Compressed Gas Cylinders

Summary

Personnel who use, handle, or transport compressed gas cylinders should be trained in proper methods to reduce the potential for fires, explosions, physical damage, and/or adverse health effects. 

For departments who wish to establish a new storage area, contact the Division of Campus Planning, Infrastructure, and Facilities for a plan review and any necessary requirements.

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Compressed Gas Cylinder Safety

Types of Compressed Gases and Precautions

Flammable Gases

Flammable gases can/will ignite at a low flashpoint, especially when mixed with air. The quantities of flammable gas that can be stored and used on the floor of a building or within a control area is strictly regulated by the Virginia Statewide Fire Prevention Code (VSFPC), and the allowable quantities decrease for every story above ground level. Each type of flammable gas you have in your area counts towards the maximum you are allowed to have. Examples include: propane, acetylene, hydrogen, methane, and iso-butane.

Precautions

• Do not use near ignition sources (except for protected fuel gases).
• Have a portable fire extinguisher readily available for fire emergencies.
• Do not use a flame to detect leaks, a compatible leak-detection solution must be used.
• Use spark-proof tools when working with, or on, a flammable compressed gas cylinder or system.
• Post a sign stating "No Open Flames" on access doors to areas that use or store flammable gases.
• Manifold systems must be designed and constructed by competent personnel who are thoroughly familiar with the requirements for piping of flammable gases. Consultation with the gas supplier, Environmental Health & Safety Fire Safety, and/or the Division of Campus Planning, Infrastructure, and Facilities before installing manifolds is required. 
• Piping, tubing, and fittings for hydrogen must be approved for hydrogen service. Cast iron pipes and fittings must not be used. Plastic tubing must not be used unless it is approved for hydrogen service.
• Order the smallest sized cylinder you can that will support your research, and do not purchase and store spare cylinders.
• Certain mixtures of gases, such as 5% hydrogen/95% nitrogen are not considered to be flammable because it's mixed with an inert gas.  If you can use these nonflammable gas mixtures for your work, that should be a priority. 
• If you must use large quantities of pure hydrogen gas, consider investing in a hydrogen generator in lieu of using compressed gas cylinders.

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Oxidizing Gases

Oxidizing gases are non-flammable gases, but in the presence of an ignition source and fuel, can support and vigorously accelerate combustion. The quantities of oxydizing gas that can be stored and used on the floor of a building or within a control area is strictly regulated by the VSFPC, and the allowable quantities decrease for every story above ground level. Examples include: oxygen, chlorine, fluorine, and nitrous oxide.

Precautions

• Do not use oil in any apparatus where oxygen will be used!
• Gauges and regulators for oxygen use should be labeled with a warning statement - "Oxygen - Use No Oil."
• Order the smallest sized cylinder you can that will support your research, and do not purchase and store spare cylinders.

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Highly Toxic Gases

Toxic gases are those having a health hazard of 3 or 4, as defined by NFPA 704. The toxic effects of a substance can be either acute or chronic. Acute effects involve short-term, high concentrations that can cause irritation, illness, or death. Chronic effects involve continued exposure to a toxic substance over an extended period of time, resulting in serious and irreversible illness.

The quantities of highly toxic gas that can be stored and used on the floor of a building or within a control area is strictly regulated by the VSFPC, and the allowable quantities decrease for every story above ground level. Examples include: arsine, phosphine, phosgene, and nitric oxide.

Precautions

• All highly toxic gases MUST be stored in a continuously, mechanically ventilated gas cabinet, fume hood, or other enclosure (unless otherwise recommended by the supplier). Please contact EHS for guidance or assistance.
  
• Review the Safety Data Sheet to determine safe use guidelines.
• Order the smallest sized cylinder you can that will support your research, and do not purchase and store spare cylinders. 
• New users should consult with EHS before ordering highly toxic gases.

Medical Gases

Compressed gases intended for inhalation or sedation (human or animal) present additional hazards. Contact Environmental, Health and Safety at 540-231-3600 for additional requirements.

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Cryogenic Gases

Cryogenic liquids and their boil-off vapors rapidly freeze human tissue and cause embrittlement of many common materials, which may crack or fracture under stress. All cryogenic liquids produce large volumes of gas when they vaporize and may create oxygen-deficient conditions.

The quantities of cyrogenic hydrogen or oxygen count against the quantities of flammable or oxidyzing gases respectively that you can have on hand in your area. The quantities that can be stored and used on the floor of a building or within a control area is strictly regulated by the VSFPC, and the allowable quantities decrease for every story above ground level. Examples include: liquid oxygen, hydrogen, nitrogen, argon, helium, and liquid neon.

Precautions

• Transfer operations of cryogenic liquids must be conducted slowly to minimize boiling and splashing. Use appropriate personal protective equipment when transferring cryogenic liquids, including insulated gloves, goggles, and a face shield. 
• In the event of skin contact with a cryogenic liquid, do not rub the skin. Place the affected part in a warm water bath.
• Use only equipment, valves, and containers designed for the intended product, service, pressure, and temperature.
• Inspect the containers for loss of insulating vacuum. If the outside of the jacket on a container is cold or has frost spots, some vacuum has been lost. Empty the contents into another cryogenic container and remove the damaged unit from service. Repairs should only be made by the manufacturer of the container or an authorized service provider.
• Excessive ice build-up (especially beneath the vaporizer or tank) could result in the discharge of excessively cold gas, or structural damage to the cryogenic container and surroundings.
• All cryogenic systems, including piping, must be equipped with pressure relief devices to prevent excessive pressure build-up.
• Do not use open flames or direct intense heat sources to thaw frozen equipment. Hot air, steam, or water can be used to thaw frozen equipment. Do not use water to thaw liquid helium equipment.
• Order the smallest sized cylinder you can that will support your research, and do not purchase and store spare cylinders.

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Inert Gases

Inert gases are non-combustible, non-flammable, and non-reactive to many materials. Examples include: argon, helium, nitrogen, and neon.

Precautions

• Inert gases also displace oxygen and can produce a localized oxygen-deficient atmosphere, and therefore should not be used in enclosed or confined spaces without proper ventilation and/or respiratory protection. 
• Some inert gases are also cryogenic in their liquid state. 
• Inert gases are odorless, colorless, and tasteless - making them even more dangerous because they cannot be detected by a person's senses. 
• Always check for leaks and ensure equipment is in proper working order.

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Corrosive Gases

Corrosive gases react to other materials and produce a chemical reaction that eats into, or gradually wears away the material. Corrosives can be hazardous to all parts of the body, and the eyes and respiratory tract are especially sensitive to exposure. Examples include: hydrogen chloride, chlorine, fluorine, and hydrogen fluoride.

Precautions

• Check equipment and lines frequently for leaks. Metals can become brittle when used in corrosive gas service.
• Use a diaphragm gauge on equipment since steel or bronze gauges can be destroyed by corrosive gases. Check with the supplier for more information.
• Remove regulators after use and flush with dry air or nitrogen.
• Wear appropriate personal protective equipment, such as safety glasses or goggles, face shields, chemical-protective gloves, and aprons.

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Pyrophoric Gases

Pyrophoric gases react so rapidly with air and its moisture that the ensuing oxidation and/or hydrolysis lead to ignition.  Ignition may be instantaneous or delayed.  Spontaneous (instantaneous) ignition or combustion occurs when a substance reaches its ignition temperature without the application of external heat. The hazards are pyrophoric fires, explosions and/or deflagrations, and autoignition of a vapor cloud.  All of these conditions can occur depending on leak location, excess flow control and shutdown of the pyrophoric gas.  Pyrophoric fires are difficult to extinguish.  When pyrophoric fires are extinguished, the gas supply must be shut down promptly by interlocks tied into fire protection and/or detection system, because resulting pyrophoric gas build up has the potential to create vapor cloud detonation.

The quantities of pyrophoric gas that can be stored and used on the floor of a building or within a control area is strictly regulated by the VSFPC, and the allowable quantities decrease for every story above ground level. Examples include silane.

Precautions

• All pyrophoric gases MUST be stored in a continuously, mechanically ventilated gas cabinet, fume hood, or other enclosure (unless otherwise recommended by the supplier). Please contact EHS for guidance or assistance.
  
• Review the Safety Data Sheet to determine safe use guidelines.
• Remote manual shutdown devices for pyrophoric gas flow must be provided outside each gas cabinet or near each gas panel. Automatic shutdown devices for pyrophoric gas flow activated by interlocks tied into fire protection and/or detection must be provided.
• Pyrophoric gas flow, purge, and exhaust systems must have redundant controls that prevent pyrophoric gas from igniting or exploding. These controls include excess flow valves, flow orifices, mass flow controller sizing, process bypass line elimination or control, vacuum-pump inert-gas purging, dilution of process effluent with inert gas and ventilation, controlled combustion of process effluent, ventilation monitoring, and automatic gas shutdown.
• Emergency back-up power must be provided for all electrical controls, alarms and safeguards associated with the storage and process systems for pyrophoric gases.
• All process systems components and equipment must be adequately purged using a dedicated inert gas cylinder.
• New users MUST consult with EHS before ordering pyrophoric gases.
• Pyrphoric gases are not allowed in unsprinklered buildings unless prior approval from EHS has been obtained.
• Certain mixtures of gases, such as 1.5% silane/98.5% nitrogen are not considered to be pyrophoric or flammable, and if you can use these nonflammable gas mixtures for your work, that should be a priority. Please contact EHS for guidance on other gas mixtures.
  
• Order the smallest sized cylinder you can that will support your research, and do not purchase and store spare cylinders.

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Types of Cylinders and Equipment

Cylinder Types

There are two basic types of compressed gas cylinders. Non-refillable cylinders are designed for one-time use and should never be refilled or reused. Refillable cylinders are made of steel or aluminum and are designed for refilling and repeated use. Some cylinders have been in service for over 40 years. Most refillable cylinders have an open interior with walls of 1/4 inch steel and a reinforced neck and bottom. Because commonly used gases are highly pressurized (between 1,500 psig and 2,500 psig), cylinders must be maintained in good condition and protected from accidental damage at all times.

A compressed gas cylinder that has been accidentally knocked over and damaged at the valve can result in extensive property damage and personal injury. Never attempt to stop a damaged cylinder that is spinning in place due to the rapid release of pressurized contents! Leave the area until the contents are dispelled and the cylinder has stopped. 

Cylinder Damage

Inspection

Perform a visual inspection before you accept delivery of the cylinder from the vendor. If the cylinder appears to be damaged or defective, refuse delivery.

Routinely inspect cylinders that are in use for:

• Leaking regulators;
• Physical damage to the cylinder or valves; and/or
• Dented, bulging, gouged, or corroded.

Do not use a cylinder that appears to be faulty. Take it out of service immediately and contact the vendor.

Heat

Effects of heat can cause the cylinder to expand and contract with pressure changes. Cylinders are designed, to some degree, to handle such pressure changes, however, cylinders made of aluminum are affected by heat more than cylinders made of steel and can rupture. Some suppliers use invisible heat strips on the cylinders to identify damage from heat. Strips are invisible under normal temperatures but will turn orange or brown if exposed to more than 120 degrees F. 

Arcing Damage

Arcing damage from welding operations can result in a heat rise sufficient enough to cause a pressure explosion or the pressure relief device to activate. When this occurs on a fuel gas cylinder, such as acetylene, it can cause rapid dissociation within the cylinder resulting in greater destruction and/or injuries. This occurs most frequently on argon, carbon dioxide, helium, and inert mixture cylinders used in heliarc welding when the torch is left dangling on top of the cylinder. For this to happen, the cylinder must be part of the electrical circuit connecting the work to the welding machine. This is highly dangerous even without the arc burn and must not be permitted. Arc burns are easily recognized by a spot, or series of spots, of freshly burned paint, exposing bare metal. When caused by a stick electrode, there can be a deposit of filler metal on the cylinder where the electrode dragged. 

• Never allow the cylinder to become part of an electrical circuit. Do not place the torch or electrode holder on the cylinders for any reason.
• Arc-damaged cylinders must be removed from service and returned to the supplier, who often charges the customer for the cost of the cylinder. 

Dents

Dents can occur from impact or mishandling, which can weaken the walls of the cylinder making it more susceptible to rupture. 

Corrosion

Corrosion from moisture, salt, corrosives, and other materials can corrode cylinders, especially the bottom of the cylinder where stored on the ground. Always store cylinders in a dry location, preferably on a concrete surface.

Cylinder Labeling

All compressed gas containers, cylinders, tanks, and systems must be marked according to ANSI A13.1, CGA C-7, or NFPA 704 depending on whether the compressed gas is stationary, portable, or piped. Contact Fire Safety if unclear about labeling or markings.

Cylinders must contain the following information:

• DOT or ICC (prior to 1968) identification number - ex. DOT3AA2265. This identifies the cylinder material and the service pressure in pounds per square inch.
• Cylinder serial number - ex. SG12152A. The letters "SG" may precede the serial number to indicate a specialty gas cylinder. 
• Original owner of the cylinder - ex. APROINC
• Date of maintenance to indicate the original hydrostatic test (month/year).
• Current owner of the cylinder will appear on the neck ring.
• Retest markings (month, facility, year, rating, stamp). A "+" indicates the cylinder qualified for a 10 percent overfill. A star stamp on the end of the marking indicates the cylinder meets the requirements for a 10-year retest.
• CylinderTrak bar code provides a unique identifier and is used by computer systems to track cylinders through the filling process.
• Cylinder manufacturer's inspection marking, which is unique to the inspector.
• Cylinder tare weight, i.e. the weight of the cylinder plus the valve without product, preceded by the letters "TW."
• Cylinders must also identify their contents, which is typically in the form of a sticker applied near the neck of the cylinder. This is the only acceptable means of identifying non-medical-grade cylinder contents. There are only five medical-grade gases that are permitted to be identified by color. All others are not required to be color-coded, and color codes may vary from one supplier to another.

Regulators, Valves, and Pressure Relief Devices

Regulators

Pressure regulators reduce the high pressures of the stored gas in the cylinder to lower pressures that can be safely used in an operating system. Proper regulator selection is critical for both the safety and effectiveness of operating systems. Regulators are designed to control pressure; they do not measure or control flow unless equipped with devices such as a flow meter specifically designed for such purposes. Regulators can explode. If there is a problem, the regulator will explode frontward and/or backward. The safest place to be standing is always to the side of the regulator's face - preferably with the valve between you and the regulator - to avoid reaching in front of the regulator's face to open the valve. The face of the regulator should always be angled upward (provided a flow meter is not attached), so if there is an explosion, the adjusting screw and debris will fly away from your face.

Regulator connections to cylinder valves must be completely free of dirt, dust, oil, and grease. "Crack" the valve slowly (by opening the valve slightly and then reclosing it) before attaching the regulator in order to blow out dust and debris from the opening. Note: Cylinders containing highly toxic gases should not be "cracked." 

Regulators are attached to the cylinder, or manifold, at the inlet connection. This connection should be tested for leaks with a non-petroleum-based product. Note that many soaps contain petroleum! The connection is marked with a Compressed Gas Association (CGA) number and will be left-hand or right-hand threaded to match the nut or fitting. This prevents a piece of incompatible gas equipment from being connected to the wrong gas supply.

• Right-handed CGA fittings will have a smooth nut surface and have an even number for the second digit, for example, 540 (for oxygen).
• Left-handed CGA fittings will have a notched groove in the surface and have an odd number for the second digit, for example, 350 (for hydrogen). 

Never use damaged or defective equipment. In fact, it's best not to use a regulator that you do not know the history of - it may have been misused or repaired by an unauthorized person. Refer any problems or defects to the manufacturer for recommendations and authorized repair.

Regulator tips:

• Opening a regulator: Stand on the valve side of the cylinder at arm's length so you do not have to reach in front of the regulator's face. Turn your head away from the regulator and open the valve, turning counterclockwise, to blow out dust and debris, and then reclose the valve. 
• Changing a regulator: Close the valve and drain the regulator by backing out the adjusting screw. Disconnect the regulator, making sure not to touch the nut and gland areas. Connect the regulator to the new cylinder.
• Closing a regulator: Turn the valve clockwise to close the valve. Drain the regulator by turning (opening) the adjusting crew to release any gas. Reclose the adjusting screw. 
• Recommendation: To provide easier access and additional safety, purchase wall-mounted regulators which connect to the supply cylinder by hose. This will reduce the handling of the regulator and reduce the likelihood of damage.

Regulators must be removed and valve protection caps secured in place when not "in use" per OSHA. This is defined as within a 24 hour period. 

Valves

If there is a weak point on a compressed gas cylinder, it is the valve stem. If the valve stem should be struck or damaged, the gases under high pressure will escape at high speeds. It's this rapid release that turns the cylinder into an unguided missile. Valves are generally made of brass, but may also be chrome-plated for medical gases, made of aluminum for disposable cylinders, or made of stainless steel for toxic, poisonous, pyrophoric, and corrosive gases. There are three types of valves:

• Pressure seal valve: The sealing mechanism for this two-piece valve stem is provided by a Teflon packing ring that makes contact with a ridge on the upper stem. The force that provides this contact is from a spring located in the handwheel. This spring provides upward force to the upper stem and pulls the stem's sealing ridge into the packing ring. Advantages of this type of valve are that they are extremely reliable, very strong, economical, and user-friendly. Disadvantages include: they are prone to leakage around the stem, the lubricated threads can contaminate high purity applications, and they are inappropriate for corrosives and ultra-high-purity gases.
• Packed valve: This type of valve seals by compressing a large ring of Teflon between the valve body and packing nut, which forces the Teflon to grip the stem. Advantages of this type of valve are that they are economical, and are easily opened and closed. However, they are not as good as diaphragm valves for particle generation and leak integrity, and they open very rapidly.
• Diaphragm valve: This valve uses a two-piece stem separated by non-perforated diaphragms. These diaphragms prevent leakage along the valve stem. The lower part of the stem is encased in a spring, which forces the stem away from the seat when the valve is opened. The upper stem is threaded into the diaphragm retainer nut. When the handwheel is rotated to the closed position, the upper stem pushes on the diaphragms, which deflects downward, forcing the lower stem against the valve seat. Advantages of this type of valve are that they provide superior leak integrity and have no threads or lubricants in the gas stream to generate particles or contaminants. This type of valve is required for most highly toxic or poisonous gases. Disadvantages (of older models) are that they are difficult to close, a wrench or other device may be necessary, there is a potential for malfunction, they are prone to corrosion, and they are prone to open when exposed to vibration and shock if not properly closed and secured. These problems have been eliminated in the majority of the newer models. 

Valve tips:

• Keep valves clean. Do not attempt to open a corroded valve; it may not reseal completely.
• Remember to remove the plastic caps from the opening before attaching a regulator.
• Washers may be required for some gases.
• Cylinders not having fixed handwheels must have keys, handles, or non-adjustable wrenches on the valve stem while they are in service.
• Acetylene valves shall not be opened more than one and a half turns.
• Valves shall be closed before moving a cylinder, when work is completed, and when the cylinder is empty.

Pressure Relief Devices

Compressed gas cylinders shall have a pressure relief device installed to prevent the rupture of a normally pressurized cylinder when inadvertently exposed to fire at high temperatures. There are four basic types of pressure relief devices:

• Rupture disk devices: A flat disk typically made of metal that is designed to burst at a predetermined pressure to permit the release of gas. The pressure rating of the disk is typically stamped onto the face of the device. Examples of gases using this type of device include compressed air, argon, helium, nitrogen, and oxygen. 
• Fusible plug devices: A plug made of fusible metal designed to yield or melt at low temperatures (usually 165 or 212 degrees F). The temperature rating of the fusible metal is stamped onto the face of the device. An example of a gas that uses this type of device is acetylene. 
• Combination rupture disks/fusible plug devices: A rupture disk backed by a fusible plug. In the event of a fire, the fusible metal melts, and cylinder overpressure is relieved by the bursting of the disk. The burst pressure of the disk and the melting point of the plug will be marked with the ratings. Medical grade gas cylinders typically have this type of pressure relief device. 
• Pressure relief valves: A spring-loaded valve opens when the cylinder pressure exceeds the pressure setting of the spring to discharge contents. Once the cylinder pressure decreases to the valve's pressure setting, the valve will normally reseat without leakage.

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Storage and Handling

Location

Compressed gas cylinder storage should be located as follows:

• Away from radiators and other sources of heat.
• In a well-protected, well-ventilated area.
• In a dry area (not on earth/ground).
• Away from salt, corrosives, chemicals, and fumes.
• Out of exits and egress routes.
  • Nonflammable cylinders should not be located closer than 5 feet.
  • Flammable cylinders must not be located within 25 feet from an exit or unprotected opening such as a window.
• Protected from physical damage from striking or falling objects.
• Protected from public tampering (i.e. secured).
• Out of direct sunlight (i.e. less than 120 degrees F).
• Protected from vehicular impact.
• Not stored in public hallways or unprotected areas.
• Bulk storage rooms must be specifically designed for the purposes otherwise quantities will be limited. Contact Fire Safety to obtain approval for any new installation of a cylinder storage area inside or outside campus buildings.

Separation

Separating gas system installations and incompatible gases (flammables and oxidizers) to reduce explosion hazards is one of the easiest safeguards to implement. Separation requirements include:

• Incompatible materials;
• Combustible waste, vegetation, and similar materials;
• Ledges, platforms and elevators;
• Temperature extremes;
• Falling objects;
• Heating;
• Sources of ignition; and
• Exposure to chemicals.

Flammable gases and oxidizers must be separated by a distance of 20 feet, or separated by a physical barrier, such as a concrete block wall or sheet metal at least 5 feet high, having a fire rating of at least one-half hour. Contact Environmental, Health & Safety Fire Safety for different construction options.

Requirements

Compressed gas cylinders must meet the following requirements while in storage or in use:

• All compressed gas containers, cylinders, and tanks must be safeguarded to prevent dislodgement by accident or unauthorized personnel. Physical protection may include guard posts, fenced-in areas, or specifically designed storage areas with approved separation.
• Compressed gas cylinders that are not in use may not be stored in laboratories.
• Cylinders must be secured with a chain or flame retardant strap above the midpoint, but below the shoulder of the cylinder.
  • Cylinders less than 18 inches tall that are difficult to secure with a chain or strap may be secured in approved stands or with wall brackets.
• Store cylinders of the same hazard class in the same area (i.e. poisons/highly toxic, flammables, inerts, corrosives, oxidizers, and cryogenic gases).
• Separate full cylinders from empty cylinders. 
• Cylinders and storage areas must be identified as to contents, for example, a sign indicating "Oxygen/Full" and "Oxygen/Empty" should be displayed.
• Cylinders must be stored in an upright position with the cylinder caps in place.
• Oxidizers and fuel gases must be separated by at least 20 feet, or a noncombustible wall at least 5 feet high with at least a half-hour fire rating.
• Cylinders, especially oxygen, must be kept at least 20 feet from highly combustible or flammable materials.
• Oxidizers and flammables must be kept at least 20 feet from all sources of ignition. 
• Store cylinders so that they are used in the order in which they were received, i.e. first in - first out.
• Do not store cylinders longer than one year without use. Return to the supplier or give it to another laboratory or shop on campus that will use it.
• When a cylinder is not being used, the valve should be closed and the valve protector secured in place. Never store gas cylinders near radiators or other heat sources.

Transportation

In-house transportation

• Regulators must be removed.
• Valves must be closed.
• Valve caps must be on.
• Secure cylinders in a cylinder cart with a chain and move to a new location.
• Use platforms or cradles that keep cylinders upright and secure when lifting with mechanical equipment. Do not lift cylinders by their valve cap! 
• Do not drag or roll cylinders horizontally. 

Short-term vehicle transportation

Some gases are not permitted to be transported in personal vehicles (i.e. vehicles not designed and authorized to transport compressed gas cylinders). There are also maximum quantities of gases that can be transported in certain types of vehicles. Transporting compressed gas cylinders in vehicles that are unsuitable for such purposes, and by personnel who are unauthorized and untrained, can result in serious injury or death. 

The preferred method of transporting cylinders is in the supplier's truck.

If a cylinder must be transported a short distance by an employee, the following requirements must be followed: 

• Cylinders must meet the Department of Transportation's requirements for labeling, marking, and placarding. 
• A suitable vehicle, such as a truck, must be used to transport the cylinder.
• The valve cap must be on the cylinder to protect the valve stem. 
• The cylinder must be secured in an upright position in the back of the truck to prevent cylinder damage, especially the valve stem, during transport. Inspect the cylinder for existing damage prior to attempting transport. 
• The cylinder must be located in the back of the truck to provide adequate ventilation in event of a leak. Direct sunlight or excessive temperatures can result in a release of the cylinder contents. 
• Do not smoke during transport.
• Take a direct route to the new location and do not make any intermediate stops along the way. Avoid heavy traffic routes.
• Remove the cylinder from the vehicle as soon as you have reached your destination. Place it in proper storage. 

Disposal

In most cases, when you purchase a compressed gas, you are only purchasing the contents of the cylinder; not the cylinder itself. Cylinders are considered hazardous waste and are not easily disposed of, and should therefore be returned to the supplier from which they were purchased. 

If the supplier will not take a cylinder back, typically due to age, missing labels, unknown contents, damage, etc., contact Environmental Health & Safety Hazardous Waste for assistance.

Leaking Cylinders

If a leaking cylinder is detected during delivery from the supplier, the cylinder should be rejected and/or returned to the supplier. For other situations, consider the following:

• The nature of the operation.
• The potential location of a release or spill.
• The quantity of material that might be released and the type of contaminant.
• The chemical and physical properties of the gas.
• The hazardous properties of the gas.
• The availability and locations of emergency supplies.
• The department's emergency action plan recommendations.

For cylinders with minor leaks:

• Verify the leak with a flammable gas detector, or an approved leak test solution.
• Try tightening the valve gland or packing nut.
• Place a plastic bag, rubber shroud, or similar device over the top and duct tape it to the cylinder to confine the leaking gas.
• Contact Environmental Health & Safety at 540-231-2982 or call 911.

For cylinders with major leaks:

• Call 911 immediately.
• For fuel gases or highly toxic gases, be sure to turn off any machinery or open flames in the area if it is safe to do so. 
• Evacuate the area and secure the entrances.
• Activate building and area fire alarms on the way out of the area/building.
• Do not re-enter the building until the local fire official gives an "all clear."

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Documents

Guidelines Educational and Research Activities

Contact Information

Robin McCall-Miller, Occupational Safety Program Manager

Phone: 540-231-2341
Email: rmmiller@vt.edu