1. Oxy/fuel gas welding and cutting equipment.
Safety Presentation
Oxy/fuel gas welding and cutting equipment.

2. DON’T LET THIS HAPPEN TO YOU !

5. Combustion Theory

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

7. Hazards . 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

8. Hazards 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
– Adequate risk assessment
– Never clean clothes with oxygen
-- Never hang coats or clothing on cylinders

9. Oxygen cylinder High Pressure Cylinder – 20,000 kpa or higher
Hollow, Seamless Steel Construction
Do Not Abuse Cylinder
Never Use For Other Than Intended Use
Report Any Damage to Supplier

10. Using Oxygen Open valves slowly Keep clean from grease or oil
Do not use teflon thread tape
Use in upright position
Keep cylinder secured properly
Beware of high pressure

11. Acetylene Cylinder Low Pressure – 1724 kpa @ 21.1o C
Thin Walls, Welded And Easily Damaged
Do Not Abuse – Can explode if damaged
Never Use A Damaged Cylinder
Report Damages To Supplier
Do Not Attempt To Repair Leaks
Move Leaking Cylinder Outside If Permitted
Must be stored and transported in upright position
Fusible
Plug
Monolithic Porous Filler Material

12. Acetylene Fires Most Fires Start In Valve Area – Check for Leaks
Fusible Metal Plugs Melt At 100o C
Flames – 5’ x 3’
Very Difficult To Extinguish
Evacuate Area
Call Fire Department

13. Using Acetylene Flammable – Keep Away From Sources of Ignition or Heat
Shock Sensitive – May Decompose Violently
Limited Withdrawal Rate – “1/7th Rule”
Asphyxiation
150 KPA Maximum Use Pressure
Do Not Use Copper Piping

14. Liquid Petroleum Gas LPG
Propane, Propylene Mapp®, Etc.
Liquid Under Pressure
Heavier Than Air
Not Shock Sensitive
Can Be Used Up To Full Cylinder Pressure
Liquid expands 270 times in volume when released to atmosphere

15. LPG Cylinder Hollow Welded Thin Wall Cylinder Vapor Space Above Liquid
Use Only While Standing Up
Low Pressure Less Than 500 PSIG, 3400 kpa
Has Fast Acting Valve
Open ½ to 1 Full Turn
Valve Safety Relieves and Resets
Never Use A Damaged Cylinder

16. Regulators
Oxygen
Acetylene
LPG
Argon
Nitrogen
CO2
Hydrogen

17. Regulators High Pressure Dial Gauge Low Pressure Dial Gauge Body
Bonnet
Adjustment Knob
Heavy Duty Adjusting Spring
Diaphragm
Encapsulated Seat Assembly
Inlet Spigot
Inlet Filter
Outlet Connector

18. Regulators Regulators are a pressure vessel
Fitted with high and low pressure gauges
Reduce high pressure to a useable low pressure
Are fitted with safety devices
Are colour coded
Must be marked with Aust Standards AS4267
Must have maximum working pressure
Are designed for specific gases

19. Hoses Are colour coded----Blue---Oxygen Orange—LPG
Red----Acetylene
Orange—LPG
Must comply with Aust Standards AS1335
Maximum length is 15 meters
Maximum working pressure is 1200 kpa
Are sized to suit flow requirements of equipment being used

20. Attachments & mixers

21. Safety Devices CHECK VALVES Are the basic safety device
Prevents flash back accidents caused by “reverse flow”
-Flashbacks can cause the most serious accidents
Check valves can fail because of “dirt” or other contamination
-Keep equipment clean
-Check them periodically

22. Check Valves
CORRECT FLOW
REVERSE FLOW

23. Flashback Arrestors Flashback arrestors are the ultimate safety device
Prevent flashback travelling back to fuel or oxygen source
Come in different sizes to suit flow requirements of equipment being used
NB: A flashback arrestor does not stop a flashback from occurring , they only stop it travelling back to the fuel source

24. What is a flashback ?
A flashback occurs when a mixture of oxygen & fuel gas is ignited upstream of tip
An oxygen and acetylene flashback travels at 13.1 meters per second
80 % of flashbacks are caused by human error
Causes can be , wrong gas pressures , incorrect purging , blocked or wrong tip , wrong sized hose or flash arrestor.

25. What’s inside a flashback arrestor ?

26. Where do I fit flash arrestors ?
As close to the mixing point as possible
Minimum protection at hand piece only
Maximum protection at hand piece and regulator
Be care full , over protection can restrict flow , and actually cause a flash back
Check the gas flow requirements of the equipment before selecting the arrestors

27. What should I see on an arrestor ?
Brand and type
Flow directional arrow
Date installed or last tested
Australian Standards AS4603
Year of manufacture
Maximum working pressure

28. Leak 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).

29. Cutting Torches

30. Welding Flame Types
Carburizing Flame
Neutral Flame
Oxidizing Flame

31. Lighting Equal Pressure LPG Torches
Open Torch Valves 1/8 to ¼ Turn
Ignite Fuel Gas With Approved Igniter and Adjust Flame
Introduce Oxygen And Adjust To The Desired Flame
It is Permissible To Light The Flame With Both Gases Flowing , { sometimes necessary }
Adjusting For large or Heating Tips , increase fuel then oxy in successive steps

32. Lighting An Oxy/Acetylene Torch
Slightly Open Acetylene Valve And Light With An Approved Device
Root Flame and Clear Smoke
Open Oxygen Valve And Set Flame To Neutral
Sharp, Defined Inner Cone
Never Light Torch With Both Oxygen And Acetylene Flowing

33. Lighting Low Pressure Injector Torches
It is permissible to light torch with both gases flowing.
Use special purge sequence to clear system of mixed gases.
Open fuel gas valve ½ to ¾ turn.
Open oxygen valve slightly 1/8 to 1/4 turn.
Adjust to desired flame.
Adjusting for large or heating tips , increase fuel then oxy in successive steps.

34. Turning Off An Oxy/Acetylene Torch
Proper Sequence Checks Integrity of Torch Valves
Close Oxygen Valve First
Close Acetylene Valve Second
If Acetylene Valve is Leaking a Small Flame Will Continue Burning
If Oxygen Valve is Leaking, Torch Will “Pop” as Acetylene Valve Is Closed
If Either Valve Is Leaking, Repair Before Further Use

35. Turning Off Alternate Fuel Torches
Close Fuel Gas Valve First
Close Oxygen Valve Second
This Sequence Can Prevent The Operator From Being Burned
If Fuel Pressure is Great Enough - Check Valves At Initial Light Up By Turning Oxygen Off First

36. Shutting Down An Oxy/Fuel Torch
Overnight Or For An Extended Period of Time
Turn Off Torch
Close Cylinder Valves
Open Then Close Each Torch Valve Independently To Bleed Pressure
Back Regulator Adjusting Screw Out Until Loose
Store Hose and Equipment In a Clean Area Away From Potential Damage

37. THE END