Oxy/fuel gas welding and cutting Oxy/fuel gas welding and cutting equipment.equipment.

Safety Safety PresentationPresentation

DON’T LET THIS HAPPEN DON’T LET THIS HAPPEN TO YOU !TO YOU !

Combustion TheoryCombustion Theory

HAZARDS!

1. Pressure 2. Flammability 3. Toxicity 4. Oxygen Compatibility 5. Oxygen Deficiency / Enrichment 6. Weight & Size6. Weight & Size

. Damage reduces cylinder safe working pressure.

– falling over – corrosion – bumps, impacts • Excessive heat increases pressure in

cylinder past safe working pressure. Prevention • Pressure safety devices in cylinder • Care when using, transporting &

storing cylinders

Hazards

HazardsHazards Oxygen Compatibility • material that will react with oxygen • oil, dust, grit Safeguards – never use oil & grease on cylinders – never use cylinders with dirty valves Oxygen Deficiency/Enrichment • Enrichment - oxygen release • Deficiency - oxygen replaced by asphyxiants Safeguards – Adequate risk assessment – Never clean clothes with oxygen -- Never hang coats or clothing on cylinders-- Never hang coats or clothing on cylinders

Oxygen cylinderOxygen cylinder

High Pressure Cylinder – 20,000 kpa or higherHollow, Seamless Steel ConstructionDo Not Abuse CylinderNever Use For Other Than Intended UseReport Any Damage to Supplier

Using OxygenUsing Oxygen

Open valves slowlyOpen valves slowly Keep clean from grease or oilKeep clean from grease or oil Do not use teflon thread tapeDo not use teflon thread tape Use in upright positionUse in upright position Keep cylinder secured properlyKeep cylinder secured properly Beware of high pressureBeware of high pressure

Acetylene CylinderAcetylene Cylinder Low Pressure – 1724 kpa @ 21.1Low Pressure – 1724 kpa @ 21.1oo C C

Thin Walls, Welded And Easily Thin Walls, Welded And Easily

DamagedDamaged

Do Not Abuse – Can explode if Do Not Abuse – Can explode if

damageddamaged

Never Use A Damaged CylinderNever Use A Damaged Cylinder Report Damages To SupplierReport Damages To Supplier Do Not Attempt To Repair Do Not Attempt To Repair

LeaksLeaks Move Leaking Cylinder Outside Move Leaking Cylinder Outside

If PermittedIf Permitted Must be stored and transported in Must be stored and transported in

upright position upright position

Fusible

Plug

Monolithic Porous Filler Material

Fusible

Plug

Acetylene FiresAcetylene Fires

Most Fires Start In Valve Area – Check Most Fires Start In Valve Area – Check

for Leaksfor Leaks

Fusible Metal Plugs Melt At 100Fusible Metal Plugs Melt At 100oo C C

Flames – 5’ x 3’Flames – 5’ x 3’

Very Difficult To ExtinguishVery Difficult To Extinguish

Evacuate AreaEvacuate Area

Call Fire DepartmentCall Fire Department

Using AcetyleneUsing Acetylene

Flammable – Keep Away From Sources of Flammable – Keep Away From Sources of

Ignition or HeatIgnition or Heat

Shock Sensitive – May Decompose ViolentlyShock Sensitive – May Decompose Violently

Limited Withdrawal Rate – “1/7Limited Withdrawal Rate – “1/7thth Rule” Rule”

AsphyxiationAsphyxiation

150 KPA Maximum Use Pressure150 KPA Maximum Use Pressure

Do Not Use Copper PipingDo Not Use Copper Piping

Liquid Petroleum Gas Liquid Petroleum Gas LPGLPG

Propane, Propylene Mapp®, Etc.Propane, Propylene Mapp®, Etc.

Liquid Under PressureLiquid Under Pressure

Heavier Than AirHeavier Than Air

Not Shock SensitiveNot Shock Sensitive

Can Be Used Up To Full Cylinder PressureCan Be Used Up To Full Cylinder Pressure

Liquid expands 270 times in volume when Liquid expands 270 times in volume when

released to atmosphere released to atmosphere

LPG CylinderLPG Cylinder Hollow Welded Thin Wall CylinderHollow Welded Thin Wall Cylinder

Vapor Space Above LiquidVapor Space Above Liquid Use Only While Standing UpUse Only While Standing Up

Low Pressure Less Than 500 PSIG, 3400 kpaLow Pressure Less Than 500 PSIG, 3400 kpa

Has Fast Acting ValveHas Fast Acting Valve Open ½ to 1 Full Turn Open ½ to 1 Full Turn

Valve Safety Relieves and ResetsValve Safety Relieves and Resets

Never Use A Damaged CylinderNever Use A Damaged Cylinder

RegulatorsRegulators

OxygenOxygen AcetyleneAcetylene LPGLPG ArgonArgon NitrogenNitrogen CO2CO2 HydrogenHydrogen

RegulatorsRegulators

High Pressure Dial GaugeLow Pressure Dial GaugeBodyBonnetAdjustment KnobHeavy Duty Adjusting SpringDiaphragmEncapsulated Seat AssemblyInlet SpigotInlet FilterOutlet Connector

RegulatorsRegulators Regulators are a pressure vesselRegulators are a pressure vessel Fitted with high and low pressure gaugesFitted with high and low pressure gauges Reduce high pressure to a useable low Reduce high pressure to a useable low

pressurepressure Are fitted with safety devicesAre fitted with safety devices Are colour codedAre colour coded Must be marked with Aust Standards Must be marked with Aust Standards

AS4267AS4267 Must have maximum working pressureMust have maximum working pressure Are designed for specific gases Are designed for specific gases

HosesHoses Are colour coded----Blue---OxygenAre colour coded----Blue---Oxygen

Red----AcetyleneRed----Acetylene Orange—LPGOrange—LPG

Must comply with Aust Standards Must comply with Aust Standards AS1335AS1335

Maximum length is 15 metersMaximum length is 15 meters Maximum working pressure is 1200 kpaMaximum working pressure is 1200 kpa Are sized to suit flow requirements of Are sized to suit flow requirements of

equipment being usedequipment being used

Attachments & mixersAttachments & mixers

Safety DevicesSafety Devices

CHECK VALVESCHECK VALVES Are the basic safety deviceAre the basic safety device Prevents flash back accidents caused Prevents flash back accidents caused

by “reverse flow”by “reverse flow” --Flashbacks can cause the most serious Flashbacks can cause the most serious

accidentsaccidents Check valves can fail because of Check valves can fail because of

“dirt” or other contamination“dirt” or other contamination -Keep equipment clean-Keep equipment clean -Check them periodically-Check them periodically

Check ValvesCheck Valves

CORRECT FLOW REVERSE FLOW

Flashback ArrestorsFlashback Arrestors

Flashback arrestors are the ultimate Flashback arrestors are the ultimate safety devicesafety device

Prevent flashback travelling back to Prevent flashback travelling back to fuel or oxygen sourcefuel or oxygen source

Come in different sizes to suit flow Come in different sizes to suit flow requirements of equipment being usedrequirements of equipment being used

NB: A flashback arrestor does not stop NB: A flashback arrestor does not stop a flashback from occurring , they only a flashback from occurring , they only stop it travelling back to the fuel source stop it travelling back to the fuel source

What is a flashback ?What is a flashback ?

A flashback occurs when a mixture of A flashback occurs when a mixture of oxygen & fuel gas is ignited upstream of oxygen & fuel gas is ignited upstream of tiptip

An oxygen and acetylene flashback An oxygen and acetylene flashback travels at 13.1 meters per secondtravels at 13.1 meters per second

80 % of flashbacks are caused by human 80 % of flashbacks are caused by human errorerror

Causes can be , wrong gas pressures , Causes can be , wrong gas pressures , incorrect purging , blocked or wrong tip , incorrect purging , blocked or wrong tip , wrong sized hose or flash arrestor.wrong sized hose or flash arrestor.

What’s inside a flashback What’s inside a flashback arrestor ?arrestor ?

Where do I fit flash Where do I fit flash arrestors ?arrestors ?

As close to the mixing point as possibleAs close to the mixing point as possible Minimum protection at hand piece onlyMinimum protection at hand piece only Maximum protection at hand piece and Maximum protection at hand piece and

regulatorregulator Be care full , over protection can restrict Be care full , over protection can restrict

flow , and actually cause a flash backflow , and actually cause a flash back Check the gas flow requirements of the Check the gas flow requirements of the

equipment before selecting the arrestorsequipment before selecting the arrestors

What should I see on an What should I see on an arrestor ?arrestor ?

Brand and typeBrand and type Flow directional arrowFlow directional arrow Date installed or last testedDate installed or last tested Australian Standards AS4603Australian Standards AS4603 Year of manufactureYear of manufacture Maximum working pressureMaximum working pressure

Leak Testing ProcedureLeak Testing Procedure Turn off hand piece. Turn on cylinder valve. Adjust regulator to normal working

pressure and pressurize hose. Note working pressure. Turn off cylinder valve. If pressure drops obviously over two

minutes then there is a leak. If the leak is not obvious, find it using

Nuprosnoop (not soapy water as it may contain oily residue).

Cutting TorchesCutting Torches

Welding Flame TypesWelding Flame Types

Carburizing Flame

Neutral Flame

Oxidizing Flame

Lighting Equal Pressure Lighting Equal Pressure LPG TorchesLPG Torches

Open Torch Valves 1/8 to ¼ TurnOpen Torch Valves 1/8 to ¼ Turn Ignite Fuel Gas With Approved Igniter and Ignite Fuel Gas With Approved Igniter and

Adjust FlameAdjust Flame Introduce Oxygen And Adjust To The Introduce Oxygen And Adjust To The

Desired FlameDesired Flame It is Permissible To Light The Flame With It is Permissible To Light The Flame With

Both Gases Flowing , { sometimes Both Gases Flowing , { sometimes necessary }necessary }

Adjusting For large or Heating Tips , Adjusting For large or Heating Tips , increase fuel then oxy in successive stepsincrease fuel then oxy in successive steps

LightingLighting An Oxy/Acetylene An Oxy/Acetylene TorchTorch

Slightly Open Acetylene Valve And Light Slightly Open Acetylene Valve And Light

With An Approved DeviceWith An Approved Device

Root Flame and Clear SmokeRoot Flame and Clear Smoke

Open Oxygen Valve And Set Flame To Open Oxygen Valve And Set Flame To

NeutralNeutral Sharp, Defined Inner ConeSharp, Defined Inner Cone

Never Light Torch With Both Oxygen And Never Light Torch With Both Oxygen And

Acetylene FlowingAcetylene Flowing

Lighting Low Pressure Lighting Low Pressure Injector TorchesInjector Torches

It is permissible to light torch with both It is permissible to light torch with both gases flowing.gases flowing.

Use special purge sequence to clear Use special purge sequence to clear system of mixed gases.system of mixed gases.

Open fuel gas valve ½ to ¾ turn.Open fuel gas valve ½ to ¾ turn. Open oxygen valve slightly 1/8 to 1/4 turn.Open oxygen valve slightly 1/8 to 1/4 turn. Adjust to desired flame.Adjust to desired flame. Adjusting for large or heating tips , Adjusting for large or heating tips ,

increase fuel then oxy in successive steps.increase fuel then oxy in successive steps.

Turning Off An Oxy/Acetylene Turning Off An Oxy/Acetylene TorchTorch

Proper Sequence Checks Integrity of Torch Proper Sequence Checks Integrity of Torch ValvesValves

Close Oxygen Valve FirstClose Oxygen Valve First Close Acetylene Valve SecondClose Acetylene Valve Second If Acetylene Valve is Leaking a Small Flame If Acetylene Valve is Leaking a Small Flame

Will Continue BurningWill Continue Burning If Oxygen Valve is Leaking, Torch Will If Oxygen Valve is Leaking, Torch Will

“Pop” as Acetylene Valve Is Closed“Pop” as Acetylene Valve Is Closed If Either Valve Is Leaking, Repair Before If Either Valve Is Leaking, Repair Before

Further UseFurther Use

Turning Off Alternate Fuel Turning Off Alternate Fuel TorchesTorches

Close Fuel Gas Valve FirstClose Fuel Gas Valve First Close Oxygen Valve SecondClose Oxygen Valve Second This Sequence Can Prevent The This Sequence Can Prevent The

Operator From Being BurnedOperator From Being Burned If Fuel Pressure is Great Enough - If Fuel Pressure is Great Enough -

Check Valves At Initial Light Up By Check Valves At Initial Light Up By Turning Oxygen Off FirstTurning Oxygen Off First

Shutting Down An Oxy/Fuel Shutting Down An Oxy/Fuel TorchTorch

Overnight Or For An Extended Period of Overnight Or For An Extended Period of TimeTime

Turn Off TorchTurn Off Torch Close Cylinder ValvesClose Cylinder Valves Open Then Close Each Torch Valve Open Then Close Each Torch Valve

Independently To Bleed PressureIndependently To Bleed Pressure Back Regulator Adjusting Screw Out Until Back Regulator Adjusting Screw Out Until

LooseLoose Store Hose and Equipment In a Clean Area Store Hose and Equipment In a Clean Area

Away From Potential DamageAway From Potential Damage

THE ENDTHE END