Failure of UPS leading to turbine bearing damage

BHEL India has a good presentation on the importance of maintaining your UPS supply. In some of the incidents mentioned, the turbine bearing temperature increased to 140 Deg C and got damaged due to failure of UPS and auxiliary oil pump not coming in line afterthe turbine tripped. All failure modes of your UPS must be studied and corrective actions implemented. A UPS is a silent watchdog and if it malfunctions when it is required, it can cause a serious process incident. See the presentation in this link.

Combustible dust hazards - the explosions continue

The CSB has concluded that combustible iron dust has caused and explosion that killed one worker. The CSB mention the following:
"The first incident occurred on January 31 as two maintenance mechanics on the overnight shift inspected a bucket elevator that had been reported to be malfunctioning due to a misaligned belt. The bucket elevator, located downstream of an annealing furnace, conveyed fine iron powder to storage bins. The two mechanics were standing alone on an elevated platform near the top of the bucket elevator, which had been shut down and was out of service until maintenance personnel could inspect it. When the bucket elevator was restarted the movement immediately lofted combustible iron dust into the air. The dust ignited and the flames engulfed the workers causing their injuries. A dust collector associated with the elevator was reported to have been out of service for the two days leading to the incident.
The second incident occurred less than two months later on March 29 when a plant engineer, who was replacing igniters on a furnace, was engulfed in combustible dust which ignited. In the course of the furnace work, he inadvertently dislodged iron dust which had accumulated on elevated surfaces near the furnace. He experienced serious burns and bruises as a result of this second event; a contractor witnessed the fireball but escaped without injury."
Read the news release in this link.

The importance of properly designed back ups

A very good article by Bela Liptak about the back up systems at Fukushima mentions the following:
"The earthquake destroyed the electric power supply of the plant (the connection to the grid) which by itself should not have been a serious problem, because backup diesel generators (18) were provided. It seems they failed because they were not elevated and the 18-ft waves of the tsunami reached and damaged them. The reason for their being installed at low elevation was probably both convenience and concern for their stability. The destruction of these generators could have occurred because water entered the diesel fuel tanks and sank to the bottom because water is heavier than the diesel fuel. As the engine takes its fuel supply from the bottom of the tanks, water instead of oil reached it. It is also possible that the air intakes of the engines were not elevated and ended up under water. If either or both of these conditions existed, the engine could not operate.
The secondary battery backup (19) was of no use either because it was drastically undersized. It provided only about eight hours worth of electricity, while about ten times that would have been needed to supply the electricity needed for a safe shutdown. (It should be noted here that of the 104 American reactors, 93 are provided with only four-hour battery backups). Another problem in the Fukushima plant was the lack of automatic battery recharging. This could have been provided because the plant was still generating steam at a rate of about 5% of full capacity and, therefore, some of the turbine-generators could have been kept in operation.
No other backup was provided at the Fukushima plant. This is unfortunate, because electricity itself is not essential to cool the reactors. For example, if emergency cooling water tanks were provided on the roof, would have made it possible to charge water just by gravity, and if those tanks were properly sized, the accident could have been prevented."
Read the full article in this link

Transformers and process safety

Transformer fires can cause a process incident due to interruption of power to the unit. Give importance to the maintenance and fire detection and protection systems of your transformers. A good article by the US dept of interior mentions the following:
“The following devices should deenergize the transformer and trigger the transformer fire suppression system:
• Heat and/or fire sensors appropriately located near or on the transformer
• Manual discharge (control switch, pushbutton)
Depending on the type of sensors used and the details of the design, it may be desirable to require two sensors to operate before activating suppression to reduce false operation.
In addition, remote activation through the use of SCADA might be considered where operating practices permit and sufficient information is available to the remote operator.
Heat sensing fire detectors are the most reliable way of activating fire suppression for transformers. Techniques that should be considered include linear heat detectors (heat sensing cable) and infrared detectors. The appropriate method of detection is chosen when designing or re-designing the system.
Control system considerations include:
· Operation of the fire suppression system should deenergize the transformer to prevent water from discharging onto an energized transformer.
· Loss of power to fire suppression system pump motors, solenoids, and controls should be annunciated so the problem can be detected, diagnosed, and remedied.
· Activation of the suppression system should be annunciated and input to the SCADA system.
· Activation of the suppression system should block drains and pumping of oil-contaminated water from sumps into waterways.
· Activation of the suppression system should stop transformer fans and oil pumps that might feed the fire.
· Power the fire detection system from a reliable source, have continuous internal monitoring, and have sufficient output contacts for necessary alarm and control functions.
· Power the fire suppression system from a reliable source not affected by the loss of the transformer being protected.
· At unattended plants where high-volume deluge systems are retained, detection and control circuits should be designed to suppress the fire while reasonably minimizing the amount of water discharged. The purpose of this is to suppress the fire while limiting the risk of overtopping containment structures and contaminating waterways. It is reasonable to apply water for a limited time, temporarily shut down, and then reactivate water discharge to suppress any remaining fire. This might be accomplished through detectors that continue to sense fire, timers that cycle the system, or other means. In addition, high level detection in the containment structure is recommended to shut off fire suppression to prevent overflow. High level detection might be supplemented by video monitoring and remote deactivation through the use of SCADA.
Read the complete article in this link.

Identify chinks in your asset integrity program!

In 2004, a superheated steam pipeline in a nuclear plant in Japan ruptured, fatally killing 5 people. The rupture was 560 mm in size. The pipe wall at the rupture location had thinned from 10mm to 1.5mm. Apparently, the pipeline was never inspected since commissioning in 1976. Review your asset integrity program to ensure that there are no equipment or locations that have been skipped for inspection.In many companies having separate inspection departments, there will be a wealth of information, but soemone must be tracking the system to its logical conclusion. In today's scenario, with qualified and experienced inspection personnel in high demand, and turnover rates high in industries, it becomes imperative to have continuity in your asset integrity program. The chain is as strong only as the weakest link!
Read the article about the steam pipe rupture in this link.

Tank overflows and process safety

Many atmospheric storage tanks are provided with gravity overflows which lead to a sewer or drain. Gravity overflow sizing should be carefully done. An article written in 1983 by P D Hills is a good reference. Read it in this link.

Gaskets failures

Are you giving enough importance for training your maintenance personnel on the types of gaskets used at your facility and the method of fixing them? A good article by Jim Drago mentions that out of 100 gasket failures, 68 were due to insufficient load, 14 were due to wrong selection. Crushing, cavitation, erosion and other factors contributed to the rest. Insufficient load was attributed to improper installation, misapplication, poor flange design, and/or bolt selection and rotated flanges.
Read the article in this link

Pipeline integrity

Ever since the San Bruno pipeline incident, there has been lot of debate on pileline safety in the USA. A article mentions the following
"Pipelines are by their nature distributed and remote. Having sensors and analytics available to help identify pipes at risk would be a sensible strategy. Oil and gas companies are, in fact, investing in smart technologies for safety monitoring. As part of the 2011 Vertical IT & Communications Survey conducted by IDC in January, 2011, which included 90 North American oil and gas companies, 42% stated that they would be investing in smart technologies for safety monitoring in the next one to two years. This is not surprising given the importance of safety in the upstream side of the business. But in midstream, there are a number of questions still to be answered. The major risks to pipelines are corrosion, digging and failure of materials. Is sensing technology available that can identify these potential risks to pipeline integrity? Sensors in remote locations should not have significant power requirements and should be able to be powered by long-life batteries. Are these sensors now available? Then too, is the telecommunications infrastructure available to support bringing the data back for analysis? We welcome your comments"
Read the complete article in this link..

Process safety - what you don't see will get you!

A news article mentions that an unexploded German mine from World War Two was found near the BP Forties oil pipeline in the North Sea. The article also mentions that there is no immediate threat to the pipeline and the mine will be removed after a shutdown of the pipeline for a few days later in the year. The article reminded me of many chemical manufacturing companies taking over other organizations without doing a proper process safety due diligence. While financial due diligence is no doubt important,it becomes imperative that you also conduct a process safety due diligence to find out if you have any surprises in store!! The due diligence should cover the technical as well as the process safety cultural issues. Look before you leap and you can avoid an incident!

Fukushima and Bhopal

I have been reading with interest the interest in nuclear safety in Indian nuclear reactors after the Fukushima incident. I was wondering that if Bhopal had happened today, would the implementation of laws improve? While the West has learned from Bhopal and implemented stringent laws,we in India are yet to focus clearly on chemical process safety management. With the chemical industry set to boom in the next decade, should we wait for another Bhopal to occur before actions are taken? The current focus on process safety in India is still largely on a reactive basis. While large organisations have proactively and voluntarily taken up PSM, it is the medium and small scale organisations that are not prepared. Many of these units handle highly hazardous chemicals. It is time that the large players in the Chemical Industry start a mentoring program free of cost to enable the small and medium scale players to improve process safety. It is good for the whole industry.

Turbines and fires

According to a 1985 EPRI report, "Turbine Generator Fire Protection by Sprinkler System," by Black and Veatch, a survey of 175 generator related fires and 33 hydrogen explosions from the period 1930 to 1983 indicated that of the 119 fires involving lube oil, 39 fires occurred at the turbine bearings, 16 fires involved lube oil piping, 14 fires occurred below the turbine deck, and seven fires involved the lube oil reservoir. The exciter has also been identified as both a lube oil and an electrical hazard (seven electrical fires and two oil fires).My experience indicates that this statistic is valid even today.
Piping joint leaks, view glass leaks, piping cracks due to vibration etc all cause lube oil to leak, causing fires. These fires can stop production for quite a while as not only equipment but control and electrical cables will also get damaged. A leak of lube oil from a lube oil pump discharge line causes an atomised spray of lube oil and the source of ignition could be an uninsulated steam line. I have witnessed a major fire caused by a lube oil line leak and the damage was enormous. Train your operators to report unusual vibration, minor leaks and ensure your asset integrity program covers the lube oil system.

Bhopal disaster - Police Chief's account

I met Mr Swaraj Puri, the then Chief of Bhopal Police when the Bhopal gas disaster occured, at an international conference on Bhopal gas disaster at IIT Kanpur in 2004. He recounted the horrors of that night and the difficulty he and his men faced in the aftermath of the tragedy. I chanced upon his website where he mentions all the details of that fateful night in December 1984.He mentions the following:

"The Shortcoming and the Lessons for the future
One of the first thing that struck us when the gas leak took place was our total lack of preparedness and ignorance about how to deal with such a situation.
The medical fraternity and the chemists were unaware about the effects of Methyl Isocynate on humans and also the medical treatment to deal with cases of exposure. The Chief Medical Officer of the Union Carbide Factory initially deemed MIC as only an irritant! Since the gas was of the cyanide family, Sodium Thiosulphite was administered as a probable antidote. Specifically the factory was to blame because:

• The plant did not give vital information about the storage and handling of hazardous and dangerous materials.
• Effect of MIC on humans and the antidotal treatment was not known to the medical fraternity and such knowledge if available was not disseminated to the emergency services.
• There was a lack of appreciation of disaster management within the Government and also inadequate co-ordination between the factory and the emergency services.
• There was an absence of proper warning system in the plant. No practice drills were ever held.
• Union Carbide itself had limited data on MIC and probably had never anticipated the 'worst case scenario
• Poor plant maintenance practices. Inventory of vital spares had been depleted.
• Exodus of some of the experienced engineers and operating personnel from the plant.
• Economy measures, overriding safety concerns.

Apart from these, we noticed some other difficulties all inextricably linked up with the developmental process in the country.

• Densely populated areas around the plant. Often shanties / slums come up on vacant areas surrounding the factories greatly increasing the danger of loss to human life. Urban planning authorities are powerless, there is an absence of political will since much of the problem is caused by the poor flocking to the cities in search of employment.
• Absence of a proper road network, rescue workers had to move on foot through densely populated areas
• Poor communications, though things have improved now.
• Lack of effective emergency medical facilities.
• Inadequate transport for emergency evacuation, even today the infrastructure is woefully in adequate.
• Cattle living in residential areas, a peculiar Indian problem, not there in the metros, but very much in existence in other urban centers.
• People sleeping on pavements/ railway platforms.
• Unidentified dead bodies. Creating difficulties in identification of religion and also medico- legal problems. Many could not be identified. They were photographed, given numbers and cremated/buried
• Along with humans a large number of animals, mostly cattle perished in the disaster. Their disposal became a serious health problem. There was a threat of an epidemic. Cranes and bulldozers had to be put in operation to remove the dead animals and then bury them in a mass grave disinfected with tonnes of bleaching powder.
• Administration collapsed with key functionaries running for their lives instead of manning key positions
• Relief operations became difficult as the disaster caused total enervation in those entrusted with emergency relief.

SUCCESSES
Not every thing was a failure, the Police and the Medical Department with whatever meager resources at their disposal put up a tremendous immediate response. NGOs and social service organizations moved in immediately to help in the relief efforts. Local media was extremely helpful in scotching rumors and in disseminating essential information. Even the international media cooperated. The most affected area included the Bhopal Railway Station, the station master perished from the effects of the gas but the railway personnel immediately alerted the concerned, regulating the movement of trains and thus saving many lives.
FOR THE FUTURE 
The Administration, the Police and other essential services must know the location and exact nature of any hazardous chemical that is stored by any industrial establishment. The procedure to be followed in case of exposure and the antidotal treatment should be known to the aforesaid. Adequate quantity of antidote should be available with the industry which stores such hazardous chemical.

1. The people living in the vicinity should be made aware of

• the chemicals being stored
• The likely symptoms and antidote
• Emergency procedures which should be also rehearsed
• Nearest medical facilities
• System of contacting the Factory management
• Sources of transportation for emergency evacuation and the availability of ambulances.
• Rumors and unfounded fears should countered by local Radio and TV
• NGOs and other Voluntary Organizations capable of providing help should be involved in the disaster management process and be listed and known to the administration as well as the residents of the vicinity
• Residents living in the vicinity should train with the emergency services"

I still do not believe that we are ready for handling another similar disaster. Read Mr Swaraj Puri's account of Bhopal disaster in this link.