STARTING MY 11TH YEAR OF BLOGGING!

Dear Readers,

Thank you for being with me for the past 10 years since I started my blog. 

1800 posts, 325000 views, about 800 incidents and many of my readers spreading the information from the posts through process safety one point lessons within their own organizations...I am still far from satisfied. My mission in life has been "Preventing another Bhopal" and let us not rest till we have achieved it. How can you help? By the following steps:

1. Never be silent when you see something going wrong - it could be a decision that is not in the interest of process safety - speak up!
2. Share past incidents (internal incidents and external incidents) and their root causes, with all your colleagues - we see the same old incidents repeating
3.  As an engineer, be ethical when taking decisions and do not take decisions because they please the boss
4. Update your technical knowledge continuously
5. Do not be carried away by all the technologies that vendors try to sell you. Thoroughly study them and employ only those technologies that are useful to you. Don't get carried away by Jargon.
6. Wear your engineering hat always, even when you go up the management ladder.
7. Be aware of normalization of deviations around you. Report them and determine the root causes. You work in a chemical plant. You and your colleagues should not have the misfortune of seeing people die before your eyes because of an incident....

I end by quoting Robert Frost, "The woods are lovely, dark and deep, but I have miles to go before I sleep"

The working of a flame arrester

 

Process safety beacon on flame arrestor

 https://www.aiche.org/sites/default/files/cep/20160420.pdf

Can a flame arrester element be made of a non metallic element?

Flame arresters are often provided on vent lines in atmospheric storage tanks storing flammable materials. The principle of operation is by cooling the flame and extinguishing it before it reached the inside of the tank. As the flame travels through the element, it is exposed to a large area of the element, which can be folded meshes etc. But do you know that the element inside does not necessarily have to be metal? The flame arrester element itself experiences very little warming, because it is subjected to a high temperature for a very short time. Heat transfer is initially due to convection/diffusion and then later due to conduction after flame has been extinguished. Hence non metallic elements like PTFE can be used to avoid plugging. See one vendors catalogue here https://www.protego.com/products/detail/FA-I-PTFE.html

Note: This is for information only.

CSB releases airgas safety spotlight

 https://www.csb.gov/csb-releases-airgas-safety-spotlight-/

INCIDENT DUE TO BLOCKING OF ISOLATION VALVE

 In 2008, facility workers in the US closed an isolation valve between the heat exchanger shell and a relief valve to replace a burst rupture disk. Maintenance workers replaced the rupture disk on the day, however, they forgot to reopen the isolation valve. The next day, other facility workers closed a block valve to isolate the pressure control valve from the heat exchange so that they could connect a steam line to the process line to clean the piping. The steam flowed through the heat exchanger tubes, heated the liquid in the exchanger shell, and increased the pressure in the shell. The closed isolation and block valves prevented the increasing pressure from safely venting through either the pressure control valve or the rupture disk and relief valve. The pressure in the heat exchanger shell increased until it violently ruptured.

CONFINED SPACE FATALITY

https://www.gov.uk/maib-reports/entry-to-enclosed-space-on-fishing-vessel-sunbeam-with-loss-of-1-life

Do not depend on remotely operated valves for isolation for maintenance work

The two incidents below highlight the fact that you should not depend on rmotely operated valves for isolation during maintenance activities. ROV's are meant for use only during emergencies to prevent a major loss of primary containment:

1. A bolted joint was opened for maintenance on a pump but reliance for isolation was placed on a remotely actuated valve. The valve was inadvertently opened either from the control room or from the motor control centre resulting in a major release of flammable gas, with subsequent explosion.
   
2. A fire occurred during the removal of a blind. The blind was located downstream of an air actuated valve which was inadvertently opened during blind removal. This released flammable liquid, resulting in a large fire and multiple fatalities.
   

On the 36th anniversary of the Bhopal Gas Disaster

Are we better off in Process Safety Management than what we were when the Bhopal disaster occurred in 1984? I would answer this by saying that those who wanted to improve have certainly done so, with the help of various process safety initiatives by industry. But we continue to hear about many incidents every year that mar the image of the chemical industry. Based on my 41 years of experience (out of which the first 20 years were in operating plants and the next 21 years were in process safety consulting), I think the answer boils down to this basic fact. Some one said " The whole World moves on Vitamin M (Money)". After an incident, there is always a big reaction, but after some time, it becomes business as usual in some companies, and that's when another incident occurs. Can technology prevent incidents? The answer is yes, to a certain degree. But ultimately, it is decisions taken by the humans (and I am not talking about the human sitting in the control room) that cause an incident to occur. In Bhopal gas disaster too, decisions taken far away from the plant had an impact on the plant. 

Mahatma Gandhi had once said "The Earth has enough for everyone's need, but not for everyone's greed". Your views, please....

Nitrogen hose burst due to overpressure

A release of ammonia occurred from a chemical plant when a hose burst following maintenance to an ammonia filter. The release of ammonia was detected by operators due to ammonia alarms and a high flow of ammonia to the plant. The site emergency siren was activated to alert people of the incident and operators isolated the supply of ammonia to the plant. Operators donned personal protective equipment and doused the leak with water in order to gain access to the area to isolate the leak.

Cause

Ammonia filters were used to remove contaminants from the liquid ammonia, prior to it being processed in the plant. An essential step in the maintenance of filters is a nitrogen purge of the system. After purging occurs, the filter is changed, resealed and the nitrogen hose disconnected. The relevant valves are then opened to recommission the system with ammonia. In this instance, the nitrogen hose remained connected to the filter and drain valves were left open allowing the hose to become pressurised with liquid ammonia. While the hose was suitable for the pressures normally experienced under service with nitrogen, the hose was not suitable for the much higher pressures of liquid ammonia and as a result the hose burst in two places.

Source: http://www.dmp.wa.gov.au

Heat exchanger tube leak causes ammonia gasket failure

A mixture of process gases was released to the atmosphere through a failed gasket during the start-up of a chemical plant. Operators had just completed the start-up when they heard a large sound and received alarms from ammonia detectors.The plant was shutdown, however the plume released travelled off-site necessitating the evacuation into refuges of a small number of workers on a neighbouring site. No-one was injured as a result of the release.

An investigation showed that the gasket failed as a result of a hole in a boiler tube which had allowed water to pass from the boiler side into the process side. The temperature generated during start-up caused the pooled water to rapidly boil leading to a surge in pressure which resulted in the failure of the gasket. Non-destructive testing of the boiler tubes showed gouge-type corrosion believed to have been caused by flow distribution problems in the boiler. This resulted in excessive metal temperature, which led to corrosion of the tube.

Source: http://www.dmp.wa.gov.au

Accident due to a temporary connection

The alkylation unit was going into shut down. Two contractors were fixing a copper tube to a T-piece of a drain. During the work they turned the T-piece over 90°. Due to this fact a valve on the T-piece was accidentally opened and an amount of hydrogen fluoride (HF) was released. One of the contractors was very seri-ously injured. His eyes, nose and mouth were burned and he inhaled HF fumes, which caused internal injuries to them. The second person only had small injuries around his mouth.CausesBecause the alkylation unit was shut down, the biggest equip-ment was already emptied and the installation was cleaned with nitrogen. Then it was decided to drain the unit to remove all flu-ids left. The drain consisted of two valves and a blind flange. The blind flange was removed and replaced by a T-piece consisting of a manometer and a small valve. The T-piece was mounted in a horizontal way. A permit was written for two contractors to add a copper tube to the small valve on the T-piece. Because it was not easy to work with the T-piece mounted horizontally they decided to rotate the T-piece. While rotating the piece, the handle of the small valve touched a pipeline which opened the valve and 360ml HF was released. 

Important findings

The T-piece on the drain was a temporary piece only installed for the shutdown. There was no standard in the company to which temporary pieces had to comply. The T-piece used screw thread which made it possible to turn the T-piece. The accident showed that a standard for temporary pieces must be drawn up.In the company it was seen as normal that the manual valves in the line on which the T-piece was fitted had a small internal leak. So in the work permit protective clothing should have been specified for working on this line since they should have antici-pated that HF would build up between the fixed (leaking) valves and the quarter turn valve on the temporary T-piece. A quarter turn valve is easily manipulated accidentally, certainly while doing mechanical work in the immediate vicinity.

Source: European commission

What will go wrong will go wrong!

 On July 14, maintenance works were completed in a soy beans extraction plant. Following the inspection by the plant operator, the start-up of the facility was initiated at 21:30. Steam was admitted to the toaster and to the jackets of hexane inlet pipes to heat-up the toasters and the extractor to the proper operating temperatures.
At about 21:45 the toasters reached their operating temperature and admittance of flakes commenced through the inlet screw conveyor. After that the night shift took over. They had some difficulties controlling the process temperature (dropped), and therefore increased heat supply to the toaster. About the same time, the sound of the safety flap valve lifting was heard, and it released hexane and steam into the extractor building, where the smell of hexane was detected by the operators. The hexane concentration in the extraction building finally reached a level which forced the staff out of the extractor building. A bus driver passing the plant detected the vapours and informed the Traffic Control Centre that “airplane fuel was spilled on the road”. With this information, at their arrival, firefighters took a precautionary approach and parked the fire engine at a safe distance, walking the last hundreds of meters. The plant manager arrived at the scene and discussed with the incident commander how to stop the outflow of hexane vapour, and deciding ultimately to cutoff the power supply to the extraction plant. The manager there after asked the power control unit to turn off two transformers under the load. (There was also one unloaded). Due to inherent risk of possible sparks he rejected stopping the electrically loaded transformers and instead, disconnected the third, unloaded transformer. Approximately 30 seconds later, a sudden fire was observed outside the plant which was followed by a violent explosion. The explosion injured 27 persons, among 7 emergency responders and 20 staff members of the plant. The extraction plant was destroyed by the explosion and was notre-established. The explosion was probably initiated by the attempt to disconnect one of the three supply lines to the extraction plant.

Important findings
• Apparently, the smell of hexane which was detected by the operators was not an abnormal occurrence during the start-up.
• The site also stored large amounts of chlorine and hydrogen in the facility. Therefore, it was urgent that the incident commander and the plant manager work quickly together to prevent the explosion.
• The investigation revealed that no emergency shut-down procedure existed for the extraction plant.

Lessons learned
• Due to the conflict of following orders, the question arises who is in charge to give orders relating to operation of the plant, is it the incident commander or the operator? Who makes final decisions to shut down the electricity? Roles should be identified during normal operation when the operator drafts the internal emergency plan. The fire brigade should have visits to the plant to become familiar with the operation and discuss the emergency procedures with the plant manager and the control room operators.
• Emergency shut-down operations are crucial when operating a plant with the hazards of release of toxic materials or fire/explosion and that these protocols are followed.
• No alarm was activated to inform the public about the hexane release. Information to the public and activating the alarm is one of the most important emergency protocol in case the consequences might affect the nearby population.

Source: European commission

Fire due to welding operation

A fire started at the manhole of an inspection pit for underground pipes of a petroleum storage depot during a welding operation as part of maintenance work on the piping supplying a tank. The underground pipes were feeding eleven tanks in different conditions. At 11:15 a.m., a leak of premium-grade gasoline occurred, followed by a sudden flash. Site technicians attempted to extinguish the ensuing pool fire. The operator activated the internal emergency plan, issued the order to close all motorised valves and called for assistance from petroleum industry partners. At 14.00, emergency responders were still unsuccessful in suffocating the fire with sand. At 15:20 an explosion occurred which was caused by two acetylene cylinders used in the welding operation. Fed by an unknown source, the fire continued to rage for several hours despite firefighting interventions. Eventually, the foot valve on the adjacent gasoline tank was found open by the firefighters. After its closure, the fire receded Intervention efforts were substantial and the toll quite heavy; 15 firemen were burned during the accident: 2 of them were badly hurt, 5 seriously and 8 slightly. Apparently, the firemen suffered burn injuries due to a gust of wind and for the cylinders' explosion. The entry valve of the adjacent tank was left open for an unknown reason.

Important findings
• According to the site director, the piping should have been submerged in water during the onsite works and therefore was omitted from the valve closure checklist and control diagram.

Firefighters encountered myriad difficulties, in particular:
• The fire route to the tank was submerged under a layer of burning hydrocarbons;
• Fire water pipes burst under the weight of vehicles evacuating the zone;
• Lack of information about the source of the fire.

Lessons Learned
• The accident scenario was not included in the site’s risk assessment study. Fires initiated from welding operations are abundant in the literature.  A hazard assessment of tank maintenance operations should examine all possible ignition scenarios (what if?) associated with hot work.
• In order to prevent subsequent fires or explosions to occur, ignition sources, such as the acetylene cylinders should be removed from the area of emergency operation.
• Operators should provide accurate information on location of safety instrumentation to the emergency responders as soon as possible, especially if such devices can contribute to the fire or explosion.

Source: European commission

HCL leak incident

In a sulphur dichloride (SCl2) distillation facility in a chemical plant, a spillage of SCl2 occurred in the retention area for a distillation column in the final stages of distillation, after a leak from a recirculating pump. The SCl2 hydrolysed upon contact with ambient humidity, causing an intensive emission of hydrogen chloride (HCl), which was not detected by the HCl gas detector of the column. But a safety detector installed in the unit gives the alarm at 13:12. The controller placed the unit in safety shut down and then triggered locally the audible and visual alarm while alarm messages appear on the control screens in the control room. The internal emergency plan was activated and the 35 employees were evacuated. The internal fire team, supported by 40 external firefighters, equipped themselves with breathing apparatus and plugged the leak. The cloud of HCl was overcome using 4 lateral fire hose lines. The 120 m³ of water used is collected in a retention pond for reuse in production. The internal emergency plan is terminated at 16:15 pm. The next day a specialized company pumped 800 liters (1,200 kg) of sulfur dichloride from the retention basin into a storage tank. The HCl release remained confined inside the building. 

Source:European commission

Lightning strike in an ethanol tank in distillery

In a distillery, a 5,000-m³ tank containing 1,000 m³ of ethanol at 96% concentration exploded when lightning struck and then ignited. The raised roof fell into the reservoir, which remained intact. However, the tank foot valve cracked upon impact. An emulsifier delivered 2 hours later enabled preventing the fire from spreading to the 1,000-m² retention basin. The blaze was extinguished in 3 hours and the fire-fighters for over 5 hours cooled 3 adjacent 2,500 m³-tanks exposed to the intense heat. During the emergency response, 23,000 litres of emulsifiers stored onsite and a total of 7,000 m³ of water (including cooling water) were used. The loss was valued at 30 million francs (including 2.5 million of alcohol destroyed and 3 million of emulsifier). The extinction water (1,500 m³) collected in the retention basins would be diluted in a lagoon. An outside organization was called to verify the electrical installations of the storage zone. 

An internal response plan drill conducted 2 months earlier, based on a comparable scenario involving one of the tanks involved in the accident, served to facilitate the actual intervention. It had been recommended to install flame arrestors on the vents and the breathing valves on the tanks following a lightning risk evaluation study conducted 18 months prior to the event.

Source: European commission

Hydrogen release incident

 While deplugging a cooling circuit, a block-age suddenly set loose, causing an un-controlled movement of a flexible hose connected to the system. The flexible hose hit several small pipes nearby. Due to the broken pipe work there was a release of hydrogen and butene that lasted about five minutes. Sprinkler systems were activated; no ignition occurred. One employee standing nearby was hit by the flexible hose, causing a severe cut on the upper leg. The estimated production loss was 7 days.

Source: European Commission 

Sulphuric acid tank leak due to foundation collapse

On 4th February 2005 a storage tank containing 16,300 t of 96 % sulphuric acid ruptured. The entire contents of the tank were spilled out into the bund and then overflowed out into the nearby dock. The environmental consequences of the accident were quite significant, the sulphuric acid emission had a serious effect on local flora in the inner and deepest parts of the harbor and harbor entrance area. When the sulphuric acid came into contact with the salt water an exothermic reaction occurred, producing a vapour cloud consisting of hydrogen chloride that drifted northwards along the coastline in the direction of the wind. Fortunately, the wind was blowing towards the sea and away from populated land areas and the cloud diluted very quickly. After the spill approximately 2,000 t of contaminated sulphuric acid remained in the bund. The acid also soaked into about 100,000 square metres of the ground surrounding the spill. 

The cause of this incident was a leak in an underground coolant supply pipe of reinforced concrete installed over fourty years before that resulted in a weakening of the ground under the tank farm. Apparently, water forced its way out of the pipe, eroding the ground near and around the sulphuric acid tank. This erosion damaged the ground under the tank which ultimately failed due to the lack of sup-port of the tank floor. A study of the appearance of the involved part of the coolant supply pipe suggests that the corrosion was a result of an acidic attack on the concrete.

Source: European commission

Pump cavitation causes flange leak

A leakage of a hexane solution from a pump discharge flange during use occurred. The hexane vapor was ignited by a static electricity spark and a fire occurred. Apparently, the flange was loosened by vibrations from the pump, due to cavitation, which was ignored. Routine operations were being carried out on site at the time of the accident. The operation involved the transfer of a hexane solution from an unreacted raw material recovery tank to the washing process through the outlet of the first flange of the pump. The hexane solution leaked, ignited, and burned. The financial costs of recovery and lost production were significant.

Source: European Commission

OSHA CITATIONS FOR A REFINERY INCIDENT

In 2008, a blast at a propylene splitter, injured five people, including one passerby.OSHA fined the facility for the following citations:

- All plant fire protection facilities were not adequately maintained and/or periodically inspected and tested to make sure they were always in satisfactory operating condition and would serve their purpose in time of emergency. Fine: $6,300.

- Process safety information pertaining to the equipment in the process did not include the relief system design and design basis. Employees working for the propylene splitter, alkylation area, catalytic cracker, Cat Light Ends and other units relieved by this flare system were "potentially exposed to equipment failure and subsequent catastrophic release of flammable or toxic materials resulting in toxic exposure, explosion and fire hazards. Proposed penalty: $6,300.

- The process hazard analysis for the propylene splitter unit did not address engineering controls to indicate to board operators the fluid levels in the three propylene splitter towers resulting in a hazard to employees. Proposed penalty: $6,300.

- The company did not develop and implement written operating procedure that involved clear instructions for safely conducting activities. According to information from OSHA, written operating procedures used for start-up of the propylene splitter unit did not provide clear instructions for safely conducting activities, nor did they address operating limits, safety and health considerations, safety systems and their functions. Proposed penalty: $6,300.

- Frequency of inspections and tests of process equipment to maintain its mechanical integrity was not consistent with manufacturer's recommendations and good engineering practices. Also, recommended piping inspection intervals were not followed. Proposed penalty: $6,300.

- The company did not correct deficiencies in equipment outside acceptable limits before further use or in a safe and timely manner. Piping and components at the propylene unit were outside acceptable limits as defined by design codes and standards employed by the company. These design codes and standard limits were exceeded in that component set points and thinning of piping beyond safe and acceptable limits was evident in process equipment. Proposed penalty: $6,300.

- Piping inspection drawings for the reboiler area were not consistent with design specifications. Improper piping thicknesses were indicated and piping retirement thicknesses were not consistent with design specs and recommended good engineering practices. Proposed penalty: $6,300.

- The company did not investigate each incident which result in, or could reasonably have resulted in, a catastrophic release of a highly hazardous chemical in the workplace. Proposed penalty: $1,875.

- The employee alarm system did not provide warning for necessary emergency action as called for in the emergency action plan, or for reaction time for safe escape of employees from the workplace, immediate area or both. Proposed penalty: $6,300.

Source: OSHA.gov

EMERGENCY FIREWATER PUMP COULD NOT BE STARTED FROM THE BRIDGE

 https://www.imca-int.com/alert/1167/near-miss-emergency-fire-pump-not-started-bridge/

FATALITY DUE TO ASPHXYIATION IN ROCK PHOSPHATE

A worker died after getting trapped ina rock phosphate pile. Innocuous  substances also can kill you.

  https://open.alberta.ca/dataset/4dab3567-fbd0-4b5e-9620-fc3d633b377a/resource/fd5d6f93-145d-4225-8cd1-432bbc29c6f8/download/lbr-2016-06-02-carey-report-public.pdf

IDENTIFY THE HUMAN FACTORS THAT LED TO THIS INCIDENT

 https://open.alberta.ca/dataset/7071575b-9876-4c6b-8593-5789adaa84c7/resource/8f1ea562-4676-4fdd-b942-1bce0213206d/download/lbr-fatality-report-f-ohs-102998-22c81.pdf

EXPLOSION IN GAS CONDENSATE TANK

 http://wyomingworkforce.org/_docs/osha/accidents/09-23a-2014.pdf

FATAL ACCIDENT DURING FILTER CHANGE

 http://wyomingworkforce.org/_docs/osha/accidents/09-14-2016.pdf

Do not be fooled by water wells

 http://wyomingworkforce.org/_docs/osha/accidents/06-05-2018.pdf

Fire inside confined space due to halogen light

On Dec. 17, 2013, the worker was spraying a flammable coating on the inside walls of a large steel tank when a fire was ignited by a portable halogen light. The 37-year-old man was rescued but spent three days in the burn unit at Hospital.

Cal/OSHA cited the company for these and other alleged violations:

• Knowingly using an unauthorized electric lamp while the painter was working in an explosive atmosphere.
• Not having a permit to work in a confined space.
• Not having the proper ventilation or protective equipment for such a hazardous space

Source: CAL Osha

Flammable vapours + ignition = Fire

 On September 9, 2005, Employees #1 and #2 were replacing a sump pump on a premium gasoline pump at a BP Gas station. The pump, powered by a 220 volt line, was in a sump that was used to contain fuel residue. After the installation of the new pump, it was tested and failed to operate. While Employee #1 was checking the pump voltage with a volt/ohm meter, he became distracted and allowed a meter lead to short to ground. The resultant spark ignited fuel vapors in the bottom of the sump and caused a flash fire. Employee #1 sustained first-degree burns to his hands and face. Employee #2 was hospitalized first-degree burns to his face. 

Source: osha.gov

Lessons Learned from a Hydrogen Explosion

Lessons Learned from a Hydrogen Explosion: On January 8, 2007, a hydrogen explosion at the Muskingum River Power Plant’s 585-MW coal-fired supercritical Unit 5 caused one fatality, injuries to 10 other people, and significant damage to several buildings. The explosion occurred during a routine delivery of hydrogen when a hydrogen relief device failed, which allowed the contents of the hydrogen tank to escape and be ignited by an unknown source. This article covers the findings of the incident investigation and the actions the plant has taken to prevent a reoccurrence.

Small bore tubing incident

A gas leak occurred at a compressor station when small bore pipework fractured. The incident resulted in a small natural gas release that was successfully resolved without harm, although the licensee identified the potential for the situation to have escalated if it was not for the careful inspection prior to works being undertaken.The small bore pipe that failed was a low point in the drain system located in a pit that was not readily accessible.The root cause was identified as the small bore pipe that failed had not been designed to handle vibration resulting from high gas flows and decreased suction pressures. The small bore pipe’s limited accessibility resulted in it being missed on previous site reviews specifically undertaken to identify potential points of failure due to vibrations.

Source:https://www.dmp.wa.gov.au

HYDROGEN FIRED BOILER EXPLOSION

Bypassing of safety interlocks during start up of boilers have caused many explosions around the World, killing many people. I had investigated one incident where a hydrogen fired boiler was being commissioned and the trips were bypassed as they were causing some problem. The boiler exploded and the operator was killed. Read about another hydrogen fired boiler explosion in this link:

 https://www.dmp.wa.gov.au/Documents/Safety/PGS_SIR_01-2016.pdf

Explosion in molten sulphur tank

Molten sulphur tanks are often not given the importance they deserve. because of the nature of the product, they are dangerous and have to be handled with precautions. This safety alert explains the case of an explosion in an molten sulphur tank. Ensure the learnings are shared. Read the safety alert in this link:

https://epsc.be/epsc_media/Learning+Sheets/2019/19_06+EPSC+Learning+Sheet+_+H2S+explosion-p-660.pdf

Inspection frequencies and OSHA

The most commonly cited equipment for non-compliant inspection frequencies (of any type, not only thickness measurements) have been piping circuits followed by pressure vessels, relief devices, and monitoring alarms. As part of the inspection program, an appropriate inspection frequency must be established for equipment in order to determine whether pipe/vessel thickness is decreasing as expected. API 570 identifies three classes of piping services and recommends a thickness measurement inspection frequency based on the class. For example, Class 1 includes:

• Flammable, 
• Pressurized services that may rapidly vaporize and explode upon release,
• Hydrogen sulfide, 
• Anhydrous hydrogen chloride, 
• Hydrofluoric acid 
• Piping over water of public throughways, and
• Flammable services operating above their auto-ignition temperature.

As discussed in API 570, Class 1 requires a thickness measurement inspection frequency of at least every five years. Classes 2 and 3 require a thickness measurement frequency of at least every 10 years. The inspection interval for specific piping is established by the inspector or piping engineer in accordance with the owner/user’s quality assurance system, but not to exceed the limits set by API 570

Source:Osha.gov

OSHA ASSET INTEGRITY OBSERVATIONS

Examples of equipment cited for violations of the PSM MI requirements that OSHA found during NEP inspections include:

• A broken gate valve caused a level gauge to not work properly, which rendered visual verification of liquid level for the vessel ineffective. This deficiency went uncorrected.
• The installation of an engineered clamp failed to correct a deficient piece of process piping, which was a 90-degree elbow that was outside acceptable limits. The employer continued to use the leaking 90-degree elbow as part of a piping circuit that conveyed waste hydrogen sulfide gas.
• Hydrogen sulfide monitors were not inspected and tested on a regular basis to correct deficiencies in alarms that were outside acceptable limits due to bad sensors, loose wiring, or monitors that needed to be replaced. Work orders were not managed by a tracking system to ensure that deficiencies were fixed in a timely manner. Some work orders marked “fix today” or “ASAP” were not fixed for a week or longer.
• Six relief systems in an alkylation unit were incorrectly sized and were not corrected in a timely manner when the deficiencies were reported. No Management of Change (MOC) was performed to justify the decision to delay replacing the deficient systems.
• Grounding cables were removed from equipment, such as a heat exchanger and pump motors, but were not replaced. 
• Excessive vibration was observed on motors with visible movement of structural steel decking and supports. Also, two 1” pipes and one 4” pipe containing flammable liquid were not adequately supported

Source: Osha.gov

ASSET INTEGRITY ISSUES

Failure to correct equipment deficiencies that are outside acceptable limits39 is one of the leading causes of PSM non-compliance in the petroleum refinery sector. Non-compliance for equipment deficiencies broke down into four major groups:

1. Lack of proper maintenance or repair, 38. 29 CFR 1910.119(j)(1)(i)-(vi)39. 29 CFR 1910.119(j)(5)OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION18
2. Inappropriate installation (such as inappropriate sizing),
3. Missing protective system (such as not including relief devices), and
4. Insufficient structural support.

Equipment most commonly cited for deficiencies were relief devices, followed by piping circuits, pressure vessels, and alarm systems.

Source:Osha.gov

 

Dust collector system explosion

Employee #1 was feeding 400 lb of granular polyalphamethyl styrene (CAS 25014-31-7) through a Mikropal #3 micropulverizer (equipped with a .032 in. screen) into a Mikropal Mikro-Pulsaire dry dust collector. The Mikro-Pulsaire unit has a continuously self-cleaning bag filter located inside the building and had no provision for explosion relief or venting. Apparently a piece of metal between 1 and 2 in. got past the magnet in the micropulverizer, ignited the dust in the system, and caused a fire and explosion that blew open the access door to the dust collector. Employee #1 was standing about 10 ft from the door and sustained second- and third degree-burns on his hands and face. 

Source:Osha.gov

NECESSITY OF REMOTELY OPERATED SHUT OFF VALVES

Thousands of gallons of a highly flammable hazardous chemical spilled for nearly 30 minutes before catching fire at the Intercontinental Terminals Co. tank farm in Deer Park, but the facility did not have a remote emergency shutoff valve nor an alarm to alert workers, according to the U.S. Chemical Safety Board. Source: CSB

Have you studied your system to check the necessity of remotely operated shut off valves?

EXCESS FLOW VALVES MAY NOT WORK PROPERLY

More than 35,000 gallons of propane were released when the discharge hose on an LPG transport truck separated from its hose coupling at the delivery end of the hose, and none of the safety systems on either the truck or the receipt tank worked as intended to stop the release. The DOT determined that emergency systems such as EFVs do not always function properly when a pump is used to unload the protected vessel. If a release occurs downstream of the pump and the EFV activation point is greater than the pump capacity, the pump will function as a regulator limiting the flow to below that required to close the EFV. Courtesy EPA.gov

INCIDENT DUE TO FAILURE OF TWO EFV'S

A methyl mercaptan release occurred when a pipe attached to a fitting on the unloading line of a railroad tank car fractured and separated. Fire damage to cargo transfer hoses on an adjacent tank car also resulted in the release of chlorine gas. Neither of the two EFVs closed to control the release. Three plant employees were killed in the resulting explosion and several employees were injured. Approximately 2,000 local residents were evacuated from their homes for 10 hours. Failure of the EFVs to close contributed to the severity of the incident. The NTSB determined that the facility placed undue reliance on the tank car EFV to close in the event of a leak from the transfer line.Courtesy NTSB.gov

INCIDENT DUE TO FAILURE OF ESV

A chlorine railcar transfer hose ruptured, releasing 48,000 pounds of chlorine. Hundreds of residents were evacuated or sheltered-in-place, and sixty-three local residents sought medical evaluation; three were admitted to the hospital. The chlorine also damaged tree leaves and vegetation around the facility. The CSB determined that an excess flow valve internal to the chlorine railcar did not close, contributing to the severity of the event. As a result of such chlorine releases, the CSB has issued a recommendation to the Department of Transportation (DOT) to expand the scope of DOT regulatory coverage to include chlorine railcar unloading operations and ensure the regulations specifically require remotely operated emergency isolation devices that will quickly isolate a leak in any of the flexible hoses (or piping components) used to unload a chlorine railcar.Courtesy EPA

AUTO IGNITION INCIDENT

An oil spill occurred due to a failure of a block valve to seal properly during maintenance of a pump strainer in the visbreaker unit at a plant in Wickland, Aruba, Dutch Antilles in 2001. The oil auto-ignited and the ensuing fire spread and destroyed the visbreaker and damaged adjacent equipment. Estimated loss was USD 250 million current value. (Marsh)

REMOTE OPERATED ISOLATION VALVES

The Center for Chemical Process Safety has given some good guidelines for remote operated shut off valves. In Many incidents, the consequences are magnified as there was no remote operated shut off valve provided. In many fires and toxic gas releases, the manual isolation valves get engulfed and make it impossible to enter the area to operate the valves. Read the guidelines in this link:

https://www.aiche.org/ccps/remote-isolation-and-shut

Incident of failure of SDV

A recent incident involving the failure of a shut down valve (SDV), and the subsequent failure of two pressure safety valves (PSV), has highlighted issues associated with the selection of SDVs and the need for regular maintenance and testing of SDVs and PSVs.The failure occurred after an electrical supply fault caused an emergency shutdown of a gas processing plant. Upon subsequent start up of the plant and one of the plant’s compressors, an SDV passed on closure allowing the gas pressure to build up in a crossover header between high pressure and low pressure pipework systems. Another compressor was then started further increasing the pressure. Two PSVs in the gas line failed to operate at their set pressure and the pressure continued to rise until a rupture disk relieved to flare.
Courtesy: NOPSA
Read the safety alert in this link

Corrosion in Water Based Fire Sprinkler Systems

Good article!
https://www.facilitiesnet.com/firesafety/article/The-Hidden-Threat-of-Corrosion-in-WaterBased-Fire-Sprinkler-Systems--18984

Fatality due to inadvertent reaction

Employee #1, the basement operator at a powerhouse, was purging the liquid residue from the betene entrainment tank to the #16 boiler. Water and steam inadvertently got into the knockout pot, and materials that react to water, such as, but not limited to, acetic anhydride and diketene were in the tank. A reaction occurred, releasing flammable and hazardous materials into the atmosphere through a safety relief valve. The pressure relief device was only sized for an external fire, not a chemical reaction. As a result, the safety relief valves could not withstand the reaction. The overpressurization caused the steel pot to fail and explode. Employee #1 was killed.
Source:OSHA.GOV

Follow procedures for recomissioning mothballed equipment

https://www.nopsema.gov.au/assets/Safety-alerts/Alert12.pdf

Blog 50 – Be the Process Safety Change You Want to See - News - Process Safety Matters

Blog 50 – Be the Process Safety Change You Want to See - News - Process Safety Matters

VALVE MAGAZINE - mistakes and misconceptions in valve leak testing

This is a good article. Many times, the points mentioned in the article are missed.

https://www.valvemagazine.com/magazine/sections/features/7388-mistakes-and-misconceptions-in-valve-leak-testing.html

Incident due to improperly ventiliated confined space

When I was a shift engineer, I entered a confined space, a pressure vessel, after obtaining necessary work permit. After I entered, I climbed up the internal fixed ladder to inspect a demister located at the top. As I was climbing up, the CO alarm in my personal gas monitor went off and I evacuated the vessel. Investigation determined that  during the purging process after plant shutdown, one part of an isolated pipeline connected with the vessel had not been been purged. When a valve connected to this pipeline was opened by an operator when I was inside, the pocket of trapped gas entered the vessel.

Lesson: Confined space entry can pop up surprises, even after receiving work permit. Ensure your personal gas monitor is working properly before you enter a confined space. It saved my life!

Explosion due to Ammonia vapour

A storage tank for aqueous ammonia solutions was up for maintenance (replacement of the bottom part). After mechanical completion of the replacement work, a trial had been undertaken to fill the tank up, but overpressure was registered and the flange connecting the feeding line to the tank leaked. The problems were reported to the maintenance department, the flange connection was repaired and the pressure relief line checked, the trial to fill the tank was not reported to the shift supervisor. The next day a safe work-permit was issued to the mechanics to disconnect the piping associated with this tank for further repair. The repair work proceeded and during the grinding of a disconnected pipe, a mechanic noticed a whistling sound and hid, together with the other mechanics, behind a concrete tankfarm wall. Soon afterwards the tank exploded. The top of the tank was blown over an adjacent building and the office buildings, and bumped into another office building (approximately 60 m away), which was empty. The explosion is believed to be caused by the ignition of ammonia vapour caused by the repair works. Also the pressure relief line failed to perform as expected.
Lessons
1. Improvement of procedures.
2. Improvement of communication.
3. Improvement of training of personnel.
4. Re-design of vapour relief lines.
Source:COMMUNITY DOCUMENTATION CENTRE ON INDUSTRIAL RISK, MAJOR ACCIDENT REPORTING SYSTEM LESSONS LEARNT FROM ACCIDENTS NOTIFIED, INSTITUTE FOR SYSTEMS ENGINEERING AND INFORMATICS, COMMISSION OF THE EUROPEAN COMMUNITIES JOINT RESEARCH CENTRE, 1991, ISBN 9282622894.

Investigation report of the High Power committe on LG Polymers Visak incident

Things are changing for the good in India. After the Jaipur oil terminal fire was made public, the report of the high power committee of the incident at LG Polymers site at Visakhapatnam,AP has been made public by the Chief minister of A.P
The report is exhaustive and has lot of annexures. One of the issues is the lack of enforcement of facility siting rules. Habitats are permitted to be built near to the plant by the authorities and this makes it a disaster waiting to happen.
I hope the recommendations of the committee are implemented in a time bound manner.
Read the complete report in this link
https://www.ap.gov.in/?page_id=43744

Confined space incident

Three men inside a reactor vessel experienced breathing difficulties. They had inhaled vapour containing 1,1,1-trichloroethane as a result of using a cleaning agent in a poorly ventilated confined space. The three men were taken to hospital for observation and tests. They were discharged on the day following the incident and returned to work fully recovered two days later.The incident resulted from using a hazardous cleaning solvent in an inadequately ventilated confined space. The solvent contained 1,1,1-trichloroethane a harmful substance which should not be inhaled. In addition to the air flow being inadequate to effectively dilute the solvent vapours, the direction of ventilation was wrong. For this heavier than air vapour the air flow should have been from the top downwards.

Lessons
1. No cleaning agents containing solvents should be used in restricted spaces - such as tankers, columns, reactors, large pipelines etc. For the weld testing, water should be used instead of solvent based agents. Investigations should take place as to whether a harmless test process could be used instead of the dye disclosure method.
2. When using a solvent based cleaner, adequate air supply and ventilation should be ensured. If the fumes are heavier than air, they should be extracted from below.
3. If the ventilation is insufficient, independent breathing apparatus must be used.
4. If possible, work should not be carried out on a vessel at the same time as work in the vessel. If this is unavoidable, the persons working inside should be informed of the nature and scope of work being carried out on the outside. We should also check that safety measures governing work in tanks are adequate. A special co-ordinator is required for this.
5. On medical recommendation, various medications should be kept on site, such as Folon A 200 mg injection ampules and Auxilosan measured dose aerosols.
6. All jobs should be carefully planned from beginning to end. Deviations from the plan should require formal authorisation at a high level. Existing work permits should be withdrawn and new permits issued to cover the change in scope. There is a tendency to take less care towards the end of a job as the pressure to recommission plant and equipment increases.
7. The site policy on the use of solvents (and other hazardous chemicals) should be made absolutely clear to everyone who could be affected by their use. Inherent methods of enforcement of the policy should be devised. e.g. if particular solvent based cleaners are not allowed on site the purchasing system should prevent orders for them from being processed.
Source:ICHEME

Have you assessed all the hazards?

Many accidents and fatalities occur during the erection of new equipment in chemical plants. These can include storage tanks. Double wall, double integrity storage tanks are often used for storing cryogenic liquids. In an incident mentioned by osha.gov, An employee was blowing insulation into the annular space of a newly constructed liquefied natural gas tank. He apparently accidentally fell into the space, which was full of perlite. He was engulfed by the perlite and was asphyxiated. Perlite is an insulation material. When a job hazard analysis is carried out, do you consider asphyxiation hazards due to insulation, in double wall tanks?

Are you ensuring the integrity of tank roofs and gauging platforms?

When I was a shift in charge in a naphtha based ammonia plant in the 80's, we used to gauge the level in the tank by climbing up the staircase of the floating roof tank. The tank was provided with a gauging pipe, which we had to open and we used to drop the measuring dip tape with a brass bob attached to the end. We used to apply a paste on the tape, at the approximate level. After we performed the dip, we could observe the exact place where the paste colour had changed and that told us the level. All this while we used to stand on the gauging platform which was mounted on the tank roof. In my 40 years experience since, I have read and heard about quite a few incidents where the person performing the gauging fell into the tank as the roof and gauging platform structure were badly corroded and gave away. In one of the cases in an oil refinery in India, the body got stuck in the heavy oil and they had a tough time removing it.

Another incident reported in OSHA.gov mentions this:

"An employee was taking measurements of Bunker C fuel oil in a tank. He was going to access the tank through a hatch located on its roof. When the employee stepped on the roof, a section of it collapsed because of corrosion. The employee fell inside the tank and died of asphyxiation".

LESSON: Maintain the integrity of your tank gauging platforms and roof, along with the rest of the tank.

Improper isolation incident

Part of a benzene plant was shutdown, as part of the annual shutdown programme. As part of the preparations for maintenance the main process sections were drained, purged and steamed in accordance with the set procedures. Work then began on the stripper column reboiler circuit, including two heat exchangers. The actions required for the preparation of one of the exchangers had been highlighted, and so it was assumed these actions had been completed. Under a Permit to Work the foreman and 4 of his team commenced on unbolting the exchanger end plate and the main channel end flange.
The work was not completed and was carried forward to the next shift. During the work it was noticed that the exchanger surface was still hot. This was assumed to be due to steaming operations in the shell side of the exchanger. The following day under a re-signed Permit to Work, the team continued with unbolting and the exchanger end plate seal was released. Hot condensate spilled out of the bottom section of the exchanger end channel. When the flow ceased the final bolts
were removed from the end plate flange and the end plate cover was rigged ready for lifting down to ground level. Approximately 10 minutes after the end plate was removed, a fitter working adjacent to the area was hit by a large flow of hot condensate, which flowed from the exchanger, impinged on a tube baffle plate and then sprayed over the fitter. He crawled away and colleagues put him under a safety shower until the ambulance arrived. The fitter received scalds to his back and neck. Investigations showed that there had been ineffective isolation of the exchanger system from the live LP plant steam supply. There was also passing valves on the condensate system which contributed to the presence of hot condensate. The highlighted had not in fact been completed and
there had been inadequate physical checking of the isolation work prior to handover for maintenance. The Permit to Work system had not highlighted potential hazards, and due to work overload was not being operated effectively.
Lessons
The following recommendations were made:
1. Key isolation valves should be checked for passing.
2. All work packs were re-checked for proper system isolation before shutdown work recommenced.
3. The organisation and supervision for the shutdown were reviewed and clear requirements for detailed recording and handover of progress between shift
teams were set.
4. A schedule was to be set up for a management review of the progress of the new coordination routine and for general safety auditing of the shutdown
activities on the plant.
5. The lessons learnt from the incident were to be circulated to other plants undergoing shutdown, to identify Best Practice for the future.
6. Generic recommendations from other condensate related incidents were to be reinforced.
Source:IChemE

Pneumatic testing fatality

A worker was killed and another seriously injured during leak testing on a heat exchanger.
The workers were using inert gas when a tube bundle ejected with great force striking them both.
An investigation into the cause of the incident found the following immediate causes:
1. Use of an unsafe work procedure for leak testing of the heat exchanger, no test ring was used and the use of high risk pneumatic test method.
2. Failure to stop test when instructed.
3. Inadequate protection from the potential of tube bundle propelling outwards.
Source:IChemE

Low temperature failure incident

Three nozzles on top of a reactor suffered cracks in the welds during decommissioning of a high-pressure lube oil hydrogenation unit when it inadvertently discharged liquid nitrogen into three reactors. Excessive shrinking occurred, caused by thermal shock.
Damage that occurred to equipment is estimated to be approximately US$55,000 (1999).
Source:IChemE

Coal dust explosion

Six workers were injured and one killed in a coal dust explosion and fire at a power generating plant.
Three injured mechanics and electricians were in critical condition at hospital with third degree burns over more than half of their body.
The accident occurred in a unit of the plant's coal burning plant minutes after workers restarted a coal pulverizer.
The pulveriser had been taken off-line for some maintenance work. The mechanics had finished the maintenance and were testing it. The cause of the explosion is not known.
Source : CNN.COM, U.S. NEWS, AUGUST 16, 1999, (http://www.cnn.com).

Empty drums are dangerous!

A worker welding a pipe onto a 55-gallon drum was seriously injured when oil vapours from the drum ignited causing an explosion. The drum had been used to store waste oil.
Source: csb.gov

Inadequate breathing air capacity kills two

Two workers carrying out sandblasting work inside a 22-by-27 foot boiler were found dead by a third worker at a chemical plant. It is not known what hazardous chemicals were involved as the boiler used water to create steam and did not handle chemicals.
The workers were provided with breathing air due to the nature of the space they were in and because of the sandblasting operation.
An investigation into the cause found a low level of oxygen in the cylinders used.
Source : CNI NEWS, 21 MARCH 2000, (http://www.cnionline.com)

Fire water systems should not be connected to other sources

A fire occurred at a refinery when fire fighting water became contaminated with fuel. An investigation into the incident found a small leak in a closed valve that is meant to separate the fire fighting water used to wash out fuel processing vessels.
Four other valves where meant to serve as backup devices to prevent contaminated water from flowing backward into the fire fighting water. But three were stuck in the open position and the forth one had a broken spring.
The incident occurred when the fire fighting water was sprayed underneath a welding job to quickly extinguish sparks that might ignite any stray vapours from refining units. But the water released a cloud of gas that burst into flames. The worker holding the hose and the welder suffered burns in the fire.
Source:csb.gov

Employee injured by exploding pump

Employee #1, the derrick man on a land oil drilling rig, was operating an auxiliary mud pump during the rigging-up phase of drilling in order to operate the cellar jet. The jet became clogged with rocks and debris, and the pressure relief valve on the pump did not operate. The high-pressure header on the pump came apart, and pieces of it struck employee #1 in the head. The pressure relief valve was found to have been set with a nail instead of a manufacturer's specified shear pin. The nail and valve had both corroded, rendering the valve inoperable. The high-pressure header was found to have suffered erosion around a fitting, which failed under pressure. No routine maintenance or inspection of the pump was conducted by the company.
Source:OSHA.GOV

Worksafe - safe selection and use of flexible hose assemblies

https://www.worksafe.vic.gov.au/safety-alerts/safe-selection-and-use-flexible-hose-assemblies

Incident due to wrong catalyst added

At approximately 4:00 p.m. on February 22, 1998, Employee #3, a chemical operator, added the wrong catalyst for a reaction, causing overpressurization of the vessel. The safety relief valve opened, releasing vapors and liquid that settled to the ground near a roll-up door. Employees #4 through #12, contractors doing pipe fitting work on an adjacent reactor, were exposed to the vapors as they left the area. Employee #1 was exposed during clean-up and Employee #2 was performing housekeeping duties near the roll-up doors. Employees #1 through #12 were transported to the hospital complaining of nausea, dizziness, and chest tightness--all symptoms of acute chemical exposure.
SOURCE:OSHA.GOV

Breathing air hose crimp rings failure

At approximately 14.00 hours on 5th September 1988, an air supply hose on the discharge side of a portable breathing air receiver became detached whilst in use.One individual was carrying out an internal inspection of the Solvent Recovery Column at the time. He was therefore immediately deprived of an air supply.Very prompt action by the compressor attendant, with the assistance of a fireman enabled restoration of the air supply within a few seconds. An emergency call was made to the Fire Station for additional backup, but the individual concerned was able to make his own way out of the column, and suffered no physical effects.On examination the crimping rings attaching the pressure hose to the bayonet connection were found to be loose and showed no signs of ever being compressed.Following the incident, all work involving mobile breathing air systems was stopped. It turned out that all hoses arrived in vacuum sealed packs which were only opened at the work-site. No inspection or testing was therefore performed and no documentation accompanied the hose to indicate what Quality Assurance procedures had been followed.
Lessons
All hoses were examined and certified on site immediately.Some hose lengths were found to have only one crimp-ring applied, rather than the usual two. Initially it was accepted that a second ring should be applied. However, the contractor subsequently discussed this matter with the supplier who advised against this course of action. Clamping is normally carried out whilst the hose is being heat-shrunk onto the fitting. Any attempt to add a second clamp 'cold' might affect the integrity of the original bond.All such hoses were therefore withdrawn from service, and have been replaced by others, which incorporate an improved coupling design.For vessel entry the statutory requirement is for an outside observer who is similarly clothed (and therefore has breathing apparatus (BA) at the ready) whose primary responsibility is to summon assistance in the event of a dangerous situation arising, and to then attempt a rescue. The shutdown arrangements require each party to make its own arrangements for observers. This could therefore involve personnel who had only limited BA training. This situation was revised.
Source:ICHEME

Inadvertent mixing of chemicals causes fatalities

The accident occurred in a plant making dyes and a chromate dip for electroplated products. These products were treated in a series of open-topped tanks located in a sub-basement, known as the zinc-plating room, which contained two parallel rows of tanks separated by a grated walkway. A concrete drainage pit lay beneath the walkway. Ventilation in the zinc-plating room was provided by two ceiling exhaust fans, five windows and the door to the room were closed at the time of the accident.The last tank in the series, where the accident occurred, was used for drying parts after they had been electroplated. The tank measured 1.5 x 1.2 x 1.5 metres. The parts were suspended above the tank, and excess zinc cyanide solution dripped into the tank. Waste zinc cyanide was pumped from the tank once each year.On the day before the accident, an industrial cleaning and hauling company pumped the waste from the tank, leaving a layer of zinc cyanide sludge in the bottom. On the day of the accident the night shift leader began preparations to clean the remaining sludge by spraying 1 or 2 gallons of hydrochloric acid into the drying tank.After investigation it was concluded that the night shift leader unknowingly created hydrogen cyanide, a highly toxic compound, by combining sulphuric acid and zinc cyanide, two commonly used industrial chemicals. Hydrogen cyanide acts to block absorption of oxygen by the lungs and can cause death.After adding the sulphuric acid, the night shift leader, who worked alone and wore no respirator, climbed a ladder and descended into the tank. He did not test or ventilate the tank before entering. After several minutes, co-workers saw him struggling to climb out of the tank.Four other workers attempted to help and were quickly overcome. Two were forced back by the vapours. The other two collapsed, one inside the tank and the other with his head hanging over the edge. Fatality.
Lessons
Chemical safety.Ensure that good chemical safety practices are followed in the workplace:
1. Chemicals must be clearly labelled. Labels must be legible and in English. Warnings to be provided in other languages, as necessary.
2. More emphasis must be placed on dangers that can result from combining chemicals. Workers to be trained to recognise and anticipate hazardous chemical reactions.
3. Materials safety data sheets must provide necessary warnings as well as other important information on chemical hazards
Source :LOSS PREVENTION BULLETIN, 122, 9-10