Globe valve spindle failure incident

 Are you maintaining your vent and drain valves?

 Read about a globe valve spindle failure incident in this link:

  https://www.oisd.gov.in/Image/GetSafetyAlertAttachmentByID?safetyAlertID=98

The Dakar Ammonia Accident: Analysis of the Worst Incident at an Anhydrous Ammonia User

 The Dakar ammonia accident, in Senegal on March 24, 1992, is the worst ammonia industrial acci-dent ever. This anhydrous ammonia industrial catastrophe claimed 129 lives and injured another 1,150 workers and citizens.
The accident happened at a peanut oil processing facility where ammonia was used to detoxify the product. Anhydrous ammonia was stored in a portable tank commissioned in 1983 and repaired in 1991 before the incident. The weld repairs made were on cracks detected on the tank's surface. Fre-quent overfilling of the tank ("authorized" to hold 17.7 tonnes) was one of the primary causes noted in the reports. An overpressure inside the tank led to its catastrophic failure releasing 22 tonnes of pressurized ammonia. A heavy white cloud of ammonia aerosol plus vapor spread a significant dis-tance causing fatalities and injuries.
This paper presents an analysis of the incident and the resulting consequences.
Dharmavaram, S., Air Products, Allentown, PA, U.S.A.
Pattabathula, V., S.V.P. Chemical Plant Services, Brisbane, Australia

https://www.uvu.edu/es/docs/paper4a-dakar_accident_final.pdf

Failure analysis of a rubber hose in anhydrous ammonia service

 Interesting analysis of failure of ammonia hose:

Failure analysis of a rubber hose in anhydrous ammonia service
Michael K. Budinski *
National Transportation Safety Board, 490 L’Enfant Plaza East, SW, Washington, DC 20594, United States
 https://core.ac.uk/download/pdf/82491417.pdf

WORKER SERIOUSLY INJURED DUE TO RUPTURE OF AMMONIA HOSE

 https://www.dmp.wa.gov.au/Documents/Safety/MSH_SIR_228.pdf

Anhydrous Ammonia Hose Failure

Anhydrous Ammonia Hose Failure Good case study in ethics.

AMMONIA SHIP UNLOADING INCIDENT

 Summary of incident
On 21 July 2018, a major release of ammonia gas occurred at a Western Australian port.
As part of a standard operation, an ammonia tanker vessel was supplying anhydrous ammonia to a process plant. Following the completion of liquid ammonia unloading, purging of the loading arm and pipework was commenced with ammonia gas supplied by the ship via the onboard storage tank head space.
While the purging operation was underway, an operator inadvertently partially closed a line valve. As the line valve was no longer fully open, a control signal was sent to the plant emergency shut-down (ESD) valve to trip closed.
This resulted in increasing internal pressure and hydraulic hammer in the loading arm, creating significant forces against the loading arm quick connect/disconnect coupler which was not sufficiently tightened for the conditions. These forces caused the loading arm to decouple from the ship’s flange and release ammonia gas. Ammonia continued to flow from the ship manifold until the ship crew manually tripped the ship’s ESD system. The release was estimated to be 1200 kg over 24 seconds.
Five personnel present at the jetty were taken to the hospital for medical examination or assessed by ambulance services. All were released the same day.

 Direct factors
The loading arm quick connect/disconnect coupler disconnected from the ship due to internal pressure.
Contributory factors
The unloading of ammonia was completed without correct engagement of the coupler. This can be attributed to:
- insufficient written instruction provided
The standard operating procedure provided little detail on the correct process for the coupler engagement.
- the control panel provided ambiguous information
A green indicator lamp on the control panel indicated that process to engage the coupler was starting. This indicator can be misconstrued as meaning full engagement has been achieved.
- there was no procedural system to validate the coupler engagement prior to commencing ship unloading
There was no visual check to confirm that the two indicator lines aligned as per the manufacturer’s instructions.
- there was no interlock to prevent unloading unless the coupler was fully engaged.
The process relied on procedural controls.
There was full reliance on the coupler installation with no secondary back-up system.
At the flange connection, there was only one control measure to ensure continuity of attachment. As the coupler is an electric-hydraulic system, various faults in the system could result in a loss of connection.
Hazard identifications and risk assessments did not adequately identify all reasonable control measures for the interface between the ship and the plant.
Manual intervention by a third party was required to stop the flow of ammonia from the ship. There was no automated system to shut the supply of ammonia from the ship in the event of a plant emergency at the time of the incident.
Actions required
To ensure similar incidents do not happen, the following actions are recommended for all operations involving quick connect/disconnect couplers.
Ensure the quick connect/disconnect coupler is correctly engaged by:
- confirming the standard operating procedure provides adequate written instructions
- attending periodic refresher training from the vendor
- implementing checklist hold points to confirm critical systems are in place prior to unloading
- installing transducers on the coupler and interlock with the safety system.
Install a locking mechanism on the coupler to ensure it cannot be inadvertently decoupled.
Review and revise the hazard identification and risk assessments to ensure all reasonable control measures are in place at the interface with third parties. For ship transfers:
- install a ship to shore safety shutdown system to automatically close the ship manifold valve in the event of a plant ESD.
Revise competency and refresher training for all personnel working with couplers.

SOURCE: https://www.dmp.wa.gov.au/Documents/Dangerous-Goods/DGS_SIR_0119.pdf

Safety Alert - Failure to detect dangerous gas/vapour due to incorrect specification of sample tube

 https://www.hse.gov.uk/safetybulletins/failure-to-detect-dangerous-gas.htm?utm_source=govdelivery&utm_medium=email&utm_campaign=dangerous-gas-safety-alert&utm_term=main&utm_content=alert-bulletin-1609

Anhydrous Ammonia Hose Failure

Anhydrous Ammonia Hose Failure Good case study for learning ethical behaviour

LINE BREAKING INCIDENT

 On November 28, 1999, a blockage occurred somewhere in the recycle waste line on the second level. This line brings crude Teal with excess aluminum to T-103, which feeds back to the reactors. During the night shift they were able to blow the line from T-105 to the control valve, which left the blockage within about 20 feet of T-103. The morning of November 29, 1999, Employee #1, the outside operator, tried to blow out the plug through a detail (bleeder) just above T-103 with 150 pounds of nitrogen. 

The nitrogen pressure went around the control valve via a by-pass to the slop tank. He closed the valves back toward the slop tank. Then he opened the valve into T-103 to try and blow nitrogen into the tank, but it was still plugged somewhere, which was about 1 to 2 feet of line. At this point they were going to have to perform a line break and separate the line above the valve on T-103.  The line breaking permit was obtained. Employee #1 relieved the nitrogen pressure back to the slop tank, but the slop usually had 3 to 10 psig on it. He ensured that the valves were closed, locked and tagged. 

Then the maintenance crew came to perform the line break. The crew consisted of four employees, which all wore a hard hat with attached face shield, safety shoes, safety glasses, PVC gloves, nomex, and aluminized suits. Employee #1 stayed in the area, but over at the guard rail. The guard rail was just under 10 feet and was about 9.5 feet from the line break. He wore the same PPE except the face shield and aluminized suit. The maintenance crew proceeded to break the flange. One bolt was out and the other three were loose. The shift supervisor was standing on the ground level talking with the Employee #1. Employee #1 told him the flange started to drip. It started to spray lightly and then quickly just gave way into a stream. The stream hit Employee #2 in the face, because he was kneeling as he was working. Employee #1 saw the flames. As he was being burned by the fire, he jumped over the guard rail and fell approximately 12 feet to the ground. Employee #1 sustained a fractured ankle and compressed L1 vertebrate, and was killed. The flash fire lasted about 10 seconds according to the shift supervisor. Employee #2 was hospitalized for his burns. Three other employees were burned during the accident but didn't require hospitalization. 

Source:OSHA.GOV

CONFINED SPACE ENTRY INCIDENTS - USCG

 This incident again reminds us of the dangers of confined space entry.

"Last Fall a foreign flagged containership during a coastwise voyage reported upon leaving port that
the vessel’s second engineer was missing. Despite an extensive search by the vessel’s crew and
officers, the individual was presumed to have gone ashore and missed the sailing. Upon arrival at
the following port the individual was found deceased behind an access door to the main propulsion
engine’s scavenging air receiver:

Read how the fatality occurred in this link:

https://www.dco.uscg.mil/Portals/9/DCO%20Documents/5p/CG-5PC/INV/Alerts/0204.pdf

 

Safety Alert High Velocity Vent Valves, Vacuum Valves, P/V Valves USCG Alert

"A recent marine casualty resulted in significant damage to tank structures, piping and components of
a combination chemical / oil product carrier. Vessel-to-vessel loading operations were taking place at
anchorage and one tank became over-pressurized. Subsequently, three cargo tanks and three
ballast tanks on the ship suffered catastrophic structural failures that allowed hazardous cargo to
migrate throughout those areas. This incident caused the vessel to list and created a very dangerous
explosion hazard requiring costly and time-consuming lightering and repair operations. Additionally, it
presented a hazard to the port and persons involved.
The investigation is nearly complete and investigators have identified several causal factors, one being the failure of the high velocity vent valve which did not open and prevent over pressurization of the tank while it was being filled".

Read the safety alert to understand why the high velocity vent valve failed to operate, in this link:

 https://www.dco.uscg.mil/Portals/9/DCO%20Documents/5p/CG-5PC/INV/Alerts/0411.pdf

IT’S THE SEEMINGLY MINOR ITEMS that sometimes can create a catastrophe. USCG Safety alert

"This is a reminder to owner operators that sometimes it is the most seemingly minor thing such as a
mechanical part or electrical component that can lead to a catastrophe. For example, a nearly 20 year
old bulker was leaving port when its main engine throttle failed. In this case the vessel was able to
drop anchor without incident. The failure occurred because a small drive belt that connected the console throttle lever components to an electrical potentiometer failed. Movement of the throttle causes the
potentiometer to move and creates a variable signal to other controls which manage engine
speed. When the belt failed the control from the engine room console was lost"

Read this safety alert in detail with additional incidents mentioned in this link

https://www.dco.uscg.mil/Portals/9/DCO%20Documents/5p/CG-5PC/INV/Alerts/ll0114.pdf

Overeating Can Create Dangerous Gas! (Especially with Anaerobic Bacteria) USCG safety alert

 This safety alert is very much applicable to us in the CPI. Anaerobic bacteria reside in ETP's.

This safety alert shares important information related to a unique, not very well known and potentially
deadly hazard that recently developed on a vessel involving the formation of dangerous levels of
Hydrogen Sulfide (H2S)1 gas within a waste oil tank. This was determined to be due to the use of
biodegradable cleaners and the chemical reactions and resultant H2S byproduct involved in breaking
down oils in an anaerobic (low oxygen) environment like that found in a full slop tank. In this case,
vessel officers had detected significant H2S concentrations (>200 PPM) in the vessel’s engine room
bilge holding tank.The cleaner provided micro-nutrients to the waste water thus causing the bacteria to thrive resulting in increased rates of H2S production.

Read the safety alert with detailed incidents in this link https://www.dco.uscg.mil/Portals/9/DCO%20Documents/5p/CG-5PC/INV/Alerts/0818.pdf?ver=2018-06-08-143912-267

Danger! Improper Bonding During Gas Freeing Can Have Explosive Results! USCG Safety Alert

"During gas freeing operations, cargo tank manway and butterworth openings are opened and the flammable vapors within the cargo tank are then removed using mechanical air moving equipment. As outside air is introduced into the cargo tank, the vapor/air mixture within the tank, and near the tank openings, will fall into the flammable range. During this time, if the air moving equipment used to gas free the cargo tank is not the proper type, is not properly maintained, or is not properly electrically bonded and secured to the vessel’s structure, static electricity generated by the air moving equipment can discharge as an electric arc and ignite the flammable vapor/air mixture".

Read the full safety alert with photos in this link https://www.dco.uscg.mil/Portals/9/DCO%20Documents/5p/CG-5PC/INV/Alerts/0120.pdf?ver=2020-01-30-101338-710

TANK SAMPLING DANGERS / H 2 S Threshold Limit Change USCG Safety alert

"Prior to using portable gas monitoring equipment, personnel should familiarize themselves with
ISGOTT Section 11.8 and safe work practices for conducting or witnessing these tests. ISGOTT
recommends when sampling tanks personnel should stand perpendicular to the wind to avoid being
downwind or upwind and creating eddies".

Read the safety alert in this link  https://www.dco.uscg.mil/Portals/9/DCO%20Documents/5p/CG-5PC/INV/Alerts/0214.pdf

 

Electrical Issues Spark Major Concern – Addressing Hazardous Area Electrical Installations Knowledge Gaps

"The purpose of this Safety Alert is to emphasize the importance of properly installed and maintained
listed or certified safe electrical equipment in hazardous areas in order to reduce the risk of fire or
explosion onboard vessels. The Coast Guard has seen a number of instances where there was a lack
of knowledge in the marine industry as it relates to the installation, training,
maintenance and inspection of these certified systems"

Read the alert in this link https://www.dco.uscg.mil/Portals/9/DCO%20Documents/5p/CG-5PC/INV/Alerts/USCGSA_0520.pdf?ver=2020-07-06-132441-980

Failure of pipeline emergency shut-down valve - HSE UK

 This alert is issued following the failure of a spring return pipeline emergency shut down valve (ESDV). The failure left the primary platform isolation device inoperable with the valve failed in the open position. Other ESDVs have been examined and have found to be at risk of failing in this manner. Spring return valves other than ESDVs are equally vulnerable.

Read the full report in https://www.hse.gov.uk/safetybulletins/pipelinevalve.htm

Chloride induced stress corrosion cracking of stainless steel thermowells: Potential for ingress of atmospheric moisture HSE UK

"This safety notice describes a specific degradation mechanism found inside stainless steel thermowells operating where the external atmosphere contains halides, as is typical in coastal locations or near to cooling towers. Thermowells can 'breathe' during normal operation as vessels heat up and cool down, drawing in the external atmosphere through non gas tight fittings. If the atmosphere contains halides this can leave any stainless steel susceptible to Chloride Stress Corrosion Cracking (CISCC). The HSL Research Report 902 (Reference 1) covers the susceptibility of stainless steel to CISCC in some detail and links to other research papers and published documents".

Read the full safety alert in this link  https://www.hse.gov.uk/safetybulletins/thermowell-corrosion.htm

Catastrophic rupture of dead-leg pipe-work -HSE UK

"A recent failure on a UK refinery involved an 8" diameter vertical relief line, approximately 5m in length, which catastrophically failed during normal operation part way along its length, releasing approximately 75 tonnes of extremely flammable material at elevated temperature and pressure. Connected to an insulated process header and vessels, the failure involved complete separation of the relief line (which was not insulated).

Subsequent examination of the line revealed excessive internal thinning which was very local to the failure point, but relatively normal wall thickness elsewhere along its length. The inspection regime included regular thickness testing at four locations, but not at the area local to the failure. Notably, an adjacent relief line was also found to have very similar localised and severe internal corrosion, which had also gone undetected".

Read the full incident in this link  https://www.hse.gov.uk/safetybulletins/catastrophic-rupture-dead-leg-pipe-work.htm

Failure of a road tanker pressure/vacuum relief valve

 

"This safety alert is aimed at haulage contractors, users of tank containers and road tankers, companies servicing pressure/ vacuum relief valves and authorised inspection bodies contracted to verify the functioning of these valves.

Tank containers and road tankers used for flammable, corrosive and toxic liquids and gases will normally have a valve fitted to prevent damage to the tank from changes in the internal pressure. Haulage containers used for less hazardous liquids and gases may also have a valve.

Following a road incident in April 2020, investigations by Cleveland Police and HSE found evidence that a pressure/vacuum relief valve, originally manufactured by Fort Vale Engineering Ltd, had been modified by a third party. The valve cap had a nut welded to the top, most likely to allow it to be serviced without the use of a special tool to remove the valve cap. The unauthorised modification prevented the valve’s safe operation"

Read the full report here https://www.hse.gov.uk/safetybulletins/failure-road-tanker-pressure.htm