Compressed Gas Cylinder Safety

Campaign to Move Cylinders Out of Corridors 2015


In August 2015, the Ad Hoc Safety Committee directed the EHS Office to initiate a campaign to move compressed gas cylinders out of the corridors/hallways. The EHS Coordinators and their teams are asked to:  


  • Present this topic at a rep meeting before you start inspections. Modify the attached slides. (scroll down)
  • Encourage EHS reps to check if there any cylinders in their lab that are no longer needed and can be returned. Also check if all of the cylinders in the corridor belong to their lab. Often they belong to a nearby lab or to a lab that moved.   
  • Educate reps to use the webpage to request that Airgas pick up unneeded cylinder(s) when you don't need to order cylinders. This webpage can also be used to report cylinders that have been relocated.

 


Guidelines for securing cylinders


Restrain compressed gas cylinders securely with a chain, belt or stand at all times to prevent them from falling over. If a cylinder falls, it may shear off its valve, and the escaping high-pressure gas has been known to propel the cylinder like an unguided rocket (view Mythbusters video) It can smash through masonry walls, go long distances and ricochet.


Secure the cylinder above its center of gravity (~2/3 up the cylinder). If the chain or belt is too low or too high, it will not hold the cylinder if it starts to fall. The chain should not be around the neck of the cylinder, since the cylinder could slide under the chain. The chain should not hang below the mid point of a cylinder, since it could topple over the chain.


Protect the cylinder valve with a securely attached valve cap whenever a cylinder is being moved, and at all other times unless a regulator is attached to the cylinder.


Store flammable gases separately from oxygen and combustible materials by at least 20 feet. Highly toxic (health rating 4), pyrophoric gases, nitrous oxide, and other DHS gases should be secured from unauthorized access.


 


Cylinder wall brackets with straps/ belts


Create a service request in Atlas for the Department of Facilities (DOF) to obtain and mount standard wall brackets. These need to be securely attached to hold the weight of the cylinders.  Or you can order wall brackets from VWR or Airgas and then create a service request in Atlas for DOF to mount your brackets.


Wall brackets are strong enough to hold two cylinders strapped together. However, when the strap is taken off to move one cylinder, then both could fall over.


 


Inspect Straps


Follow the steps below.  If necessary, order a replacement from any of the vendors listed on the cylinder strap/holder attachment (scroll down).  Polyester or nylon cylinder straps will resist fraying better than the older straps that are made out of fabric. 


 


Please ask the EHS Reps to inspect Airgas straps in the lab ASAP.  It would be good to check the other brands of cylinder straps if they have time.  These are the steps for the EHS reps or their designee.  


 


If you find a defective Airgas strap or a questionable Airgas strap,


  1. Please send a photo of strap, bldg-room number and the contact person’s information to kblass@mit.edu  Copy your EHS Coordinator.
  2. Replace the Airgas strap with a spare strap that is in good condition or use a chain.
  3. Keep the Airgas strap until you can give it to Katie Blass. Do NOT discard the old strap.

 


Bench type cylinder clamps


These can be obtained from any of the vendors listed on the cylinder strap/bracket attachment (scroll down). The lab bench, which the cylinder is mounted to, must be strong enough for the size and weight of the cylinder.


 


Floor stands for Cylinders (no wall space needed)


We recommend the type that has a bracket, which can be turned over to change sizes depending on the diameter of the cylinder. 2 wing nuts are used to tighten the bracket around the cylinder. Order this from the vendors listed on the cylinder stand options attachment (scroll down). We do NOT recommend the type that has a strap, which must be pulled tight to secure the cylinder because this is not secure enough.  EHS has sample stands that can be borrowed for a few days to check if this option will work. We do NOT recommend stands that are very low and have a very small footprint. These are listed at the end of the cylinder stand options attachment (scroll down).


 


Chains


Some brackets are designed to chain 2-3 cylinders maximum. The bracket needs to be securely attached to the wall to hold the weight of the cylinders: 2 cylinders in parallel or 3 cylinders in a triangle.  Do not use this method to secure more than 3 cylinders because of the hazards described in the first 2 paragraphs on this page. 


Recommended chain link is 1/4 inch in diameter, per Airgas. Chain can be purchased from the Department of Facilities Stockroom (Building E19 1st floor).


 


Restraints to avoid


The following are not strong enough to hold multiple cylinders and EHS recommends replacing these. If many cylinders are secured with one chain/wire/rope, this is very important.


  • Small diameter chain and chain with flat links (less than 1/4 inch in diameter)
  • Straps that are frayed or are starting to fray 
  • Wire
  • Rope

 


Rusty caps + no cylinder wrench = gas leak


If a corroded valve is forced open, it may not close properly afterwards and may leak. You may break the valve causing the entire contents of the cylinder to leak. Contact the gas supplier to replace the cylinder if a valve is difficult to operate.


 


Do not use


  • wrench, hammer, crowbar, etc. to force a valve open or remove a cylinder cap that is stuck (rust, worn threads)
  • WD-40 or other lubricant

 


Safe way to remove a Cylinder Cap


  • Use a cylinder wrench.
  • Tap very gently on either side of cap to loosen the threads.
  • If you still can’t get the cap off and you don’t have a cylinder wrench, ask John Jordan to come to your lab. 
  • If necessary, contact the supplier to replace the cylinder. Airgas Customer Service 866-718-0685  provide the PO# that is on the tag and/or the barcode # on the cylinder (not the tag)

 


To order a cylinder wrench from Airgas or Matheson


Airgas part# SGD90003   $27.52


https://store.mathesongas.com/tw-series-cylinder-wrenches/


Matheson model TW-5 is a specially constructed Cylinder Hand Wheel Wrench that enables easy opening of cylinder valves that have been fitted with a hand wheel. The design is also suitable for removing difficult cylinder caps.


 


Return cylinders that are empty, old, unneeded, abandoned or other unusual situations 


 


Write on the Airgas tag (or tape) EMPTY or Ready for pick up in BIG letters with a marker. Airgas drivers asked us to make it very clear.


Use the webpage to request that Airgas picks up cylinder(s). Airgas coordinates with other vendors to return most types of cylinders.  If a cylinder can not be returned to a vendor, refer to cost of disposal.


  • Contact MIT Cryogenic Lab to pick up their helium (gas) cylinders.
  • If a contractor abandons cylinders, contact the Dept of Facilitiies. 
  • Student Groups can ask SAO to check their purchasing records. 

Resources


Compressed Gas SOP has more detailed information.


Air Liquide Gas Conversion Calculator and Data on 138 Gases


Air Products Safety information for Cryogenic liquids, CO, CO2, Hydrogen, and a few other gases


Airgas cylinder dimensions and comparison chart of the cylinder sizes for several vendors


Mythbusters video

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