent investigations will have a major impact on how instruments and controls are designed and maintained in petrochemical/hydrocarbon processing plants, how operator alertness and awareness is important and so on.
More details are available at the Buncefield investigation site.
Note: All images have been sourced from the Buncefield investigation site and all copyrights belong to that site.
Sunrise propane explosion-could a little investment in good engineering and safety systems have averted it?
In Aug 2008, there was an explosion in a propane storage facility, located in the midst of a residential area in Toronto. There were two fatalities including that of a firefighter. The explosion was so huge it was very frightening and the subsequent fire was deadlier.
Here’s a link to the video on YouTube
http://in.youtube.com/watch?v=XCsNcwpYjUs
About 12,500 people had to be evacuated and the damage to property was extensive. The facility is owned by Sunrise Propane Energy Group, who are now facing a class action suit against them after the incident. An investigation into the incident has thrown up some probable causes, one of which is a truck-to-truck transfer of propane, which is not recommended for safety reasons.
Additionally a review of all existing propane installations in Ontario was ordered by the local government and the report is now released. It has reportedly about 40 safety and training recommendations. One of the recommendations is to review hazard distances and make that information available to the public at large. Unfortunately, most of the “public” everywhere (not just in Ontario) is not at all well informed about hazardous materials, their properties, safe distances and how to handle related emergencies.
(In fact, the general lack of easily available information related to hazardous area classification was one of the reasons why Abhisam Software, decided to come out with a download version of its popular hazardous area instrumentation training course at an affordable $99 price).
Well, coming back to the propane incident, it just shows how seriously all companies need to take storage and handling of hazardous materials, in case they wish to avoid fatalities, losses to property and open ended class action suits having potential liabilities of millions of dollars. A little investment in good engineering practices, safe designs with adequate safety margins, investment in training of operators and maintenance staff would have gone a long way in avoiding these huge costs later on. I believe there are a lot of reasons for the general deterioration of these standards in many companies, which include the following
- the mad cost-cutting of the last decade under the influence of the wall street gang (whom we now know to be thieves in disguise)
- the blind acceptance of these practices, by all and sundry in the management (along with some fat, it cut out a lot of the muscle and brain too)
- the overwhelming desire to match the “China price”
- the “profits before safety” philosophy-in fact the “profits before anything” philosophy
- the demolition of in-house engineering talent under the influence of again the same wall street ( they were overheads you see, not engineers with brains)
But I will stop my rant now and allow you to mull over all this.
BTW I wonder if the bean counters at these companies have understood all this in the right context (the importance of engineering, training and safety).
Comments are always welcome.
