Compressed Gases

Securing straps and/or chains should be 2/3 - 3/4 of the way up on every gas cylinder and tightened at all times so compressed gas tanks do not fall over.

Airgas is the current contracted vendor for UVM.  If you need compressed gases delivered, moved or removed, contact AIrgas in WIlliston, VT at 802-864-0324; they have a driver dedicated to be on UVM's campus daily. Be sure to give them your cell phone number so it can be listed on the delivery form; this way,  the driver can reach you when the compressed gas is delivered. No compressed gas deliveries should be left in a hallway or lab unattended.

Using Compressed Gases Safely

Compressed gases have the potential for creating hazardous working environments.  Types of injuries and accidents that can occur include:

  • Injuries caused by flying objects accelerated by an explosion or pressure release
  • Fires and injuries caused by flammable gas ignition
  • Injuries caused by inhalation of toxic or asphyxiating gases

 

The information below explains the proper storage, handling, use and disposal of compressed gas cylinders.  For more information, contact safety@uvm.edu

Prepare for safe compressed gas cylinder use

Compressed Gas Training

Prepare for a leak or emergency

Label Compressed Gases Properly 

Store and Secure Compressed Gases 

Safety Checklist for Managing Compressed Gases

Transporting Compressed Gas

Compressed Air

Before ordering or using a compressed gas:

Order only what you need.  Compressed gas cylinders come in many sizes. Order the smallest amount available.  

Download and read the Safety Data Sheet from the manufacturer. 

Understand the hazards of the gas you will be using. Gases may be flammable, toxic, corrosive or reactive. 

Provide your cell phone number to the gas company so they can reach you during the actual delivery. Gases must be received by lab personnel; they cannot be left in the hallway or left unattended.

Make sure the gas company will take back the cylinder when you are done. Disposing of compressed gases through UVM' s waste disposal procedure can be very costly to the University.

Choose the proper regulator. Airgas has a lot of information about Regulator Selection, Installation, and Operation on their website.

Compressed Gas Training

The Supervisor is responsible for training everyone in the lab in the inherent hazards of the compressed gases used in the lab. Training should include proper handling, storage and use. If you need additional training, contact Airgas, the locally contracted UVM gas vendor, to train your lab group. 

Check the regulator before attaching it to the cylinder. Be sure you are using the proper regulator for the particular gas that is inside the cylinder. If the regulator connections do not readily fit together, the wrong regulator is being used. Do not force connections to fit, as you may permanently damage the threads.

Emergency Preparedness

Visually inspect compressed gas cylinders during your monthly self-inspection. Check apparatus for proper labels, dents, excessive rust, pitting, bent lines, disconnected lines or other physical damage.

Regularly use "Snoop", soapy water or leak detection equipment to check for leaks in the gas transport system.  If a leak is detected, immediately call the vendor to arrange for the cylinder to be removed. Soap and water can be used to test for leaks with some gases. 

Higher-hazard gases may require redundant levels of engineering controls, such as a leak detection system with an alarm. 

Never use Teflon tape on CGA fittings (straight thread) where the seal is made by a metal-to-metal contact. Use of Teflon tape causes the threads to spread and weaken, increasing the likelihood of leaks.  

Download a compressed gas cylinder safety checklist.

Compressed Gas Labeling

Do not rely on the color of the compressed gas cylinder for identification. Color-coding may be inconsistent from vendor to vendor.

To better understand cylinder markings and identification, Cylinder Identification and Marketings Packaging and Color

Is the compressed gas Full, Part Full or Empty?

Airgas has provided additional perforated hang tags that help to identify if the contents of a cylinder is Full, Part Full or    Empty.  Contact safety@uvm.edu if you need some additional hang tags.    

Storage of Compressed Gases

Brackets designed for compressed gases should be used to store cylinders properly. Propylene straps and/or weight-rated chains can be used and should hold the cylinder 2/3 - 3/4 of the way up. Tighten strap or chain so compressed gases cannot fall over.

Never store compressed gases in exits or egress routes.

Gases should be used and stored only in a well-ventilated area.

Never store gases for longer than one year without use. Always screw on an appropriate gas cap on cylinders that are not in use.

Store compressed gases in an upright position. Never lay them on their side in a cabinet.

Gases should be stored  in the order in which they are received and will be used.

Hazard Communication

Store compressed gases by hazard. This means, gases with the same hazard class should be stored in the same area.  Make sure the labels on tanks can be seen and hang tags are visible showing. 

FLAMMABLE GASES should be kept at least 20 ft. away from combustible materials and/or incompatible gases or substances. Storage areas that have a non-combustible wall at least 5 ft. in height and with a fire resistance rating of at least 30 minutes may be used to segregate gases of different hazard classes in close proximity to each other.

 

TOXIC GASES must be stored in a chemical fume hood or in a properly ventilated gas cabinet.

INERT GASES are compatible with all other gases and may be stored together.

EMPTY TANKS should be stored aways from full tanks and labeled as such.

Securing Gases Properly

Compressed gas cylinders must be secured to a stable object (counter or wall) and secured with a chain or strap above the midpoint, but below the shoulder.  This means the strap should be about 3/4 of the way up on the gas cylinder so it cannot fall over.

Compressed gas cylinders that are less than 18" tall must be secured and stored in an approved stand, cart or wall bracket.

Always screw a cylinder cap on to any compressed gas cylinders that is not in use. 

  1. All threads and mating surfaces of the regulator and hose connections should be wiped clean before the regulator is attached. Clean and dry with a lint-free cloth. Particulates can clog the regulator filter (if so equipped) or cause the regulator to malfunction.

  2. Attach the regulator securely, with the secondary valve closed and with the regulator flow backed off (counterclockwise) before opening the cylinder valve.

  3. Do not permit oil or grease to come in contact with cylinders or their valves, especially cylinders containing an oxidizing gas (e.g oxygen).

  4. Use only a cylinder wrench or other tightly fitting wrench to tighten the regulator nut and tube connections. When working with tubing or tube fittings, where turning a wrench could put torque on weaker system parts, use a second wrench in a suitable location to counter the torque. Never force it.

  5. Teflon tape should only be used on tapered pipe threads where the seal is made at the threads. Do not use teflon tape on cylinder connections or tube fitting connections, all which have metal-to-metal-face seals or gasketed seals. NEVER USE TEFLON TAPE ON AN OXYGEN CYLINDER.

  6. When opening a cylinder valve, open the valve slowly. Point the valve opening away from yourself and other persons. Never use a wrench or hammer to open or close a hand wheel-type cylinder valve. If the valve is frozen and cannot be operated by hand, call and return the cylinder to the gas vendor immediately. Ask for a replacement.

  7. Before a regulator is removed from a cylinder, be sure to close the cylinder valve and release all pressure from the regulator.

  8. Never completely empty a rented gas cylinder. Instead, discontinue use of the cylinder when it has at least 25 psi remaining. Hang a cylinder tag (ES has extra cylinder Full/Empty tags) on it so that others know that it is nearly empty. Verify that the valve is closed. Then, secure with a cylinder cap.

  9. Utilize pressure relief devices; e.g., pressure relief valves and rupture discs where appropriate to protect against the overpressurizing of any element of the compressed gas system that cannot safely withstand full cylinder pressure.

  10. Be sure to use valves, tubing and tube fittings that are designed for the application. If in doubt, contact the manufacturer or distributor.

  11. Where there is any chance for equipment malfunction, inspect the condition of the equipment at appropriate intervals.

Transporting Compressed Gases

Lab personnel may move compressed gas cylinders under the following conditions only:

  • They have received and documented that they have adequate training.
  • The valve is closed, the regulator has been removed and the safety cap is securely in place.
  • An appropriate cart is used.  A cylinder card is required for tanks over 35"' in height, another cart or dolly will work for smaller cylinders.  The cylinder must be secured on the cart.
  • "Hand Rolling" cylinders is not permitted.
  • Lab personnel may not move large (>35" in height) cylinders between floors of a building or outside of a building. 

Contact the Compressed Gas contractor for moving cylinders

  • Between floors,
  • Outside of the building,
  • When you do not have an apropriate cart,
  • When you do not have appropriate safety caps,
  • When you do not have appropriate training.

 

Compressed Air Safety   

Never clean objects, machinery, bench tops, clothing and other things with compressed air. Injuries can be caused by the air jet and by particles thrown into the air and into your eyes or those of a neighbor nearby. 

Please review this pdf  about how to use Compressed Air safely.

The Canadian Center for Occupational Health & Safety has a website that explains the hazards of compressed air as well as its proper use.