Presentation on theme: "Near Misses Specialty Gases: Handling precautions and what you need to know [Adapted from Hiyari Hatto (Near Misses) Japan Industrial & Medical Gases Association]"— Presentation transcript:
Near Misses Specialty Gases: Handling precautions and what you need to know [Adapted from Hiyari Hatto (Near Misses) Japan Industrial & Medical Gases Association] Training Package TP – 07/11 Asia Industrial Gases Association 3 HarbourFront Place, #09-04 HarbourFront Tower 2, Singapore Internet:
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Asia Industrial Gases Association 3 Preface Today, a wide variety of Electronic Specialty Gases (ESGs) are used to manufacture semiconductors, liquid crystals, solar cells, etc. and the daily progress of process technology is also leading to the development of new ESGs. The safe use of both conventional and new ESGs requires a good understanding of their properties as well as safe and proper handling techniques. In practice, however, it appears that information on ESGs is often not communicated in accurate, clear or easy-to-understand ways to people who need this information. This package was initially edited by experts of a Specialty Gases Committee of the Japan Industrial and Medical Gases Association (JIMGA), which is made up of manufacturers who produce and supply ESGs in Japan. Case examples of Hiyari-Hatto (Near Misses) are used to illustrate the lessons to be learned.
Asia Industrial Gases Association 4 Move & Transit Accident Scenario (1): A worker moving a cylinder without the valve protection cap resulting in a gas leak.
Asia Industrial Gases Association 5 Move & Transit Accident (1) Possible Causes: The worker moved the cylinder without valve cap on because the protection cap was lost or not available When the cylinder was dropped, the valve was damaged, causing a gas leak. Corrective Actions: When moving gas cylinders, put the valve cap on securely. Learning point: Install protection valve cap before moving a gas cylinder!
Asia Industrial Gases Association 6 Move & Transit Accident Scenario (2): A worker moving a gas cylinder by hand loses control of the cylinder and instinctively tried to grab onto the cylinder. His hand got caught between the cylinder and wall, thus sustaining a hand injury.
Asia Industrial Gases Association 7 Move & Transit Accident (2) Possible Causes: He lost control of the cylinder or lost his balance and could not support the weight securely. He didnt use a cylinder cart. Corrective Actions: Even if the distance is short, when moving a gas cylinder, always use an approved cylinder cart or other transporting equipment and securely chain the cylinder(s) to prevent them from falling off. Learning Point: Use a cylinder cart to move gas cylinders!
Asia Industrial Gases Association 8 Move and transit Accident Scenario (3): While gas cylinders were being transported in a vehicle, some of the cylinders fell off the truck bed onto the road when the truck negotiated a curve. Gas leaked from cylinders.
Asia Industrial Gases Association 9 Move & Transit Accident (3) Possible Causes: The gas cylinders were not properly secured on the truck. In addition, centrifugal force resulting from the trucks excessive speed around the road curve caused the cylinders to move outwards and slid off the vehicle. Corrective Actions: When transporting gas cylinders, strap /tie them securely and drive carefully, especially when taking the curve or corner. Learning Point: Secure gas cylinders properly on transportation vehicles !
Asia Industrial Gases Association 10 Move and Transit Accident Scenario (4): When gas cylinders were being unloaded from the bed of a truck, a cylinder fell and injured a workers leg.
Asia Industrial Gases Association 11 Move & Transit Accident (4) Possible Causes: The gas cylinder was handled roughly. The drop from the vehicle bed to the floor was not controlled. The cylinder fell onto the worker standing on the ground. His foot sustained an injury as he was not wearing safety shoes. Corrective Actions: When handling gas cylinders for loading, unloading or other purposes, handle each cylinder with great care to prevent the cylinder from being subjected to impact, falling over or falling from a height. Always wear leather gloves, safety shoes and other protective equipment when handling cylinders. Learning Point: Do not handle gas cylinders roughly!
Asia Industrial Gases Association 12 Storage Accident Scenario (1) A worker went to remove a silane gas mixture cylinder from the storage room, but took the wrong gas cylinder (however, the mistake was spotted before installing it to the equipment).
Asia Industrial Gases Association 13 Learning Point: Classify gas cylinders by content and store them in assigned storage spaces that can be readily identified! Storage Accident (1) Possible Causes: Gas cylinders for different gases were not stored separately by content in the storage room, and the cylinder was not checked carefully before it was removed. Corrective Actions: Separate cylinders by content and according to full or empty, and store then in assigned storage spaces that can be readily identified. In particular, flammable gases should be isolated from oxidizing gases in storage. Always verify cylinder content before installation!
Asia Industrial Gases Association 14 Storage Accident Scenario (2) A gas leak occurred in the storage room. The toxic gas leak alarm went off, but the emergency decontamination equipment designed to work in conjunction with the alarm did not activate.
Asia Industrial Gases Association 15 Storage Accident (2) Possible Causes: The emergency decontamination equipment (including the emergency exhaust system) did not operate properly because the power supply to the instrument was turned off. Corrective Actions: Check that the gas leak alarm system, emergency decontamination equipment and other devices work on a regular basis, and that preventative maintenance is done on these equipment to ensure that they operate properly at all times. Preventative measures should be taken so that the power supplies for safety equipment will not turn off. An alarm system should be in place to warn of component failure, or failure of power to the system/controls. Learning Point: Ensure that safety equipment used in the storage room is maintained and work properly.
Asia Industrial Gases Association 16 Storage Accident Scenario (3) Some of the cylinders in the storage room fell over in an earthquake and gas leaked from a used cylinder as a result of the impact caused by the fall.
Asia Industrial Gases Association 17 Storage Accident (3) Possible Causes: The cylinders were not properly nested together and/or were not secured by chains or straps. The impact caused by the fall knocked the cylinder valve loose, resulting in a gas leak. Corrective Actions: Properly nest cylinders together and secure both full and empty cylinders stored in the storage room firmly, using double chains or straps to prevent them from falling. Learning Point: When storing gas cylinders, secure them properly to prevent them from falling!
Asia Industrial Gases Association 18 Storage Accident Scenario (4) A used cylinder was found in storage with illegible content label and return instructions.
Asia Industrial Gases Association 19 Possible Causes: Cylinder was not properly entered into a cylinder management system. Label on the cylinder had worn out through extended storage and possibly improper handling. Corrective Actions: Ensure a cylinder management procedure is in place and educate the workforce on importance of compliance to the procedure. Ensure labels remain legible. Return the used cylinder promptly. Learning Point: Promptly return used cylinders ! Storage Accident (4)
Asia Industrial Gases Association 20 Installation & Removal of Gas Cylinders Accident scenario (1): A silane gas mixture cylinder was installed in the gas cylinder cabinet. When the gas entered the vent line after purging, the exhaust port caught fire.
Asia Industrial Gases Association 21 Installation & Removal of Gas Cylinders Accident (1) Possible Causes: Because a cylinder carrying 20% silane was installed by mistake instead of a 3% silane cylinder, the amount of nitrogen dilution provided was insufficient and resulted in a fire. The cylinder was not checked properly before it was installed. Corrective Actions: Before installing a gas cylinder in the gas cylinder cabinet, verify the contents, the gas concentration and whether the cylinder is full or empty by looking at the label or stamp. Learning Point: Before installing a gas cylinder, verify contents and whether its full or empty !
Asia Industrial Gases Association 22 Installation & removal of gas cylinders Accident Scenario (2): During the installation of an oxidizing gas cylinder to a cabinet, the threads of the outlet fitting were checked with bare hands before the cylinder was connected. When the automatic valve was opened to fill the pipe with the actual gas, fire shot out of the outlet fitting and burned the valve outlet fitting.
Asia Industrial Gases Association 23 Installation & removal of cylinders Accident (2) Possible Causes: Because grease had stuck to the outlet fitting when the fitting was touched with bare hands, the oil caught fire due to heat caused by the effect of adiabatic compression and the oxidizing characteristics of gas when the automatic valve was opened. Corrective Actions: Keep clean (grease/oil are strictly prohibited) at all times. Learning Point: Do not handle the cylinder with dirty hands when connecting to a pipe!
Asia Industrial Gases Association 24 Installation & removal of cylinders Accident scenario (3): When the outlet cap was removed from a metal organic gas cylinder returned by a customer, a fire suddenly broke out.
Asia Industrial Gases Association 25 Installation & removal of cylinders Accident (3) Possible Causes: There was some residual gas in the cylinder and the valve had not been completely closed. This caused the gas to come into contact with the atmosphere, resulting in a fire. Corrective Actions: Check the valves to ensure that they are shut off, and that the person is equipped with the specified protective equipment before removing the outlet cap. Educate the customer on proper handling and return procedures and ensure that cylinder valves are properly closed before returning cylinders. Learning Point: Before handling a filled cylinder, always check that the cylinder valve is shut off!
Asia Industrial Gases Association 26 Installation & removal of cylinders Accident scenario (4): When a monosilane cylinder was installed and gas was released, there was a gas leak from the pipe connected to the cylinder and a fire broke out.
Asia Industrial Gases Association 27 Installation & removal of cylinders Accident (4) Possible Causes: The connection pipe was tightened too much during the installation of the cylinder, causing the gasket to deform (the gasket was made of Teflon). Additionally, the leak tightness test was not performed properly. Corrective Actions: When installing a gas cylinder, check the material of the gasket. Examine the gasket, cylinder valve and bolts securing the connection pipe carefully for evidence of nicks, scars, cuts and other surface flaws. Connections should be tightened to within the correct torque ranges. Use the correct pressure when performing the leak tightness test. Learning Point: Install gas cylinders connections with the correct torque and perform leak tightness tests properly!
Asia Industrial Gases Association 28 Installation & removal of cylinders Accident Scenario (5): When a metal organic gas cylinder was removed from the line connection, the metal organic gas leaked from the connection causing a fire.
Asia Industrial Gases Association 29 Installation & removal of cylinders Accident (5) Possible Causes: The metal organic gas remained in the line either because the line was not purged properly or because the cylinder valve was not completely closed. Corrective Actions: Check the purging time and line bake-out before purging. Shut off the cylinder valve completely using a torque wrench. Wear the specified Personal Protective Equipment. Learning Point: When installing or removing gas cylinder, purge cylinder connections completely!
Asia Industrial Gases Association 30 Installation & removal of cylinders Accident Scenario (6): A worker broke the valve handle with spanner trying to open forcibly without knowing the valve was already open.
Asia Industrial Gases Association 31 Installation & removal of cylinders Accident (6) Possible Causes: While the valve was fully opened, a worker misunderstood it to be closed and tried to turn the handle forcibly with a spanner. Corrective Actions: After opening the valve fully, return the handle back to slightly close. Place the open-close tag on the valve at all times. Learning Point: Verify Valve Position!
Asia Industrial Gases Association 32 Installation & removal of cylinders Accident Scenario (7): When disconnecting the cylinder from the manifold piping, the nitrogen gas used to purge the manifold had remained in the manifold piping (indicated on the pressure gauge). Rapid depressurization of nitrogen gas took place.
Asia Industrial Gases Association 33 Possible causes: This is a routine job and the operator was complacent about safety, thinking that nitrogen gas is inert and safe. He had a cursory glance at the pressure gauge but ignored the dial reading and rushed through the step to loosen the connection. He should have taken care to release the pressure slowly before disconnecting the cylinder from the manifold. Corrective Actions: Confirm the reading on the pressure gauge and depressurize the gas in the manifold slowly. Learning Point: Pay attention to the residual pressure in manifold when disconnecting from it ! Installation & removal of cylinders Accident (7)
Asia Industrial Gases Association 34 Installation & removal of cylinders Accident Scenario (8) During a maintenance check on a returned cylinder, the safety valve was tightened due to concerns that the valve was loose, and then the gas leak detector sounded an alarm. The safety valve was tightened further in an attempt to stop the leak, but this only made the leak worse.
Asia Industrial Gases Association 35 Installation & removal of cylinders Accident (8) Possible Causes: When the safety valve was disassembled and examined, it was found that the valve was no longer an airtight seal because the nickel Teflon coated gasket was deformed. Corrective Actions: When the cylinder is filled, do not over tighten any parts sealed with the safety valve, or any thin gasket, because it is possible that the gasket will be deformed and will lose its seal. Learning Point: Do not over-tighten the safety valve of a filled cylinder!
Asia Industrial Gases Association 36 Using gas Accident Scenario (1) The gas leaking from the pressure regulator was ignited when an in- service liquefied flammable gas cylinder was heated up directly in the electric heating jacket.
Asia Industrial Gases Association 37 Using gas Accident (1) Possible Causes: The gas leaked from the pressure regulator that was tightened improperly and the static electricity from the heating jacket was the ignition source. Corrective Actions: Use electrical appliances of appropriate safety classification (e.g. EX-proof) and ban hot work in the area where the flammable gases are used. Do not heat liquefied gas cylinders directly by using a heating jacket. Learning Point: Do not heat a liquefied gas cylinder !
Asia Industrial Gases Association 38 Using gas Accident scenario (2): A worker opened a cylinder to dispense phosphine gas, but as soon as the cylinder valve was opened, the downstream side of the regulator broke, causing a gas leak.
Asia Industrial Gases Association 39 Using gas Accident (2) Possible Causes: The regulator was set to a lower setting, and the cylinder valve was opened so quickly that the downstream pressure rose sharply, breaking the pressure gauge. Corrective Actions: Before opening the cylinder valve, check carefully whether the valve for the gas distribution line is opened or closed, and open the cylinder valve slowly. Learning Point: Open and close the cylinder valve slowly and carefully!
Asia Industrial Gases Association 40 Using gas Accident scenario (3): When the oil trap on a vacuum pump used to exhaust arsine was removed, arsine was released, and the worker was intoxicated by the gas.
Asia Industrial Gases Association 41 Using gas Accident (3) Possible Causes Arsine dissolved in the oil contained in the oil trap of the vacuum pump was released when the oil trap was removed. Corrective Action When maintaining and servicing a vacuum pump used for toxic gas, perform proper tests to detect gas leaks, considering the danger that toxic gas may be produced. Ensure that there is adequate ventilation in the work area, and wear the appropriate respirator or other breathing protection device if necessary. Learning Point: Beware of possible releases of toxic gas while maintaining and servicing vacuum pumps!
Asia Industrial Gases Association 42 Using gas Accident scenario (4): A worker installing a monosilane cylinder into a cylinder cabinet loosened the safety valve by mistake instead of removing the cylinder valve outlet cap, causing a fire.
Asia Industrial Gases Association 43 Using gas Accident (4) Possible Causes: The worker had insufficient knowledge about the cylinder valve. The tool used to install the cylinder valve cap (a spanner) worked on the safety valve as well as the cylinder valve. Corrective Actions: Educate personnel about the construction and functions of the cylinder valve as well as how to operate it. Use dedicated tools for each specific part. Learning Point: Know and understand the construction of cylinder valves
Asia Industrial Gases Association 44 Using gas Accident scenario (5): When the gas leak alarm went off in the clean room, all the personnel rushed for the exit in an attempt to evacuate from the room, causing confusion and chaos.
Asia Industrial Gases Association 45 Using gas Accident (5) Possible Causes: The employees could not respond correctly to the situation because there was no emergency response manual, training or practice drills. Corrective Actions: Create an emergency procedure manual for emergency situations such as when the gas leak alarm is activated. Train and educate employees on emergency and evacuation procedures. Conduct periodic emergency drills in accordance to the manual. Learning Point: Create an emergency response manual and conduct drills on a routine basis!
Asia Industrial Gases Association 46 Using gas Accident scenario (6): Phosphine gas was detected during the maintenance and servicing of an ion implantation equipment, but the maintenance person continued working and developed minor toxic symptoms.
Asia Industrial Gases Association 47 Using gas Accident (6) Possible Causes: Even though toxic gas was detected, the person continued working and ended up inhaling phosphine gas. Corrective Actions: Ensure that respirators and other protective equipment are available at all times in areas where toxic gas is handled. In the event of a gas leak, always wear this equipment before taking further action. Personnel should practise how to put on, wear and take off the respirator on a regular basis and ensure that respirators are available for immediate use. Learning Point: Ensure that protective equipment is available at all times in areas where toxic gas is handled!
Asia Industrial Gases Association 48 Using gas Accident scenario (7): The gas in the cylinder back flowed into another cylinder in service
Asia Industrial Gases Association 49 Using gas Accident (7) Possible Causes: The remaining gas in the cylinder in service was completely consumed and through a wrong operation of the supply system, the gas in another cylinder back flowed into the cylinder due to the differential pressure. Corrective Actions: Closely monitor the remaining gas in the cylinders in service. Ensure operation procedures are implemented to avoid a backflow through a wrong operation and ensure all employees are properly trained and understand these procedures. Learning Point: Closely monitor the remaining quantity of gas contained in the cylinder !
Asia Industrial Gases Association 50 Using gas Accident scenario (8): When a worker opened the valve protection cap in order to reuse the cylinder, the gas leaked out when the valve hand wheel was turned open.
Asia Industrial Gases Association 51 Using gas Accident (8) Possible Causes; When the cylinder was taken out for reuse, the valve outlet cap was not installed in its original position and had been placed on the valve hand wheel. When the valve protection cap was turned open, the valve outlet cap which was wedged between hand wheel and valve protection cap caused the hand wheel to turn and the valve to be opened. Corrective Actions: Install the valve outlet cap without fail after use. Open gradually the valve protection cap. Learning Point: Install the valve outlet cap after removing the cylinder!
Asia Industrial Gases Association 52 Exhaust & Abatement Accident scenario (1): Arsine leaked from the joint area of one of several pipes connected to the inlet port of a piece of arsine gas decontamination equipment.
Asia Industrial Gases Association 53 Exhaust & abatement Accident (1) Possible Causes: A reagent had accumulated at the inlet port of the decontamination equipment, creating resistance in the pipe and causing an increase in pressure. Together with the fact that the pipe was poorly connected, this resulted in a gas leak. Corrective Actions: Perform routine inspections and services of decontamination equipment and other safety equipment, maintain these equipment to ensure that they work properly at all times. Provide separate decontamination equipment for different gases and perform routine leak tightness testing for pipes. Learning Point: Perform routine maintenance and servicing of safety equipment and take care to ensure that the equipment works properly!
Asia Industrial Gases Association 54 Exhaust & Abatement Accident scenario (2): While servicing a dry pump for CVD equipment, the dry decontamination equipment, located downstream, heated up and became discolored (turned black).
Asia Industrial Gases Association 55 Exhaust & Abatement Accident (2) Possible Causes: The pump was serviced without shutting off the inlet valve for the dry decontamination equipment, allowing air and other substances to enter. The arsenic trichloride taken up caused a chemical reaction with the moisture in the air, generating heat. Corrective Actions: When servicing a dry pump or similar part, always shut off the inlet valve to prevent air from flowing into the dry decontamination equipment. Learning Point: Be careful about air flow into the dry decontamination equipment !
Asia Industrial Gases Association 56 Exhaust & Abatement Accident scenario (3): During removal of a pipe and trap located downstream of the process pump for CVD equipment, phosphorus which had accumulated in the pipe and trap caught fire and injured the operator.
Asia Industrial Gases Association 57 Exhaust & Abatement Accident (3) Possible Causes: Air entering from a gap between the shield blank and pipe reacted with phosphorus, causing a fire. Corrective Actions: When removing a pipe, prevent phosphorus from coming into direct contact with the air. Use fire retardant clothing and other personal protective equipment so that personnel are protected from flames if a fire breaks out. Learning Point: Be aware that phosphorus sediment can spontaneously ignite!