Download - The Care and Feeding of Silane
![Page 1: The Care and Feeding of Silane](https://reader036.vdocument.in/reader036/viewer/2022062301/5681572c550346895dc4c65a/html5/thumbnails/1.jpg)
The Care and Feeding of Silane
Art GarciaFM Global
March 23, 2006
![Page 2: The Care and Feeding of Silane](https://reader036.vdocument.in/reader036/viewer/2022062301/5681572c550346895dc4c65a/html5/thumbnails/2.jpg)
This is Silane
![Page 3: The Care and Feeding of Silane](https://reader036.vdocument.in/reader036/viewer/2022062301/5681572c550346895dc4c65a/html5/thumbnails/3.jpg)
This is also ‘Silane’
Fire chief said he was always
making trouble
![Page 4: The Care and Feeding of Silane](https://reader036.vdocument.in/reader036/viewer/2022062301/5681572c550346895dc4c65a/html5/thumbnails/4.jpg)
421
Silane – SiH4
Insert picture of your plant here
![Page 5: The Care and Feeding of Silane](https://reader036.vdocument.in/reader036/viewer/2022062301/5681572c550346895dc4c65a/html5/thumbnails/5.jpg)
Silane Delivery SystemLocation:
Silane should preferably be outside, well separated from buildings. Open cylinder system, without a cabinet is OK. Area needs to be a well ventilated. All bulk systems should be outside.
Outdoor - separate cylinders with steel partitions, preferably away from a wall. Provide deluge sprinkler protection.
Indoor - system should always be in a gas cabinet. Construction to limit damage in an explosion.
![Page 6: The Care and Feeding of Silane](https://reader036.vdocument.in/reader036/viewer/2022062301/5681572c550346895dc4c65a/html5/thumbnails/6.jpg)
Silane Delivery SystemGas Cabinet:
Cabinet should be minimum 12 gauge steel.
Cabinet doors and access windows should be self closing and latching.
Internal sprinkler head.
Class I, Division 2 electrically rated equipment.
Stainless steel welded piping.
![Page 7: The Care and Feeding of Silane](https://reader036.vdocument.in/reader036/viewer/2022062301/5681572c550346895dc4c65a/html5/thumbnails/7.jpg)
Silane Delivery SystemSilane cylinders:
Stainless steel cylinders are preferred.
Aluminum cylinders can be used. Typically these cylinders will be 6061 aluminum alloy.
Do NOT use aluminum cylinders in cabinets which contain two silane cylinders.
If you have two aluminum silane cylinders in a cabinet, install a steel partition between them.
![Page 8: The Care and Feeding of Silane](https://reader036.vdocument.in/reader036/viewer/2022062301/5681572c550346895dc4c65a/html5/thumbnails/8.jpg)
Silane Delivery SystemFlow restriction:
Restrictive flow orifice (RFO) – Installed within the gas cylinder valve body. RFO size should be specified on the cylinder order. RFO size is usually marked or stamped into cylinder.
Excess flow valve or switch (EFV or EFS) – Separate device within the cabinet. Valve will automatically shut off the delivery of gas if the flow exceeds a preset limit.
![Page 9: The Care and Feeding of Silane](https://reader036.vdocument.in/reader036/viewer/2022062301/5681572c550346895dc4c65a/html5/thumbnails/9.jpg)
Silane Delivery SystemAutomatic shutoff:
Automatic cylinder valve (ACV) – ACV is preferred. Valve is integral to the cylinder. Can shut off a leak at the threaded pigtail connection. Must be ordered with the silane cylinder and supported by gas controller.
or
Emergency shutoff valve (ESOV) – Separate valve downstream of the pigtail connection. Can NOT shut off a leak at the pigtail connection. Cylinder has manual valve.
![Page 10: The Care and Feeding of Silane](https://reader036.vdocument.in/reader036/viewer/2022062301/5681572c550346895dc4c65a/html5/thumbnails/10.jpg)
Silane Delivery SystemSilane concentrations:
1.4% and less – Nonflammable
1.4% to ~4.1%* - Flammable
~4.5%* and greater – Metastable mixtures which after a delay can undergo bulk auto-ignition causing significant overpressures
* Dependent on pressure, exit velocity, geometry, and leak size
![Page 11: The Care and Feeding of Silane](https://reader036.vdocument.in/reader036/viewer/2022062301/5681572c550346895dc4c65a/html5/thumbnails/11.jpg)
Silane Delivery SystemSilane holdup:
Limit the holdup of silane to 1% of the net volume of the gas cabinet or enclosure.
Silane volume is the amount of gas contained in the piping between RFOs or between an RFO and the end of the line.
Net volume is the space in the cabinet not occupied by the cylinder or equipment.
![Page 12: The Care and Feeding of Silane](https://reader036.vdocument.in/reader036/viewer/2022062301/5681572c550346895dc4c65a/html5/thumbnails/12.jpg)
RFO
Silane Delivery System
![Page 13: The Care and Feeding of Silane](https://reader036.vdocument.in/reader036/viewer/2022062301/5681572c550346895dc4c65a/html5/thumbnails/13.jpg)
RFO
Silane Delivery System
Piping break – large initial release of silane. This volume release should be less than 1% of the net volume of the cabinet .
![Page 14: The Care and Feeding of Silane](https://reader036.vdocument.in/reader036/viewer/2022062301/5681572c550346895dc4c65a/html5/thumbnails/14.jpg)
RFO
Silane Delivery System
![Page 15: The Care and Feeding of Silane](https://reader036.vdocument.in/reader036/viewer/2022062301/5681572c550346895dc4c65a/html5/thumbnails/15.jpg)
RFOs
Silane Delivery System
Limit amount of silane released due to a line break
![Page 16: The Care and Feeding of Silane](https://reader036.vdocument.in/reader036/viewer/2022062301/5681572c550346895dc4c65a/html5/thumbnails/16.jpg)
Silane Delivery SystemVentilation:
Size the ventilation to limit the maximum concentration of silane to 0.4% by volume.
Base the concentration of silane on the continuous release using the flow rate given by the size of the RFO and the maximum silane pressure.
![Page 17: The Care and Feeding of Silane](https://reader036.vdocument.in/reader036/viewer/2022062301/5681572c550346895dc4c65a/html5/thumbnails/17.jpg)
Silane Delivery SystemVentilation:
Silane flow through RFO vs. various pressures
![Page 18: The Care and Feeding of Silane](https://reader036.vdocument.in/reader036/viewer/2022062301/5681572c550346895dc4c65a/html5/thumbnails/18.jpg)
Silane Delivery SystemVentilation:
800 psi silane cylinder0.010 inch RFO diameter
1.08 cfm flow of silane
1.08 cfm silane X cfm air
X = 270 cfm air
= 0.4 %
![Page 19: The Care and Feeding of Silane](https://reader036.vdocument.in/reader036/viewer/2022062301/5681572c550346895dc4c65a/html5/thumbnails/19.jpg)
Silane Delivery System
![Page 20: The Care and Feeding of Silane](https://reader036.vdocument.in/reader036/viewer/2022062301/5681572c550346895dc4c65a/html5/thumbnails/20.jpg)
Silane Delivery SystemGas monitoring system:
Silane reacting with oxygen in the air
SiH4 + 2O2 SiO2 + 2H2O (excess O2)
As the oxygen is consumed
SiH4 + O2 SiO2 + 2H2
Monitor for silane (hydride), silicon dioxide, hydrogen???
![Page 21: The Care and Feeding of Silane](https://reader036.vdocument.in/reader036/viewer/2022062301/5681572c550346895dc4c65a/html5/thumbnails/21.jpg)
Silane Delivery SystemEmergency shutoff:
Activation of the gas monitoring systemLoss of cabinet ventilationPower failureActivation of the excess flow switchSeismic activity
Manual shutoff – at the cabinet, at the tool, remote shutoff (outside the gas room, control room, etc.)
![Page 22: The Care and Feeding of Silane](https://reader036.vdocument.in/reader036/viewer/2022062301/5681572c550346895dc4c65a/html5/thumbnails/22.jpg)
Silane Delivery SystemMajor Hazards:
Fires
Explosions
How do we stop them?
![Page 23: The Care and Feeding of Silane](https://reader036.vdocument.in/reader036/viewer/2022062301/5681572c550346895dc4c65a/html5/thumbnails/23.jpg)
Silane Delivery SystemHazards:
Outdoor locationsArea without adequate ventilationLack of deluge sprinkler protectionMultiple cylinders exposing each otherMixed cylinder storage
Indoor locationsLack of explosion ventingPoor condition of gas cabinetsUnrated electrical equipment
![Page 24: The Care and Feeding of Silane](https://reader036.vdocument.in/reader036/viewer/2022062301/5681572c550346895dc4c65a/html5/thumbnails/24.jpg)
Silane Delivery SystemHazards:
Over sized RFOs
Excess flow valves or switches with high limits
Automatic shutoffs never tested
Silane systems with large holdups
![Page 25: The Care and Feeding of Silane](https://reader036.vdocument.in/reader036/viewer/2022062301/5681572c550346895dc4c65a/html5/thumbnails/25.jpg)
Silane Delivery SystemHazards:
Lack of adequate ventilationClosed air dampers on exhaust ductsClogged air filters on cabinetsObstructed air inlets
Poor ventilationOpen cabinet windowsOpen cabinet doorsHoles in the top of the gas cabinetUnbalanced air flows between cabinets
![Page 26: The Care and Feeding of Silane](https://reader036.vdocument.in/reader036/viewer/2022062301/5681572c550346895dc4c65a/html5/thumbnails/26.jpg)
Silane Delivery SystemHazards:
Monitoring systems out of calibration
Gas sensing port lines disconnected
Monitoring system not appropriate for silane
Monitoring system not tested
![Page 27: The Care and Feeding of Silane](https://reader036.vdocument.in/reader036/viewer/2022062301/5681572c550346895dc4c65a/html5/thumbnails/27.jpg)
Silane Delivery SystemYou do not want a visit from ‘Silane’
Your town
![Page 28: The Care and Feeding of Silane](https://reader036.vdocument.in/reader036/viewer/2022062301/5681572c550346895dc4c65a/html5/thumbnails/28.jpg)
So hopefully you now know the story about the Care and Feeding of
‘Silane’
Art GarciaFM Global
March 23, 2006