Gas cylinder

For the mechanical devices used to impart a force from a pressurized gas, see pneumatic cylinder. For the large structures used to store town gas, see gas holder.

Industrial compressed gas cylinders used for oxy-fuel welding and cutting of steel.

A gas cylinder or tank is a pressure vessel used to store gases at above atmospheric pressure. High-pressure gas cylinders are also called bottles.

Nomenclature differences

In the United States, "bottled gas" typically refers to liquefied petroleum gas. "Bottled gas" is sometimes used in medical supply, especially for portable oxygen tanks. Packaged industrial gases are frequently called "cylinder gas", though "bottled gas" is sometimes used.

The United Kingdom and other parts of Europe more commonly refer to "bottled gas" when discussing any usage whether industrial, medical or liquefied petroleum. However, in contrast, what the United States calls liquefied petroleum gas is known generically in the United Kingdom as "LPG"; and it may be ordered by using one of several trade names, or specifically as butane or propane depending on the required heat output.

Materials

For a detailed discussion about the materials for gas cylinders see pressure vessel.

Design codes and application standards along with the cost of materials dictated the choice of steel with no welds for most gas cylinders, treated to be anti corrosive. There have been some newly developed lightweight gas cylinders from composite materials. Due to the very high tensile strength of carbon fiber, these vessels can be very light, but are much more difficult to manufacture.^[1]

Regulations and cylinder testing

The transportation of high-pressure cylinders is regulated by many governments throughout the world. Various levels of testing are generally required by the governing authority for the country in which it is to be transported. In the United States, this authority is the United States Department of Transportation (DOT). Similarly in the UK, the European transport regulations (ADR) are implemented by the Department for Transport (DfT). For Canada, this authority is Transport Canada (TC). Cylinders may have additional requirements placed on design and or performance from independent testing agencies such as Underwriter's Laboratory (UL). Each manufacturer of high-pressure cylinders is required to have an independent quality agent that will inspect the product for quality and safety.

Within the UK the "competent authority" — the DfT — implements the regulations and appointment of authorised cylinder testers is conducted by UKAS, who make recommendations to the VCA for approval of individual bodies.

There are a variety of tests that may be performed on various cylinders. Some of the most common types of tests are hydrostatic test, burst test, tensile strength, Charpy impact test and pressure cycling.

During the manufacturing process, vital information is usually stamped or permanently marked on the cylinder. This information usually includes the type of cylinder, the working or service pressure, the serial number, date of manufacture, the manufacture's registered code and sometimes the test pressure. Other information may also be stamped depending on the regulation requirements.

High-pressure cylinders that are used multiple times — as most are — can be hydrostatically or ultrasonically tested and visually examined every few years.^[2] In the United States, hydrostatic/ultrasonic testing is required either every five years or every ten years, depending on cylinder and its service. Helium gas cylinders have the highest pressures possible when full, around 1000 atmospheres.

Valve connections

A gas regulator attached to a nitrogen cylinder. From right — main valve, cylinder pressure gauge, low-pressure valve, outlet pressure gauge, 3-way outlet terminated by needle valves.

When gases are supplied in gas cylinders, the cylinders have a stop angle valve at the end on top. Often, gas cylinders are somewhat long and narrow and may stand upright on a flattened bottom at one end with the valve at the top. During storage, transportation, and handling when the gas is not in use, a cap may be screwed over the protruding valve to protect it from damage or breaking off in case the cylinder were to fall over. Instead of a cap, cylinders commonly have a protective collar or neck ring around the service valve assembly.

When the gas in the cylinder is ready to be used, the cap is taken off and a pressure-regulating assembly is attached to the stop valve. This attachment typically has a pressure regulator with upstream (inlet) and downstream (outlet) pressure gauges and a further downstream needle valve and outlet connection. For gases that remain gaseous under ambient storage conditions, the upstream pressure gauge can be used to estimate how much gas is left in the cylinder according to pressure. For gases that are liquid under storage, e.g., propane, the outlet pressure is dependent on the vapor pressure of the gas, and does not fall until the cylinder is nearly exhausted. The regulator could be adjusted to control the flow of gas out of the cylinder according to pressure shown by the downstream gauge. The outlet connection is attached to whatever needs the gas supply, such as a balloon for example.

The valves on industrial, medical and diving cylinders are usually of different size and type, as are the valves for different products, making it more difficult to mistakenly misuse a gas. Some fittings use a right-hand thread, while others use a left-hand thread; left-hand thread fittings are usually identifiable by notches or grooves cut into them.

In the United States, valve connections are sometimes referred to as "CGA connections," since the Compressed Gas Association (CGA) publishes guidelines on what connections to use for what products, e.g., In the United States, an argon cylinder will have a CGA 580 connection on the valve.

High purity gases will sometimes use CGA-DISS ("Diameter Index Safety System") connections.

In the EU, DIN connections are more common than in the United States.

Safety and standards

Improper/dangerous handling: Gas cylinders should be chained to a wall for safety, but cylinders are best chained individually to the wall to allow one to be selected without unsecuring the rest. Cylinders should never be stored in direct sunlight or places where high temperatures may occur.

Because the contents are under pressure and are sometimes hazardous, there are special safety regulations for handling bottled gases. These include chaining bottles to prevent falling and breaking, proper ventilation to prevent injury or death in case of leaks and signage to indicate the potential hazards. Installing and replacing gas cylinders should be done by trained personnel. If a compressed gas cylinder tips over, causing the valve block to be sheared off, the rapid release of high-pressure gas may cause the cylinder to be violently accelerated, potentially causing property damage, injury, or death. To prevent this, cylinders are normally secured to a fixed object or transport cart with a strap or chain.

In a fire, the pressure in a gas cylinder rises in direct proportion to its temperature. If the internal pressure exceeds the mechanical limitations of the cylinder and there are no means to safely vent the pressurized gas to the atmosphere, the vessel will fail mechanically. If the vessel contents are ignitable, this event may result in a "fireball".^[3] If the cylinder's contents are liquid, but become a gas at ambient conditions, this is commonly referred to as a Boiling Liquid Expanding Vapour Explosion (BLEVE).

Medical gas cylinders in the UK and other countries have a seal of Wood's metal between the valve block and the cylinder body. This seal melts at a comparatively low temperature (70 °C) and allows the contents of the cylinder to escape in a controlled fashion, lessening the risk of explosion.

More common pressure relief devices are of a simple burst disc type. In these, a small burst disc is installed in the back of the valve. A burst disc is a small metal gasket engineered to rupture at a pre-determined pressure. Some burst discs are backed with a low-melting-point metal, so that the valve must be exposed to excessive heat before the burst disc can rupture.

The Compressed Gas Association sells a number of booklets and pamphlets on safe handling and use of bottled gases.

Cylinders should be properly labeled and securely stored. Substances that may react with each other, e.g., oxidizers and flammable materials, should not be stored in close proximity.

International and US standards

ISO 11439: Gas cylinders — High-pressure cylinders for the on-board storage of natural gas as a fuel for automotive vehicles ^[4]
ISO 15500-5: Road vehicles — Compressed natural gas (CNG) fuel system components — Part 5: Manual cylinder valve ^[5]^[6]
US DOT 3/4/8???: e-CFR (Electronic Code of Federal Regulations) Title 49, part 178, Subpart C - Specification for Cylinders ^[7]
US DOT Aluminum Tank Alloy 6351-T6 amendment for SCUBA, SCBA, Oxygen Service - Visual Eddy inspection ^[8]
AS 2896-2011:Medical gas systems—Installation and testing of non-flammable medical gas pipeline systems pipeline systems (Australian Standards).

Color coding

Gas cylinders are often color-coded, but the codes are not standard across different jurisdictions, and sometimes are not regulated. Cylinder color can not safely be used for positive product identification; cylinders have labels to identify the gas they contain and the label alone should be used for positive identification.

Common cylinder sizes

In scuba diving, the United States measures cylinder volume by the amount of free air that can be compressed into the cylinder; Europe and most of the rest of the world measure the cylinder volume as the internal volume of the cylinder: e.g. United States 19 cubic feet = European 3 liter at 180 bar.

The below are example cylinder sizes and do not constitute an industry standard.

Cyl. size	Diameter × height (inches), includes 5.5 inches for valve and cap	Nominal tare weight (lb), includes 4.5 lb for valve and cap	Water capacity (lb)	Internal volume @ 70 °F (21 °C), 1 atm liters (cubic feet)	U.S. DOT Specs
2HP	9 × 51	187		43.3 (1.53)	3AA3500
K	9.25 × 60	135	110	49.9 (1.76)	3AA2400
A	9 × 51	115	96	43.8 (1.55)	3AA2015
B	8.5 × 31	60	37.9	17.2 (0.61)	3AA2015
C	6 × 24	27	15.2	6.88 (0.24)	3AA2015
D	4 × 18	12	4.9	2.24 (0.08)	3AA2015
AL	8 × 53	52	64.8	29.5 (1.04)	3AL2015
BL	7.25 × 39	33	34.6	15.7 (0.55)	3AL2216
CL	6.9 × 21	19	13	5.9 (0.21)	3AL2216
XL	14.5 × 50	75	238	108 (3.83)	4BA240
SSB	8 × 37	95	41.6	18.9 (0.67)	3A1800
10S	4 × 31	21	8.3	3.8 (0.13)	3A1800
LB	2 × 15	4	1	0.44 (0.016)	3E1800
XF	12 × 46	180		60.9 (2.15)	8AL
XG	15 × 56	149	278	126.3 (4.46)	4AA480
XM	10 × 49	90	120	54.3 (1.92)	3A480
XP	10 × 55	55	124	55.7 (1.98)	4BA300
QT	3 × 14 (includes 4.5 inches for valve)	2.5 (includes 1.5 lb for valve)	2.0	0.900 (0.0318)	4B-240ET
LP5	12.25 × 18.25	18.5	47.7	21.68 (0.76)	4BW240
Medical E	4 × 26 (excludes valve and cap)	14 (excludes valve and cap)		4.5 (0.16)	3AA2015

Common cylinder valves

With the exception of lecture bottles, gas cylinders are often outfitted with non interchangeable fittings. These are specified by the Compressed Gas Association (CGA) in the United States and by the British Standards Institution in the UK. Incompatible connectors help to prevent accidental mis-connections of gasses (e.g. a hydrogen cylinder does not fit an oxygen supply line which would end in catastrophic failure). In the British Standard system, this is effected by fitting flammable gas cylinders with left-hand threaded valves (most commonly brass, BS4, valves for non corrosive cylinder contents or stainless steel, BS15, valves for corrosive contents). Non flammable gas cylinders are fitted with right-hand threaded valves (most commonly brass, BS3, valves for non corrosive components or stainless steel, BS14, valves for corrosive components).^[9]

Gas type	CGA Valve Outlet (USA)	BS Valve Outlet (UK)^[9]
Acetylene	510	2,4
Air, Breathing	346	3
Air, Industrial	590	3
Argon	580,718,680(3500 psi),677(6000 psi)	3
Butane	510	4
Carbon dioxide	320,716	8
Carbon monoxide	350,724	4
Chlorine	660,728	6
Helium	580,718,680(3500psi)	3
Hydrogen	350,724,695(3500psi)	4
Methane	350	4
Neon	580,718	3
Nitrogen	580,718,680(3500 psi),677(6000 psi)	3
Nitrous oxide	726,712	13
Oxygen	540,714	3
Oxygen mixtures (>23.5%)	296	Other guides apply
Propane	510	4
Xenon	580,718	3

References

↑ See Composite overwrapped pressure vessel for details
↑ Henderson, N. C.; Berry, W. E.; Eiber, R. J.; Frink, D. W. (1970). "Investigation of scuba cylinder corrosion, Phase 1". National Underwater Accident Data Center Technical Report Number 1 (University of Rhode Island). Retrieved 2016-01-11.
↑ "Incident Insights - Trust But Verify". Divers Alert Network.
↑ "ISO 11439:2000 - Gas cylinders -- High pressure cylinders for the on-board storage of natural gas as a fuel for automotive vehicles".
↑ "ISO 15500-5:2001 - Road vehicles -- Compressed natural gas (CNG) fuel system components -- Part 5: Manual cylinder valve".
↑ "CNG Cylinder Valve ISO 15500 -".
↑ US DOT e-CFR (Electronic Code of Federal Regulations) Title 49, part 178, Subpart C - Specification for Cylinders - eg DOT 3AL = seamless aluminum
↑ Federal Register / Vol. 71, No. 167 / Tuesday, August 29, 2006 / Rules and Regulations Title 49 CFR Parts 173 and 180 Visual Edddy
1 2 BS 341-3:2002, British Standards Institution, 389 Chiswick High Road, London, W4 4AL

External links

NASA - Safety Standards for Oxygen and Oxygen Handling

Packaging

General topics	Active packaging Child-resistant packaging Disposable food packaging Food packaging Luxury packaging Modified atmosphere/modified humidity packaging Package pilferage Package testing Packaging engineering Pharmaceutical packaging Reusable packaging Shelf life Sustainable packaging Tamper-evident Tamper resistance Wrap rage

Containers	Aerosol spray Aluminium bottle Aluminum can Ampoule Antistatic bag Bag-in-box Bags and flexible containers Barrel Beer bottle Biodegradable bag Blister pack Boil-in-Bag Bottle Box Bulk box Carboy Carton Chub Clamshell Corrugated box design Crate Drum Envelope Flexible intermediate bulk container Foam food container Folding carton Growler Insulated shipping container Intermediate bulk container Jar Jerrycan Jug Juicebox Keg Matryoshka doll Multi-pack Oyster pail Packet (container) Padded mailer Pail Paper bag Paper sack Plastic bag Plastic bottle Popcorn bag Retort pouch Sachet Security bag Self-heating can Self-heating food packaging Shaker-style pantry box Shipping container Skin pack Spray bottle Tin can Tube Unit load Vial Wooden box

Materials and components	Adhesive Aluminium foil Bioplastic Biodegradable plastic BoPET Bubble wrap Bung Cellophane Closure Coated paper Coating Corrugated fiberboard Corrugated plastic Cushioning Desiccant Double seam Foam peanut Glass Hot-melt adhesive Kraft paper Label Linear low-density polyethylene Liquid packaging board Low-density polyethylene Metallised film Modified atmosphere Molded pulp Nonwoven fabric Overwrap Oxygen scavenger Packaging gas Pallet Paper Paper pallet Paperboard Plastic film Plastic pallet Plastic wrap Polyester Polyethylene Polypropylene Pressure-sensitive tape Screw cap Screw cap (wine) Security printing Security seal Shock detector Shock and vibration data logger Shrink wrap Slip sheet Staple (fastener) Strapping Stretch wrap Susceptor Tear tape Temperature data logger Time temperature indicator Tinplate Velostat

Processes	Aseptic processing Authentication Automatic identification and data capture Blow fill seal Blow molding Calendering Canning Coating Containerization Curtain Coating Die cutting Electronic article surveillance Extrusion Extrusion coating Graphic design HACCP Hermetic seal Induction sealing Injection molding Laminating Laser cutting Molding Papermaking Plastic welding Plastics extrusion Printing Quality assurance Radio-frequency identification Roll slitting Shearing (manufacturing) Thermoforming Track and trace Vacuum forming Ultrasonic welding Vacuum packaging Verification and validation

Machinery	Barcode printer Barcode reader Bottling line Calender Can seamer Cartoning machine Case sealer Check weigher Conveyor system Extended core stretch wrapper Filler Heat gun Heat sealer Industrial robot Injection molding machine Label printer applicator Lineshaft roller conveyor Logistics automation Material handling equipment Mechanical brake stretch wrapper Multihead weigher Orbital stretch wrapping Palletizer Rotary wheel blow molding systems Shrink tunnel Staple gun Tape dispenser Turntable stretch wrapper Vertical form fill sealing machine

Environment, post-use	Biodegradation Environmental engineering Glass recycling Industrial ecology Life-cycle assessment Litter Paper recycling Plastic recycling Recycling Reusable packaging Reverse logistics Source reduction Sustainable packaging Waste management

Anesthesia (outline)

Types	General Spinal Epidural Conduction anesthesia Local Topical Intercostal nerve block Sedation / Twilight anesthesia Dental (Inferior alveolar nerve) Neuroleptanalgesic anesthesia

Techniques	Airway management Anesthesia provision in the US Arterial catheter Bronchoscopy Capnography Dogliotti's principle Drug-induced amnesia Intraoperative neurophysiological monitoring Nerve block Penthrox inhaler Tracheal intubation

Scientific Principles	Blood–gas partition coefficient Concentration effect Fink effect Minimum alveolar concentration Second gas effect

Measurements	ASA physical status classification system Baricity Bispectral index Direct Fick method Entropy monitoring Fick principle Goldman index Guedel's classification Mallampati score Neuromuscular monitoring Thyromental distance

Instruments	Anaesthetic machine Anesthesia cart Boyle's machine Gas cylinder Laryngeal mask airway Laryngeal tube Medical monitor Odom's indicator Relative analgesia machine Vaporiser Double-lumen endotracheal tube Endobronchial blocker

Drugs	Benzodiazepine Etomidate General anaesthetic Inhalational anaesthetic Infiltration analgesia Ketamine Local anesthetic Methohexital Methoxyflurane Midazolam Neuraxial blockade Opiate Propofol Thiopental Thiopentone

Complications	Emergence delirium Allergic reactions Anesthesia awareness Local anesthetic toxicity Malignant hyperthermia Perioperative mortality Postanesthetic shivering Postoperative nausea and vomiting Postoperative residual curarization

Fields of study	Cardiothoracic Geriatric Oral sedation dentistry

Professions	Anesthesiologist Anesthesiologist assistant Nurse anesthetist Operating Department Practitioners Certified Anesthesia Technician Certified Anesthesia Technologist Anaesthetic technician

History	A.C.E. mixture Helsinki Declaration for Patient Safety in Anaesthesiology History of general anesthesia History of neuraxial anesthesia History of tracheal intubation

Organizations	American Association of Nurse Anesthetists American Society of Anesthesia Technologists & Technicians American Society of Anesthesiologists Anaesthesia Trauma and Critical Care Association of Anaesthetists of Great Britain and Ireland Association of Veterinary Anaesthetists Australian and New Zealand College of Anaesthetists Australian Society of Anaesthetists International Anesthesia Research Society

This article is issued from Wikipedia - version of the Friday, February 26, 2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.