Compressed Gas: Use and Storage Guidelines

• Store full and empty cylinders separately to avoid confusion. Serious suck-back can occur when an empty cylinder is attached to a pressurized system.
  • See empty cylinder instructions below.
• Select a cool, dry, and well-ventilated area.
  • Cool areas minimize pressure increases that can result from heat or direct sunlight.
  • Dryness deters rust and corrosion.
  • Ventilation is essential in case of leaks.
  • Never store compressed gas cylinders (with the exception of compressed air) in environmental rooms (i.e., refrigerated cold rooms or warm rooms). These rooms are not well ventilated and could pose a serious safety concern should a cylinder fail.
• Arrange storage facilities to permit inventory rotation, using cylinders in order as received from the supplier.
• Do not store cylinders next to doors or in corridors where they could possibly obstruct emergency exit from the building.
• Designate an area to store empty cylinders for return to the supplier. An area on or adjacent to your building's loading dock is suitable.
• Separate oxidizers or other incompatibles (e.g., oxygen) from flammables by at least 25 feet, or by a non-combustible wall.

• Determine which hazard class (I, II, III, or IV) your gas belongs to and ensure it meets all requirements specified for the class.
• Implement these ideal storage practices for class IV compressed gas cylinders:
  • Store cylinders upright and secure them to a substantial, fixed surface with upper and lower restraints made of non-combustible material, preferably chain and Unistrut^®. (See the image at left for an example of properly secured cylinders.)
    Note: During the 1994 Northridge earthquake, gas cylinders that had been double-chained and bolted to a secure surface stayed in place. Single-chain restraints were not as successful. C-clamps did not work at all.
  • Properly label the cylinders and storage area.
  • Cap cylinders when not in use.
  • Store cylinders away from non-compatibles.
  • Store empty cylinders separately from full cylinders.
• Return cylinders to the vendor if they're no longer being used. This removes potential hazards and saves on cylinder rental fees. (Cylinders are typically rented or leased, rather than purchased.)

Compressed gas cylinders restrained with upper and lower chains, secured to a substantial, fixed surface.

Always read the Material Safety Data Sheet and label information before starting work with a new material.

Read Compressed Gas Classification and Requirements Overview for information on hazard classification of particular gases and their specific safety requirements.

• Label both the cylinder and gas line with the name of the gas. Do not depend on color codes.
• Work in a well-ventilated area when using compressed gases.
• Use the correct regulator. Ensure that each gas in use has its own dedicated regulator. Never use adapters.
• Never permit a flame or spark to come in contact with any part of a compressed gas cylinder.
  • Have flashback protectors installed on cylinders of flammable gases, such as oxy-acetylene torch units.
• Use a trap or suitable check valve when discharging gas into a liquid to prevent liquid from getting back into the cylinder or regulator.
• Handle toxic, flammable, and corrosive gases in a fume hood. Use only small cylinders of toxic gases whenever possible. Additional precautions are needed for hazardous gases (classes I, II, and III). Requirements are relaxed for small quantities and short-term usage.
  • See Safety Requirements for Compressed Gas Use for detailed information on requirements and exemptions.
  • See Toxic and Hazardous Gas Classifications to identify the hazardous class of a particular gas.

Caution: Avoid using lecture bottles whenever possible. Lecture bottles use universal threads and valves, and some of them are interchangeable. This increases the risk of accidentally mixing incompatible materials.

In addition to standard storage and operational requirements listed above, employ special precautions for cylinders containing flammable, oxidizing, or corrosive gases (empty or full).

• Flammable gases
  • Storage:
    • Separate from cylinders containing oxidizing gases by a minimum distance of 25 feet or by a noncombustible partition extending not less than 18 inches above and to the sides of the stored material.
    • Store in a ventilated, sprinkled, fire resistant enclosure (e.g., gas cabinet).
      • Note: Fire code piping and connection requirements may apply for your facility. Consult the EH&S Research Assistance Program specialist assigned to your building.
    • Never store flammable gas near ignition or heat sources, or unprotected electrical connections.
    • Keep quantities to a minimum.
      • Caution: There may be circumstances where using a pure flammable gas may pose unacceptable risks. It may be necessary to purchase a reduced concentration mixture (e.g., 1% hydrogen and 99% argon).
    • If you need large volumes (more than 1 large cylinder), contact the EH&S Research Assistance Program specialist assigned to your building.
  • Operations:
    • Use flow restrictors to prevent a sudden large unexpected release.
• Oxidizing gases
  • Storage:
    • Do not permit oil or grease to come in contact with compressed oxidizing gases — explosions may occur!
    • Separate oxidizers from cylinders containing flammable gases by a minimum distance of 25 feet or by a noncombustible partition extending not less than 18 inches above and to the sides of the stored material.
    • Never store oxidizers near flammable solvents, combustible materials, unprotected electrical connections, or ignition or heat sources.
      • Note: Fire code piping requirements may apply in your facility. Consult the EH&S Research Assistance Program specialist assigned to your building.
  • Operations:
    • Diligently clean regulators and tubing used with oxidizing gases to remove oil and other reducing agents.
• Corrosive gases
  • Storage:
    • Never store corrosives longer than 6 months. Cylinders containing corrosives degrade over time.
  • Operations:
    • Inspect cylinder valves periodically for corrosion.
      • If a cylinder or valve is noticeably corroded, contact the gas vendor and follow their instructions.
      • Alert the vendor to any damage that might impair the integrity of the cylinder before the cylinder is returned.
    • Use caution if flow does not immediately start when a valve is opened slightly — there could be a plug in the valve.

In case of cylinder leaks that can't be stopped by tightening the valve gland or packing nut, do the following:

• For hazardous gases:
  • Leave the room, closing the door behind you.
  • Secure the room to prevent entry.
  • Sound the fire alarm.
  • Call for emergency assistance:
    • UCSD Police
      Dial 9-1-1, or (858) 534-4357 from a cell phone. Tell the dispatcher the name of the gas.
    • UCSD Medical Center
      Dial 6-1-1-1, or (619) 543-6222 from a cell phone. Tell the dispatcher the name of the gas.
• For non-hazardous gases:
  • Close the leaking valve. Is it still leaking?
    • Yes – Replace the cylinder cap and notify Environment, Health & Safety (EH&S) at (858) 534-3660.
    • No – Contact STORE for removal at (858) 534-7467.

• Leave the valve protection cap in place until the cylinder has been secured against a wall or bench or placed in a cylinder stand, and is ready for use.
• Use a hand truck or other suitable device to transport cylinders, even for short distances. Secure the cylinder to the hand truck with a chain or strap.
  • Do not roll, drag, or slide containers.
  • Do not lift cylinders by cylinder caps.
• Before returning empty cylinders to the supplier:
  • Close the valve. Leave some positive pressure in the cylinder.
  • Replace any valve outlet and protective caps originally shipped with the cylinder.
  • Mark or label the cylinder "empty" and store it in a designated area for the supplier.
• Important: Move any cylinders that have been left unattended into a secure location as soon as possible.

Helium is a colorless and odorless compressed gas. It is non-toxic and non-flammable. If you use helium to fill balloons for parties or other social events, be aware that careless handling of the cylinders or improper use of helium could cause an accident with serious results.

Follow these guideliness for safely using helium to fill balloons:

• Follow all compressed gas guidelines described on this page. The same hazards and methods for safely transporting, storing, and working with industrial CG cylinders apply to helium cylinders used to fill balloons.
• Always use the proper equipment designed for balloon-filling operations.
  • Order your helium and balloon valve/inflator from STORE for next-day delivery.
  • Note: STORE offers a cylinder cart specifically for helium customers who must move their cylinder (for example, from the side of the ballroom where it's used to inflate balloons to an out-of-the-way location during the festivities).
    • The cylinder cart must be ordered at the same time as the helium.
    • There is no rental fee. However, a deposit is required and will be credited upon return.
• Follow these guidelines for balloon-filling operations:
  • Fill balloons in well-ventilated areas to prevent the risk of asphyxiation.
  • Check all connections for leaks prior to use.
  • Place balloons firmly onto the rubber nozzle and tilt. The further the nozzle is tilted, the higher the pressure that will be released.
  • Make sure the rubber nozzle is not pressing against the inside wall of the balloon neck during inflation. This can blow a hole through the balloon.
  • Close the cylinder at the valve after each use. Helium can leak through the inflator if left on for long periods of time.
  • Never leave the cylinder unattended when it's operational.
  • Never allow anyone to breathe helium from the cylinder. Although helium is not poisonous, it can lead to asphyxiation.
  • Never allow children or unauthorized people to handle balloon-filling equipment.
  • Minimize waste by ensuring gas does not escape when the balloon is being inflated, or when the balloon is removed from the nozzle.
• Transporting the cylinder:
  • Remove the inflator and place the protective cap on before transporting the cylinder to prevent damage.
  • Use a cylinder cart to transport cylinders, even for short distances. Secure the cylinder to the cart so it can't tip, fall over, or bang into another cylinder.
  • Do not roll, drag, or slide cylinders.
  • Do not lift cylinders by cylinder caps.
• Storing the cylinder:
  • Remove the inflator and place the protective cap on the cylinder when storing.
  • Store the cylinder upright and secure it to a substantial, fixed surface with upper and lower restraints made of non-combustible material, preferably chain and Unistrut®. (See the image at left for an example of properly secured cylinders.)
  • Make sure cylinders are not placed where they might form part of an electric circuit.
  • Return empty or unused cylinders promptly to STORE.

Balloon valve/inflator
(valve may vary)

Compressed gas cylinders restrained with upper and lower chains, secured to a substantial, fixed surface.