HANDLING HIGH PRESSURE CYLINDERS. Sources T. Joiner (ed.). 2001. NOAA Diving Manual - Diving for Science and Technology, Fourth Edition. Best Publishing

HANDLING HIGH PRESSURE CYLINDERS

Sources

• T. Joiner (ed.). 2001. NOAA Diving Manual - Diving for Science and Technology, Fourth Edition. Best Publishing Company, Flagstaff, Arizona.

• Bill High, notes from PSI Cylinder Inspection Course

• US Code of Federal Regulations Title 49: 172.700

Goal of This Training

• To increase your safety and the safety of those around you by familiarizing you with the policies and proper procedures for handling and filling cylinders containing high pressure gas

Objectives

• After completing this training module you will be able to:– Identify the regulating bodies regulating

hazardous materials training for handling high pressure cylinders and explain the regulations as they pertain to scientific diving

– Define a high pressure cylinder as it relates to diving

Objectives

• After completing this training module you will be able to:– Identify and explain cylinder markings

for steel and aluminum scuba cylinders– List 25 safe handling procedures for

high pressure cylinders– Define the parts of a fill station and list

procedures for filling high pressure cylinders common to all fill stations

Regulation

• In the US:– The Department of Transportation (DOT)

regulates transport of high pressure cylinders

– The Department of Labor, Occupational Safety and Health Administration (OSHA) regulates safety in the workplace

Regulation

• The Code of Federal Regulations (CFR Title 49: 172.700) mandates employees of companies involved in commerce who handle compressed gas cylinders to receive appropriate safety training.– A new hire should receive this training

within 90 days of hiring– Training should be repeated every three

years

Regulation

• Discussions with US DOT have determined that most organizations involved in scientific diving are not involved in commerce and are exempt from the three year retraining updates

• Local regulations or standards may re-impose this requirement

Regulation

• AAUS and NOAA scientific diving standards require all scientific divers to receive hazardous materials training for handling high pressure cylinders

High Pressure Cylinders

• The capacity of a cylinder is the amount of gas at surface pressure that can be compressed into the cylinder at its rated pressure– This capacity is usually expressed in

standard cubic feet or standard liters of gas• Cylinders with capacities from 26 standard

cubic feet to over 100 standard cubic feet are used in scuba diving

High Pressure Cylinders

• Scuba cylinders are generally made of steel or aluminum

• Cylinders used in diving fill to working pressures ranging from 1,800 to 3,500 psi (124 to 241 bar) or greater

Cylinder Markings

• Data describing the cylinder must be clearly stamped on the shoulder of the cylinder

Image courtesy Best Image courtesy Best PublishingPublishing

Cylinder Markings

• The precise manufacturing specifications of cylinders have been dictated by:– The Interstate Commerce Commission

(ICC) until 1970– The Department of Transportation (DOT)

after 1970– The TC/DOT (Transport Canada and DOT)

most recently dictates specifications for aluminum cylinders

Steel Cylinder Markings


Steel Cylinder Markings

• DOT (Department of Transportation – may also read ICC if cylinder predates 1970)

• 3AA (indicates steel construction) • Service pressure• Serial number • Cylinder manufacturer’s symbol• Hydrostatic test date

Aluminum Cylinder Markings


Aluminum Cylinder Markings

• DOT (or ICC)• 3AL (indicates aluminum

construction)• Service pressure • Serial number• Service volume • Manufacturer• Hydrostatic test date

Safe Handling Procedures

• Treat all cylinders designed to hold high pressure gas with respect

• Do not drop cylinders


• Wear shoes when working around cylinders

• Have a clear path to avoid tripping or knocking over cylinders or other equipment


• Cylinders are heavy and awkward; use proper lifting techniques and dollies to minimize the risk of personal injury


• Handle charged cylinders carefully – handling by the valve or body is preferred– handling by straps or backpack may

allow the cylinder to slip or drop• Cylinders should be stored at

temperatures not to exceed 130o F (54 C)


• Store charged cylinders in an upright position in a cool shady place and away from flammable materials

• Secure cylinders properly to prevent falling or rolling

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• While in transit, cylinders should be secured from rolling– Preferably in a rack in the upright

position

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• Open cylinder valves slowly• Do not put your body in the gas

stream– High pressure can force gas through the

skin and into the body; bubbles in the circulatory system could result in an embolism

– Injuries of this nature are not uncommon, so please keep out of harms way


• Cylinders that appear to be damaged by fire or physical abuse should be removed from service


• Scuba cylinders should receive a visual inspection by a qualified inspector annually

• A cylinder with signs of damage or that has been totally emptied, should receive a visual inspection before being put back in service


• Internal inspections, hydrostatic tests, and repair work should be performed only by trained technicians

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• Remove cylinder boot frequently to inspect for corrosion– Boots that inhibit rapid draining and

drying should not be used because they allow water to remain in contact with the cylinder, forming corrosion


• A cylinder that has been condemned during the visual inspection or hydrostatic testing process may never be returned to service

• Condemned cylinders should be made unserviceable (i.e. cut in two, hole drilled in the wall, threads destroyed, etc…)


• Do not use any cylinder that:– Is aluminum and has a rounded bottom– Have the manufacturing codes SP6576,

SP6688, or SP890 stamped into the cylinder

– Have large dents, bulges, or lines of corrosion

– Do not have a proper pressure relief device (burst disc)


• Do not use any cylinder that:– Have manufacturing codes SP6498,

E6498, SP7042, or E7042 stamped into the cylinder unless the cylinder is also stamped with the code 3AL• These were special aluminum alloys that

were given the 3AL rating at a later date


• Do not totally empty a cylinder without cause– Always try to leave 300 to 500 psi in the

cylinder– Empty cylinders should be internally

visually inspected by a trained technician prior to re-filling


• Regulators or gauges may fail when a cylinder valve is opened – it is important to stand to the side rather than in the line of discharge to avoid the blast effect in case of failure

Photos courtesy Dave PencePhotos courtesy Dave Pence


• Do not look directly at the face of any pressure gauge when turning on the cylinder because of the possibility of a blowout

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Fill Stations and Filling Cylinders

• Diving cylinders and associated high pressure equipment are manufactured and tested to standards in order to ensure a high degree of safety when they are properly used and maintained


• Manufacturing standards and maintenance requirements do not eliminate the possibility of a catastrophic failure that could result in serious injury or death

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• An 80 cubic foot cylinder filled to 3000 psi (207 bar) has in excess of one million pounds of kinetic energy; sufficient power to blow apart brick walls or destroy vehicles

Photo courtesy Photo courtesy connected.bc.ca/~baquatics/index.htmconnected.bc.ca/~baquatics/index.htm


• 90% of all cylinder explosions occur during the filling process

• Operator error has been linked to many of these incidents

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• Properly trained and attentive operators reduce their risk of being involved in a catastrophic incident

• Be familiar with the equipment you are working with and follow inspection requirements and safe operating procedures


• A fill station consists of a source of high pressure gas, high pressure lines called whips that connect the gas source to the cylinders being filled, and valves and gauges to control and monitor the filling process


• Fill stations come in a wide variety of configurations, the specifics of operating a given system are beyond the scope of this presentation and require additional training


• Compressor basics:– High pressure compressors capable of

producing breathing grade gas intake air, compress the air through a series of stages to increase the pressure, and filter the gas to remove impurities and excess moisture

Photos courtesy Photos courtesy Bauerair.comBauerair.com


• Compressor basics:– Each compressor has its own operational

and maintenance requirements, but items common to all units include: • Checking oil levels prior to startup• Monitoring compressor hours and filter life• Monitoring the compressor intake to assure a

proper air source, and monitoring stage pressures

• Keeping a log of regular maintenance and adhering to a maintenance schedule


• Storage banks take two forms:– A series of cylinders connected by

manifold to produce a desired storage capacity

– Or a single large storage cylinder such as a recycled submarine ballast tank• Cylinders connected by manifold have the

advantage of allowing cascade filling• A single large storage cylinder can offer the

advantage of not requiring periodic hydrostatic testing


• Storage banks have specific pressure limitations and are secured to prevent them from falling– Banked pressures of 4,500 psi (310 bar)

are common

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• Cascade filling involves equalizing the pressure in the cylinder being filled with the pressure in a single cylinder in a series of storage cylinders, moving to the next cylinder in the series and repeating the process until the desired pressure is reached

• Cascade filling is the most economical use of banked gas


• Fill station valves can be of a metering or ball valve design– A metering valve provides for slow and

controlled pressure adjustments– A ball valve is either open or closed

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Metering ValveMetering Valve Ball ValveBall Valve


• Caution should be taken when using fill panels employing ball valves, a rapid pressure spike can increase the risk of a fire in the presence of gases with high oxygen content

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• High pressure lines:– Pipes and hoses that carry high pressure

gas should be secured approximately every two feet and regularly inspected

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• Gauges:– Gauges that are used on the fill whips

and yokes are not calibrated or tested

– Gauges in the fill panel are tested and calibrated

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• The Fill Station Operator has the responsibility to reject cylinders that do not meet standards

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• Before filling a cylinder:– Verify it has valid ICC or DOT stampings

– Check for a current Hydrostatic Test Stamp• Hydrostatic testing must be done every five

years

Photos courtesy Steve Photos courtesy Steve SellersSellers


• Before filling a cylinder:– Verify a current visual inspection sticker

– Verify it has a valve with a pressure relief device

– Check that there is air/gas in the cylinder



• Before filling a cylinder:– Check the rated pressure of the cylinder

– Verify it has a valve O-Ring (yoke style valves)



• Before filling a cylinder:– Determine if the cylinder has a yoke or

DIN valve and that the fill station has the necessary adaptors to allow for filling



• Before filling a cylinder:– Check the pressure in the cylinder and

its contents (air, nitrox, etc.)• Cylinders containing gas mixtures other than

air should not be allowed to equalize pressure through the fill whips with cylinders not containing the same gas; doing so modifies gas mixtures in all the cylinders and could compromise the safety of unsuspecting divers using them


• Before filling a cylinder:– Verify the general condition of the

cylinder• On steel cylinders, strike the cylinder with a

blunt object; it should sound like a bell, if not, don’t fill it

• No visual signs of dents, bulges, scrapes, or line corrosion

– Verify the fill setting on the fill panel regulator (if present)

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• Do not fill high-pressure cylinders if the date of the last hydrostatic test has expired (five years for steel and aluminum cylinders) or if more than one year has passed since the last formal visual inspection



• Reject cylinders with the following markings or conditions:– SP6576– SP6688, SP890– SP6498, E6498, SP7042, E7042– All round bottom aluminum cylinders– Steel, non-galvanized, vinyl coated

cylinders


• Only individuals trained in the handling and filling of high pressure cylinders should be in the room when cylinders are being filled

• Maintain an organized fill area, keep a clear path in and out and secure cylinders after filling


• Preparing to fill:– Open cylinder valve to blow out

dust/water– Attach the fill whip to the valve– Close the whip bleed valve and open the

cylinder valve• If filling multiple cylinders containing the

same gas, open all cylinder valves and equalize the pressure between cylinders

– Open the fill whip valve – Open supply valve

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• Charge cylinders at 300-600 psig/min (20-41 bar/min) to prevent excessive heat buildup

• Never exceed the maximum allowable pressure for any particular cylinder

• Never perform maintenance or repairs on a cylinder valve while the cylinder is charged

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• A 3000 psi (207 bar) cylinder should take 5 to 10 minutes to fill

• Aluminum alloy cylinders should never be filled in excess of marked service pressure, and steel cylinders without a plus (+) after the current hydrostatic test date should also not be filled over their marked service pressure


• Assure any cylinders filled are properly labeled with appropriate contents labels and that any logs have been filled out as required by local procedures or standards


• When the filling process is complete, bleed excess pressure from the fill whips, close all valves, shut off power to the compressor, and secure the fill station per local procedures


• To help ensure safety during the filling process, considered the following:– Placing the fill station away from work

areas– Consulting with an engineer before

constructing a cylinder explosion diversion device

– Configuring controls away from the cylinder fill area


• Safety considerations continued:– Secure high-pressure hoses and fittings

at close intervals– Locate the fill station away from critical

building structural support and walls; provide a physical barrier between fill station operator and cylinders during filling

– Use an energy deflector to send explosive force in a safe direction


• Safety considerations continued:– Regularly inspect compressor filters and

piping– Allow only trained, authorized persons

to work at the fill station– Post operating procedures and safety

instructions– Proper labeling of all valves, gauges,

etc…

Study Questions

• Use the following study questions to review some of the information presented in this self study module. When you are finished you can print out your study questions results.

Self Study Questions

_____ require all scientific divers to receive hazardous materials training for handling high pressure cylinders.

• AAUS and NOAA scientific diving standards

• CFR Title 29: 1910 Sub Part T• OSHA• Individual State's Department of

Transportation


_____ require all scientific divers to receive hazardous materials training for handling high pressure cylinders.

• AAUS and NOAA scientific diving standards

• CFR Title 29: 1910 Sub Part T• OSHA• Individual State's Department of

Transportation


DOT regulations found in 49 CFR 172.700 mandate training requirements for employees of companies involved in commerce who handle compressed gas cylinders.A. TrueB. False


DOT regulations found in 49 CFR 172.700 mandate training requirements for employees of companies involved in commerce who handle compressed gas cylinders.A. TrueB. False


The codes 3AA 2250 PST 4~08+ stamped into the neck of a cylinder indicate:

• This is a steel cylinder with a rated working pressure of 2250 psi, manufactured by Pressed Steel, hydrostatically tested in April of 2008, and capable of being over filled by 10%.

• This is an aluminum cylinder with a rated working pressure of 2250 psi, manufactured by Pacific Scuba Tanks, hydrostatically tested in April of 2008, and capable of being over filled by 10%.

• The serial number of the cylinder.• This is a steel cylinder with a rated working pressure of 2250

psi, manufactured by Pressed Steel; last visually inspected in April of 2008, and capable of being over filled by 10%.


The codes 3AA 2250 PST 4~08+ stamped into the neck of a cylinder indicate:

• This is a steel cylinder with a rated working pressure of 2250 psi, manufactured by Pressed Steel, hydrostatically tested in April of 2008, and capable of being over filled by 10%.

• This is an aluminum cylinder with a rated working pressure of 2250 psi, manufactured by Pacific Scuba Tanks, hydrostatically tested in April of 2008, and capable of being over filled by 10%.

• The serial number of the cylinder.• This is a steel cylinder with a rated working pressure of 2250

psi, manufactured by Pressed Steel; last visually inspected in April of 2008, and capable of being over filled by 10%.

Self Study QuestionsIt is June 2008; a fill station operator conducting a

pre-filling survey of a cylinder finds the hydrostatic test dates of 2 98+ and 10 04. The cylinder has a current VIP sticker, all other required markings, and shows no signs of dents, bulges, scrapes or line corrosion. The fill station operator:

• can fill the cylinder, but only to the rated working pressure since the current hydrostatic test mark does not have a +.

• should not fill the cylinder because the current hydrostatic test mark does not have a +.

• should not fill the cylinder because the current hydrostatic test has passed the five year limit for the test.

• can fill the cylinder to a pressure 10% greater than the cylinder's rated working pressure because of the presence of the + on the cylinder.

Self Study QuestionsIt is June 2008; a fill station operator conducting a

pre-filling survey of a cylinder finds the hydrostatic test dates of 2 98+ and 10 04. The cylinder has a current VIP sticker, all other required markings, and shows no signs of dents, bulges, scrapes or line corrosion. The fill station operator:

• can fill the cylinder, but only to the rated working pressure since the current hydrostatic test mark does not have a +.

• should not fill the cylinder because the current hydrostatic test mark does not have a +.

• should not fill the cylinder because the current hydrostatic test has passed the five year limit for the test.

• can fill the cylinder to a pressure 10% greater than the cylinder's rated working pressure because of the presence of the + on the cylinder.

Self Study QuestionsIt is November 2008; a fill station operator conducting a

pre-filling survey of a cylinder finds the hydrostatic test dates of 2 97 and 10 03. The cylinder has a VIP sticker dated 10/07. It has the stamp 3AL, along with all other required markings, and shows no signs of dents, bulges, scrapes or line corrosion. (Select all that apply)

• The cylinder is "out of hydro"; it has been longer than five years since the last hydrostatic test.

• This cylinder is within its second hydrostatic test period.• The cylinder does not have a current VIP.• This is a steel cylinder.• This is an aluminum cylinder.• The cylinder has a current VIP.• The fill station operator should fill this cylinder.• The fill station operator should not fill this cylinder.

Self Study QuestionsIt is November 2008; a fill station operator conducting a

pre-filling survey of a cylinder finds the hydrostatic test dates of 2 97 and 10 03. The cylinder has a VIP sticker dated 10/07. It has the stamp 3AL, along with all other required markings, and shows no signs of dents, bulges, scrapes or line corrosion. (Select all that apply)

• The cylinder is "out of hydro"; it has been longer than five years since the last hydrostatic test.

• This cylinder is within its second hydrostatic test period.• The cylinder does not have a current VIP.• This is a steel cylinder.• This is an aluminum cylinder.• The cylinder has a current VIP.• The fill station operator should fill this cylinder.• The fill station operator should not fill this cylinder.

Self Study QuestionsSafe handling procedures for high pressure

cylinders include: (select all that apply)• Wear shoes when working around cylinders.• Store charged cylinders in an upright position in a cool

shady place and away from flammable materials.• Handling cylinders by straps or backpack is preferred

to handling cylinders by the valve.• Cylinders that appear to be damaged by fire or

physical abuse should be removed from service.• Scuba cylinders should receive a visual inspection by

a qualified inspector annually.• Internal inspections, hydrostatic tests, and repair work

should be performed only by trained technicians.• A cylinder that has been condemned during the visual

inspection or hydrostatic testing process may be returned to service after repairs have been completed.

Self Study QuestionsSafe handling procedures for high pressure

cylinders include: (select all that apply)• Wear shoes when working around cylinders.• Store charged cylinders in an upright position in a cool

shady place and away from flammable materials.• Handling cylinders by straps or backpack is preferred

to handling cylinders by the valve.• Cylinders that appear to be damaged by fire or

physical abuse should be removed from service.• Scuba cylinders should receive a visual inspection by

a qualified inspector annually.• Internal inspections, hydrostatic tests, and repair work

should be performed only by trained technicians.• A cylinder that has been condemned during the visual

inspection or hydrostatic testing process may be returned to service after repairs have been completed.


_____ is the most economical use of banked gas.

• Cascade filling• Single bank filling• Filling directly from the compressor• The use of high pressure scuba

cylinders


_____ is the most economical use of banked gas.

• Cascade filling• Single bank filling• Filling directly from the compressor• The use of high pressure scuba

cylinders


Select all that apply to the valve pictured here:

• This is an example of a Ball valve• This is an example of a Metering valve• This valve provides for slow and controlled pressure adjustments• This valve is either open or closed providing no means of pressure adjustments


Select all that apply to the valve pictured here:

• This is an example of a Ball valve• This is an example of a Metering valve• This valve provides for slow and controlled pressure adjustments• This valve is either open or closed providing no means of pressure adjustments

Self Study QuestionsMatch the item with its counterpart:A. Cascade fillingB. A ball valveC. A metering valveD. 4,500 psiE. Allows for cascade fillingF. A single large storage cylinder such as a recycled submarine ballast tankG. 300-600 psi or 20-41 barH. 5 to 10 minutesI. About 30 minutes• Equalizing the pressure in the cylinder being filled with the pressure in a single

cylinder in a series of storage cylinders, moving to the next cylinder in the series and repeating the process until the desired pressure is reached.

• Is either open or closed.• Provides for slow and controlled pressure adjustments.• 310 bar• A series of storage cylinders connected by manifold to produce a desired

storage capacity.• Can offer the advantage of not requiring periodic hydrostatic testing.• The rate per minute for filling cylinders.• The amount of time it should take to properly fill a 3000 psi (207 bar) cylinder.• The amount of time it will take someone with a surface air consumption of 20

psi/minute to breathe 2500 psi from a scuba cylinder while diving in 99 feet of seawater.















































Select all of the items listed that the fill station operator should do before filling a cylinder:

• Verify the cylinder has valid ICC or DOT stampings• Check for a current Hydrostatic Test Stamp• Verify a current visual inspection sticker (within the past

year)• Verify the cylinder has a valve with a pressure relief device• Check that there is air/gas in the cylinder• Check the rated pressure of the cylinder• Check the pressure in the cylinder and its contents (air,

nitrox, etc.)• Verify the general condition of the cylinder• Open the bleed valve on the fill whip• Close the cylinder valve


Select all of the items listed that the fill station operator should do before filling a cylinder:

• Verify the cylinder has valid ICC or DOT stampings• Check for a current Hydrostatic Test Stamp• Verify a current visual inspection sticker (within the past

year)• Verify the cylinder has a valve with a pressure relief device• Check that there is air/gas in the cylinder• Check the rated pressure of the cylinder• Check the pressure in the cylinder and its contents (air,

nitrox, etc.)• Verify the general condition of the cylinder• Open the bleed valve on the fill whip• Close the cylinder valve


Putting part of your body in the air stream of an open high pressure cylinder valve can lead to embolism.

A.TrueB.False


Putting part of your body in the air stream of an open high pressure cylinder valve can lead to embolism.

A.TrueB.False


Preferably, cylinders should be transported and stored in a secure, upright position.

A.TrueB.False


Preferably, cylinders should be transported and stored in a secure, upright position.

A.TrueB.False


Caution should be taken when using fill panels employing _____ valves, a rapid pressure spike can increase the risk of a fire in the presence of gases with high oxygen content.

• metering• ball• J• K• yoke• DIN


Caution should be taken when using fill panels employing _____ valves, a rapid pressure spike can increase the risk of a fire in the presence of gases with high oxygen content.

• metering• ball• J• K• yoke• DIN


Fill Station Operator has the responsibility to reject cylinders that do not meet standards.

A.TrueB.False


Fill Station Operator has the responsibility to reject cylinders that do not meet standards.

A.TrueB.False


Only individuals _____ in the handling and filling of high pressure cylinders should be in the room when cylinders are being filled.

• trained• interested• participating• tasked


Only individuals _____ in the handling and filling of high pressure cylinders should be in the room when cylinders are being filled.

• trained• interested• participating• tasked

Documents

HANDLING HIGH PRESSURE CYLINDERS. Sources T. Joiner (ed.). 2001. NOAA Diving Manual - Diving for Science and Technology, Fourth Edition. Best Publishing