An I pad manufacturing facility in China has experienced a possible magnesium dust explosion injuring 16 workers. The incident is being investigated. The news article mentions the following:
"Currently, little is known about the cause of the explosion. However, reports by the local Chinese media have stated that the explosion was caused by the ignition of magnesium dust. Magnesium is a highly flammable metal that is commonly used in industrial polishing processes. As reported by CNET, magnesium is also used in the manufacture of fireworks and flares. Faulty or deficient ventilation systems at the Chengdu plant may have allowed magnesium dust to accumulate in the atmosphere. If that was the case, even a small spark would have been enough to trigger an explosion". Read the news article in this link
May 22, 2011
May 21, 2011
Learn from these process incidents
The Industrial Disaster Management Information System of the Government of Gujarat has given information about 15 process incidents. Learn from these incidents as they seem to be occurring with alarming frequency in other places too. Read about the incidents in this link.
May 19, 2011
Are we prepared to tackle a major disaster?
A news item in the Hindu newspaper indicates that a mock drill that was held in Andhra Pradesh had shortcomings. The report mentions that
"During the exercise, it was found that except fire, police, revenue, medical, and civil supplies departments, the other departments did not respond to the expected level to the crisis. According to a senior official, there was zero response from the Greater Hyderabad Municipal Corporation (GHMC) stating that the accident area did not fall under their jurisdiction.
“The officials concerned failed to respond even after information was passed on to Hyderabad. Will their reaction be the same if such an accident occurs in reality?” asked an official. He also admitted that many of the district officials failed to participate in the exercise and that there was a need to check their preparednes".
If after 27 years after the Bhopal disaster, we are still not prepared, I wonder what the situation will be when an actual disaster strikes!
Read the article in this link
May 17, 2011
Design your scrubbing systems properly
Scrubbing systems are your last line of defence. Ensure that adequate redundancy is provided to ensure that the system will work properly when needed. In an incident the CSB investigated, excess chlorine vented to a scrubber where it completely depleted the active scrubbing material (caustic soda), over-chlorinating the scrubber. The resulting decomposition reaction vented chlorine vapors to the atmosphere. Hazardous emissions continued for about six hours and led to the medical evaluation of five residents and 11 police officers, and the evacuation of 1.5 square miles. Read the CSB recommendations in this link.
May 15, 2011
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.
May 14, 2011
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 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.
May 13, 2011
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
"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.
“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.
May 11, 2011
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.
Read the article about the steam pipe rupture in this link.
May 10, 2011
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
Read the article in this link
May 9, 2011
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..
"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..
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