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