Case Studies on Some Industrial Accidents: Lessons to be Learnt by Practising Engineers: Part-1

Case Study-1

A Gas Leak Accident that Killed Seven!

This incident happened in a large integrated steel plant in India. In integrated steel plants (ISP) world over, iron ore is first converted to molten iron called hot metal in a chemical process reaction vessel commonly known as the Blast Furnace (BF). ISPs normally have many BFs for producing hot metal all normally working in parallel so that they achieve their targetted production levels. Hot metal production in an ISP is typically to the tune of a few thousands of tonnes per day or a couple of million tonnes per year.

Iron ore is a natural mineral containing oxides of iron and other impurities such as oxides of silicon, manganese, magnesium, calcium, etc. It is nothing but commonly available red soil having the iron content a bit higher for economical extraction of iron. For separating the iron, the iron oxide needs to be melted and reacted with the reducing gas, carbon monoxide freshly produced by the action of oxygen in air with a carbon rich raw material such as carbonized coal commonly known as coke. All these reactions continuously take place in a vertical semi-fluidized bed reaction vessel called the Blast Furnace (For more about the Blast Furnace process of iron making see this wiki article).

Waste process gases emanate from the top of the Blast Furnace, called the BF Gas, which is nothing but the excess air carrying much of the gaseous reaction products such as Carbon monoxide, Carbon di oxide, Hydrogen, etc together with the dust generated during the vigorous exothermal reaction in the furnace. This gas is very hot and contains useful chemical energy due to the presence of Carbon monoxide and Hydrogen. Conventionally, in the ISPs this gas is further cooled and removed of the dust in gas cleaning plants (GCP) for use as a low calorie fuel gas elsewhere in the steel plant. This BF gas is highly toxic because of the presence of Carbon monoxide.

The dust laden BF gas that comes out of a BF is cooled and cleaned in a GCP by spraying water over the gas in closed scrubber vessels. The water used for cleaning the gas entraps the dust present in the gas and becomes a slurry which is then treated in a wastewater treatment plant (WWTP) system. In the WWTP the waste water (effluent lean slurry) is settled for removal of suspended solids, cooled and the clarified water is recycled back for the scrubbing process in the GCP using pumps installed in a pump house.

Blast Furnaces are continuously operating chemical reactors intented for extractive metallurgy. Once it is built and commissioned, it is fully stopped and taken out of production service only for capital repairs. Such capital repairs are done after several years of continuous production. However, minor hot repairs are also carried out periodically by keeping the furnace hot, but without the full fledged production. All repairs are planned with the least shutdown periods, to keep the production losses to the minimum.

A working BF containes several hundreds of molten metal and semi finished raw materials inside its vertical shaft and its bottom belly. This is kept hot and reactive with the action of huge volumes of hot air blast that is is blown inside through the huge bed of raw material stock contained in the furnace shaft through nozzles called tuyeres. The air blast is the most vital process of the blast furnace that is accomplished through large air blowing machines. 

Besides, large quantities of cooling water is continuously required to cool the BF shell. Any failure to supply the air blast or the cooling water can cause serious damage to the BF. If air blast is stopped for some time there is the danger of the molten iron and molten slag getting solidified in the furnance that could cause irrepairable damages. Similarly, stoppage of cooling water can cause the BF shell made of steel plates to melt down. 

ISP operators and management consider BFs as the most critical production facility and ensure all they can to keep the BFs in operation through out is operating life till it is taken out of service for any planned repair period.

A BF plant is a complex conglomerate of many systems, equipment and components, operated and maintained by managers, metallurgists,engineers and technicians who are teamed up in various functional departments and sections. In their anxiety to keep their own systems under top priority, these teams often forget to understand the role of the other supporting  systems and the teams that operate and maintain them. 

Any maintenance to the BF system needs some time of some shut downs to some of the working equipment and systems which may lead to some production loss. Hence, production oriented managements usually keep building the pressure on the various teams to have their maintenance activities completed by taking the least possible time. 

Such pressures often cause some engineers to postpone some maintenance functions which they deem as non-vital to some later maintenance time, only to keep them postponed further in a similar way. Such management pressures also cause some engineers to neglect or by-pass some systems which they consider as irrelevant. Lack of proper understanding of the plant systems by new engineers and teams enhances such risks. This is because the old ISPs have  production facilities with operating life exceeding several decades.

The ISP where the accident occured have been operating six BFs in parallel with many common facilities such as the pump house, the WWTP, the Air Blower Station, etc. There were independent GCP facilities for each of the six BFs, but the waste water treatment facility and the pump house that circulated the water were common to all. There existed one group of pumps that recycled clarified water from the WWTP to the individual GCPs through a common header pipeline. These pumps were located in a common pump house which was located sufficiently away from the BFs and their GCPs. The pumps were located in the dry-well of the pump house which was a few meters below the general ground level.

There were three pumps in this group and normally two were kept in operation and one was kept as a standby. Each of the pump discharge pipes connected to a common collector pipe kept at the pump floor, through their own isolation valves and non-return valves. A common pipeline connected to the common collector pipe distributed the clarified water to all the six GCP scrubbers. Individual branch pipelines supplied water to the scrubbers where the water used to be sprayed to the hot BF gases for cooling and cleaning through various kinds of nozzle systems. The piping system had several motor operated and manual valves for controlling and isolating the water supplies to the GCP systems as per requirement.

The GCP scrubbers were the process equipment where the BF gas and the water interacted. As the water had to spray over the gas, the water pressure was kept much higher than the gas pressure.

Several departments worked to keep the BF production and maintenance operations to go on uninterrupted. There were the BF department with their own sections responsible for the mechanical maintenance, electrical maintenance, instrumentation maintenance and other supporting departments such a the Energy Management Department responsible for the GCPs and the Water Management Department responsible for the pump house, the WWTP and the main water supply pipelines. The staff and engineers of all departments worked in shifts on a 24x7 basis.

Some operating personnel of the Water Management Department had been aware of a minor leak in the common collector pipe located in the main pump house to which the three GCP supply pumps were connected, for some time. The leak had happened in the lower side of this fairly large pipe with a diameter of about 900 mm. This pipe piece was supported on the floor of the pump house and there was hardly any space between the pipe bottom side and the floor. This restrained the operators and the shift managers to assess the real condition of the pipe. While the pipe was quite okay on the top side, there was some corrosion at the bottom side and there was some pin-holes from which water had been leaking.

In the last several decades, this pipe piece was never replaced during any maintenance and the concerned department knew about its old age and probable deterioration due to ageing and corrosion. The pipe bottom was specially vulnerable to external corrosion as this side was difficult to be painted due to the small working clearance. Besides, this side was exposed to water accumulations in the pump house floor that happened occassionally due to various reasons. This also was one of the reasons for the probable external bottom side corrosion of the pipe.

For replacing this pipe piece, the Water Management Department needed to take a shut down to the GCP water supply main header pipe which invariably affected the production from six BFs. The production managers over the years had developed a type of technical  superiority in all decision making due to which it was difficult for the Water Management Department to convince the top authorities about the necessity for a production shut down for replacing a small length of old water pipe. The engineers of the Water Management Department had developed a submissive attitude over the years which prevented them to talk authoritatively about their technical requirements and convince the top authorities of the steel plant. They had almost developed a withdrawn attitude towards their professional vigilance  to  critically study the various kinds of risks involved in their functions!

The inter departmental meetings, for quite some time, had been stressed towards achieving production targets and better production performances with attention towards removing bottlenecks. Perspective assessments and critical analysis of risk scenarios had undergone a decline.

This caused the top officials of the Water Management Department taking temporary actions for rectifying the leak, instead of reporting the issue to higher management authorities with a proper risk assessment study to convince the authorities for an immediate shut down of the BF-GCP systems for taking up the work of replacing the leaking old water pipe. The temporary leak plugging acts done by the department by welding etc further aggravated the condition of the leaking pipe.

And within another couple of days, in one shift, all of a sudden the pipe ruptured. Water splashed out from the rupture and the GCP water supply pressure dropped. The shift personnel of the water management department informed their seniors and the matter got communicated to all the other concerned engineers and managers of  the Energy Management Department and the BF Department. The heavy leakage of water from the ruptured pipe was now flooding the pump house and the pumps had to be stopped to prevent flooding. Those concerned officers, engineers and operating people of the steel plant rushed to the pump house to physically assess the rupture in the collector pipe.

But without them ever realizing, a major tragedy was about to happen shortly. As the water pressure in the GCP water supply pipe decreased due to the rupture and the subsequent pump stoppage, the water in the pipe line began to drain out through the rupture as the rupture point was the lowest point. Soon the water in the supply main got emptied and the toxic BF gas began to fill the water pipe from the scrubbers and began to leak out through the pipe rupture in the pump house.

Carbon monoxide is an odorless gas and a swift acting toxin. The pump house is a closed enclosure and the toxic gas was getting mixed with the air in the pump house. This posed a two fold danger. First the pump house became a toxic gas chamber. Any one who inhaled now got affected by carbon monoxide with imminent lose of consiousness and possible death. Secondly, the pump house was getting an explosive mixture of fuel gas. Certain low concentrations of monoxide gas with air is highly exlosive and it could explode like a bomb causing major damage with a minor spark any where!

The people who rushed to the pump house now was getting affected by the toxic gas and they were simply falling down unconscious. It took others who followed those went earlier down to the pump house some time to realize what was happening. And when they realized it, a number of persons were already affected. Fortunately, the rest of the engineers realized what was happening and they could take immediate preventive measure that could save the pump house from exploding!

Several people got affected and about seven lost their lives due to gas poisoning. It took the steel plant a few days to restore normal production! What production they obtained earlier by post poning a planned shut down all wiped out now due to this accident.Perhaps the loss was much more including precious lives of people!

A series of enquiries followed. Some by the statutory authorities, some by techincal empowered groups of the company. All enquiry committees and commissions brought out their own findings and suggestions. While the technical cause was pin-pointed, the committees apparently failed to recognize the root cause of the problem- the cumulative effect of  technical management errors that had been happening for a long period!

I will now discuss some of these errors that keep happening in Indian process industries which most of the Indian engineers assigned with the task of factory management routinely seem to ignore or do not consider as some thing important to be addressed properly:

1. Indian engineers are not very much comfortable with the concept of unit wise operation of multiple process units and systems. If there are more than one process equipment or system for achieving higher production, the Indian engineers quite often force the plant suppliers and designers to interconnect those systems for higher flexibility of operation and maintenance. For example, it was much safer in the above mentioned case to operate and maintain each of the BF systems as  self contained individual systems instead of an interconnected system of six BFs. The interconnections enhance system complexity for engineers to understand and comprehend causing new comers be confused about all the functions of the plant systems. This causes neglect of some parts of equipment and systems, especially those that are to be operated only during exigencies! Whenever, a plant accident or breakdown take place, the subsequent actions would be to have more interconnections and more stand by units which enhance the system complexity rather than reducing it in actual practice. 

2. Indians quite often are not very comfortable with record keeping. They seldom make efforts to keep all technical drawings concerned with the plant process and systems. Even if such drawings and documents are available, hardly any effort is made to ensure that all concerned engineers study those drawings and documents carefully and comprehend those fully.

3. Design engineers and plant operation and maintenance engineers work in isolated pockets. They are seldom encouraged to understand the philosophies and technicalities involved in each others' area of work. This often causes erroneous assumptions and subsequent errors. For example, in the case discussed above, the original design engineers had provided certain provisions of water sealing and siphoning arresters in the pipelines that prevented any gas to escape through the water lines when water got emptied in the pipelines under rare situations as had happened. But many such systems got removed or erroneously fixed in later years as the concerned maintenance engineers did not understand their functions or principles of operations.

4. The steel plant management had adopted a system of inter departmental transfers of engineers without ensuring availability of experience and competence of engineers and technicians with regard to their own area of work. This had caused experience vacuums in many areas with the teams handicapped with understanding of technical issues and technical communications. In some cases, the junior engineer felt difficulty to communicate a problem to his senior as the senior had less experience in the field and vice versa. In the case discussed, such a situation had caused the concerned people to foresee the problem in advance. Had there been the required experience and competence at all levels, this problem would have never got escalated to a major mishap like what had happened.

5. Of late, the Indian managements of technical facilities are more and more becoming non technical in attitude and nature with the top managements losing their capacities to understand the complexities involved in technical works. As finance, marketting and other non technical fields are becoming more and more important at the board levels of decision making, the voices of technocrats in companies are getting diluted and they no more get any chance to make the non technical board members to understand the technical problems. This causes the top technocrats to either discard their technical thinking and behave like non technical persons. They in turn discourage technical issues to be discussed at top levels. Real technical and engineering problems now get reduced to lower level issues. This seriously enhances the technical risk levels of Indian process plants. This attitude then percolates downwards and adversely affect the technical thought processes of all engineers working in Indian factories and process plants. Indian engineers working in processing facilities of companies now seldom get any reward for proactive or creative professional thinking. On the other hand, erroneous technical conclusions and erroneous punishments to engineers are on the rise now in India making professional engineering and technical work something not preferred by brilliant engineers.

I hope eminent engineers from India would open up their minds to express their thoughts and comments on the above.

Observations on the Working Styles of Two Indian Public Sector Chief Executive Officers !

What I am going to narrate here are two episodes that happened during some years ago during my service as an engineer in a large Indian Public Sector Company. The purpose of narrating this is to highlight the importance a Chief Executive Officer in making a difference  to the performance of the business organization. Those who are capable of understanding can very well differentiate the leadership traits that made the difference to the organization on a long term perspective from some apparently negligible actions of theirs.

For obvious reasons, I would not name the persons or the organization.

This may be taken as a real life case study in management !

The company is a large metallurgical process industry (to be more specific, a large integrated steel plant) employing nearly 50,000 people, of which nearly 2500 are qualified engineers. The engineers employed by the company are from various engineering disciplines as far as their educational backgrounds are concerned. The company's recruitment policy is such that it selects fresh engineers from the academic institutions on a pan India basis based on a stringent recruitment process. Such engineers are placed in the technical management cadre of the company. It is from this cadre that the company later draws its Chief Executives and top management personnels.

Though it is a government owned Public Sector Unit (PSU), the promotions and career growth prospects in this company are not similar to the government service. In the Indian government service, seniority is the major determiner in deciding promotions of an officer from a particular cadre. Though the Indian PSUs initially followed the government rules, the career rules in them kept on changing to their convenience when the government began vesting their Boards with more and more autonomy. As such, the Indian PSUs do not have any uniform career policy, except that they follow some mandates from the government in deciding the pay and perks of the employees.

Now let us come back to the two chief executives of this PSU. For convenience let us call them Mr.X and Mr. Y. The former was the Chief Executive Officer (CXO) of the same company more than a decade earlier to the latter. Both of them joined the company as fresh management trainee recruits, Mr X joining the company during its formative years and Mr Y joining the company later during its prime performance years.

Mr. X had his education from a premier national institute while Mr. Y had his engineering education from an institute not of that prominence. Both these gentlemen incidentally hailed from the same Indian state. Linguistically and culturally they had similar backgrounds. Mr. X was a metallurgical engineer while Mr.Y was an electrical engineer. During the initial two decades of their career both worked as first line executives in two major production departments of the same company.

Mr.X had an opportunity to work in another PSU in the General Manager and Director levels for a few years before he was selected and placed as the Chief Executive of his parent company while Mr Y worked in the same company , though he held different responsibilities in a few other departments.

When Mr. X took charge of as the CXO, he came after a gap of nearly a decade and the younger generations of officers never knew him. Most of his batch mates and seniors where now in senior levels in the company holding various positions but subordinate to him. The company just at that time had completed a major expansion plan and was just waiting to get the benefits of the massive production capacity expansion. Unfortunately, many of the new production units were failing to produce in the acceptable levels due to many technical problems of a new kind which the company never faced earlier in the old production units.

For example, the new Steel Melting Shop with latest steel production facilities was not able to sustain its production because of a technical snag on its gas cleaning facility. The latter came up with latest technology and was supplied by a reputed European company. Though the plant had been commissioned, the production of steel could not pick up because the gas cleaning plants would break down so soon. Unless the company produce the crude steel in this department it cannot possibly make the saleable steel in the other production departments! Capital employed by the company in the billions was not making any returns !

The company had trained its operation and maintenance engineers in the new technology by sending scores of them to the foreign countries from where the technology was procured. Besides, the experts from the foreign suppliers and the consultants were all breaking their heads to solve the problem.

But the problem was not getting solved. More and more experts were requisitioned from other countries as well and their suggestions were getting tried one by one. But the problem remained unsolved.

The CXO was spending hours daily in meetings with high level Indian and foreign teams to resolve the technical problem. But nothing was happening.

While the big efforts were on, the CXO did another thing. He devoted some time to discuss the issue with some of his personal friends and earnestly requested them to find any one in his large organization who could be of some help. That informal request from the CXO caused a silent 'people' search within the organization, not necessarily connected with the problem. The effect was that one day, my boss requested me ( a very junior level engineer at that time and not connected in any way to steel production) to visit the new Steel Melting Shop and study the problem independently and suggest some solution if I could.

So, I visited the new shop. I knew none there. There were big actions every where in the huge production shop which was built and commissioned just recently. There were high level 'experts' and engineers from many countries in dynamic activities trying to find out some solution to the problem. Some actions of modifications were going on as suggested by some experts. The plant was not on production mode !

With difficulty, by spending some time in understanding the process and the technology by glaring at the massive pieces of equipment connected by massive pipelines and cables and by discussing with some shop personnel here and there, I studied the problem. I thought about the whole process and the systems with a rational but unbiased mind.

Then it struck me. I found the possible reason for the gas cleaning plant failing frequently ! I could also guess the possible solution ! One of the huge pipes was getting chocked with a rock like formation which was not prone to conventional cleaning within days the plant is put to service. And the chocking location was different every time.

The solution what I found involved replacing a length of pipe of the gas cleaning plant with a smaller diameter pipe. But my predicament was that an external expert agency had also identified the problem to the same pipe and they had recommended for going for a higher size pipe. In fact one higher size replacement had been tried without any positive result and the same agency had suggested for a still higher size and work was in progress for effecting this new replacement. My technical logic on the other hand , involved changing the pipe to a much lower size than was originally designed by the foreign technology supplier.

When I told this to my boss, he discouraged me. He even challenged my knowledge and experience. How can an young Indian engineer could possibly solve such a 'big' problem so easily, that so many teams of foreign experts could not do so far ?

That was his simple logic !

But perhaps due to some other reasons he somehow decided to forward my suggestion note to higher ups. As the problem was so serious to the company, my suggestion somehow reached the Mr.X, the then CXO, who instead of throwing it to the dust bin, instructed the next in command to personally discuss the matter with me and proceed to implement it if I was found confident !

Soon, the big bosses of the company came to meet me. Some were apprehensive, but some others were willing to buy my suggestion. Soon the CXO took the decision in my favour and ordered to implement my suggestion under my guidance. The ongoing work (implementing the suggestion of the external expert agency) was stopped and the work as suggested by me was taken up, instead.

The work got completed and the plant was started. Though there was an apprehension from many people that the gas cleaning plant would fail in the first attempt itself due to the drastic change from its initial design, they proved wrong. 

The problem was solved for ever and soon the new shop began producing steel and production picked up momentum soon after. This one success catapulted my reputation as an engineer and soon I was recognized by the CXO and the top management team as an expert of the organization who could be consulted for other problems as well.

Years later, Mr. Y became the CXO. We knew each other personally. The same company  was in peak production when he took charge as the Chief. But now the issue was maintaining the plant in that performance levels. The equipment and the people are to be kept in top form ! Unlike the former CXO, this individual was a popular figure and he had personal touch with many junior and senior level engineers and officers of the company before he was elevated to the top post.

But when he became the CXO, he decided it the best for him to keep aloof from all. Perhaps he thought that would be the best policy to maintain his 'gravity' as the Chief !

He created a large CXO Secretariat filled with a large team of officers to assist him. No one was normally allowed to meet the CXO, unless approved by his Secretariat.

He was a person in regular talking terms with me before he got elevated to the top positions. He was  from a management trainee batch a couple of years senior to mine. But professionally we belonged to a different technical discipline. But he knew about me and the areas where I was considered in the company as an expert for the past many years.

When he took charge as the CXO, a major plan was going on to modernize a major production facility of the company for crude iron making with massive investments. This  involved some major changes in the technology which were proposed by some external consultants and suppliers.

While the plans were discussed at the CXO level, Mr.Y felt that one the new technologies which was being proposed need to be checked up for its suitability by me, as he knew vaguely the experience and expertize that I had in this field. Perhaps he asked some one in his Secretariat to get me involved but they did not do it that time. His management style had somehow made his Secretariat capable of deciding what the Chief should see and decide !

Sometime later, when we met accidentally in another forum, he tried hard to discuss the matter with me, but he could not spell out the technical issue properly as was not able to recollect it fully.

The plans of modernization went ahead and got implemented and the some commissioning bottlenecks were experienced for the newly modernized facility. Again  in some other top decision making forums Mr Y desired that I should be called and my opinion should be taken before one of the new systems which came up as a new modification is actually put to use. This time perhaps he desired it because of the difficulties felt in getting this new facility commissioned together with the larger production facility that got renovated. Again none actually took him serious, though I was informally informed of this development by another top officer of the company who is privy to the high level meetings chaired by Mr.Y.

I was not involved in the said project in any way. Yet, I felt that this was some thing important and I should have a look in to it for the greater interest of my company. So, I studied the whole issue independently and found that the new facility which was going to be incorporated was to create a greater technical problem later, seriously affecting the plant life and productivity. Technically, the new system which was going to be installed was not at all required and if incorporated as such was going to cause a major bottleneck after some time, instead of having the benefits as envisaged.

So, I met the top officer who communicated the issue to me and informed him of the consequences the company would have and gave my technical advice of not incorporating this new system. But this officer informed me that it was such an issue that he would not be in a position to inform Mr Y. He advised me to meet the Chief Executive, if possible. So I made attempts to meet him, but his Secretariat denied me permission by citing various reasons of pre-occupation and busy schedules of Mr.Y. It is to be remembered that they knew our previous relations and about the desire that he expressed to get my technical views.

Then the last thing left to me was sending a direct message to him. I did that too, hoping that the persons in his Secretariat would judge that an important one and bring that to his notice.

Apparently that did not happen. Shortly, the new facility was commissioned. I remember telling a few of my colleagues about the blunder made and the possible failure of the production facility in the near future.

It happened the way I thought. The iron making facility which was renovated by spending huge amounts have been spending millions again and again to off set the problems that kept developing. Major investments are being done and productivity is affected adversely. The facility which was created to produce crude iron trouble free for at least a couple of future decades is failing every now and then. Much money and efforts are spent to keep it running with frequent shut downs and  repairs.

During the short period of about two years as the CXO, many apparently invisible acts of Mr.X made the company fare very well in the next many years. His acts had a long term positive effect. I have knowledge of many such things and in a few other cases also I was personally involved.

Mr.Y remained in the seat of the CXO for nearly four years. He got a good working company to manage. But the way he performed his function as the chief executive mostly caused long term negative impact on the company. Though he had left the position, his style of management had set in a negative slide for the company.

What was the personality trait that made it possible for Mr.X to effect a better future for the company?

What was the personality trait of Mr.Y that caused the company to slide down ?