View
34
Download
0
Category
Tags:
Preview:
DESCRIPTION
Work Area. Area Should be Clear and Free of Combustibles Area Should Be Well Ventilated Fire Extinguishers Should Be Available Area Should Be Free of Open Arcs or Flames Fireproof Blankets and/or Screens Are Suggested. Personnel Protection. Wear Approved Eye Protection - PowerPoint PPT Presentation
Citation preview
Work Area
Area Should be Clear and Free of Combustibles
Area Should Be Well Ventilated Fire Extinguishers Should Be Available Area Should Be Free of Open Arcs or
Flames Fireproof Blankets and/or Screens Are
Suggested
Personnel Protection
Wear Approved Eye Protection Wear Flame Resistant Clothing Wear Long Sleeves, Pocket Flaps and N
o Cuffs Wear Approved Foot Gear Wear Approved Hand Protection
2
Proper Eye ProtectionLENS SHADES SELECTION
FOR OXYGEN FUEL GAS APPLICATIONS
Operation Material Size(inches)
Minimum Protective
Shade numberRecommended Shade Number*
Oxygen Fuel Gas Welding
< 1/8”1/8” to ½”
> ½”
456
4-55-66-8
Oxygen Fuel Gas Brazing 3 3-5
Air Fuel Gas Soldering 2 2-4
Oxygen Fuel Gas Cutting
< 11” to 6”
6
345
3-44-55-6
*As a rule of thumb, start with a shade that is too dark to see the weld or cutting zone.Then go to a lighter shade, which gives sufficient view of the weld or cutting zone without going below the minimum.
2A
2B
Proper Attire
Hard Hat with Visor Turned to the Back
Long Sleeve Shirt Gauntlet Leather
Welding Gloves
Industrial Quality Face Shield
Pants without CuffsHightop Leather Boots
(Steel Toes Recommended)
Oxygen Gas
Considered by Many as The Most Dangerous Gas
Know the Difference Between Oxygen and “Air”
Does Not Burn Itself, But Causes Other Materials To Burn More Vigorously
Heat of Recompression – Open Valve Slowly Keep Away From Combustibles – Especially
Oil Do Not Saturate Clothing, etc.
3
Combustion Theory
EQUILIBRIUM
3A
EQUILIBRIUM
Courtesy of CGA9A
Oxygen Cylinder
High Pressure Cylinder – 2200 PSIG orHigher
Hollow, Seamless Steel Construction
Do Not Abuse Cylinder Never Use For Other
Than Intended Use Report Any Damage
to SupplierOxygen Cylinder
High Pressure Hazard
Cap
Valve
ContentsVigorouslySupportsCombustion
4
Oxygen Cylinder Valve Compressed Gas Association
(CGA) 540 Stuck Valve – Valve Wrench
Only/Call Supplier High Pressure Safety
- Do Not Hang Objects On Cylinder
- Never Tamper With Valve Construction
- Heat Source Can “Blow” Safety
Only Fully Open or Fully Closed
Report Any Leaking or Damaged Valve to Supplier
To Oxygen Regulator
From Oxygen Cylinder
Upper Valve Seat
Lower Valve Seat
5
CGA 540
Burst Disc
Safety
Moving Oxygen or Other High Pressure Cylinders
6
Moving Cylinders Not In use:– Must Have Caps On– Do Not Lift – Roll on
Bottom Edge– Use An Approved Carrier
Moving Cylinders That Are In Use (Regulators Attached)– Must Be In An Approved
Carrier!
Using Oxygen And Other High Pressure Cylinder
Gases
7
Secure Cylinder In A Cart Or to Strong Permanent Structure
Do Not Use Near Flame, Flammables, Open Arc, Etc.
Use Only In An Upright Position Use Only In A Well Ventilated Area Always Inspect Cylinders For Damage Valve Fully Opened or Closed
Acetylene Gas
Calcium Carbide and Water Unstable and Highly Flammable Shock Sensitive Lighter Than Air Not to be used above 15 PSIG
8
Acetylene Cylinder Is Unique
Not Hollow –Acetone in Porous Monolithic Filler Material
Should Only Be Used And Stored Upright
Has Fast Acting ValveOpen ½ - 1 Full Turn
Has “Fusible Plugs” (212o F)
9
Acetylene Cylinder
Low Pressure – 250 PSIG @ 70o F Thin Walls, Welded And Easily Damaged Do Not Abuse – Can Explode If Abused Do Not Use For Other Than The Intended Use Never Use A Damaged Cylinder
– Report Damages To Supplier– Do Not Attempt To Repair Leaks– Move Leaking cylinders Outside If Permitted
10
Using Acetylene
Flammable – Keep Cylinders Away From Sources of Ignition or Heat Shock Sensitive – May Decompose Violently Limited Withdrawal Rate – “1/7th Rule” Asphyxiation 15 PSIG Maximum Use Pressure Do Not Use Copper Piping
11
Acetylene Fires
Most Fires Start In Valve Area – Check for Leaks Fusible Metal Plugs Melt At 212o F Flames – 5’ x 3’ Very Difficult To Extinguish Evacuate Area Call Fire Department
12
Alternate Fuels Propane, Propylene, Etc. Liquid Under Pressure Heavier Than Air Not Shock Sensitive Can Be Used Up To Full Cylinder Pressure Limited Withdrawal Rate – Dependent Upon Cylinder
Size, % Full and Ambient Temperature
8A
Liquid Petroleum Gas (LPG)Cylinder
Hollow, Welded, Thin Wall Cylinder Vapor Space Above Liquid
– Use Only While Standing Up Low Pressure Less Than 500 PSIG Has Fast Acting Valve
– Open ½ to 1 Full Turn
Valve Safety Relieves and Resets Never Use A Damaged Cylinder
From LPG Cylinder
To LPGRegulator
Valve Seat
Packing Nut
Handwheel
Valve Safety
9A
CGA 510 Valve
From LPG Cylinder
To LPGRegulator
Valve Seat
Handwheel
Valve Safety
Packing Nut
Oxy/Fuel EquipmentEquipment Set Up
Secure Cylinders Before Removing Caps “Crack” Oxygen Valve and Wipe Fuel Gas Valve With
a Clean Cloth Attach Regulators With Smooth Jawed Wrench Back Out Adjusting Screws Torch Valves Must Be Closed Tighten Wrench Connections According To Manufact
urers Instructions Inspect and Test Equipment
13
NEVER REMOVE THE VALVE PROTECTION CAP UNTIL CYLINDER IS
SECURED PROPERLY
6A
Secured Cylinders
13A
Tighten all connections with smooth jaw wrench
13B
Equipment Inspection
Look For Any Physical Damage Look For Other Signs of Abuse or Improper Use Look For Contamination – Oil, Dirt, etc. Clean, Replace Or Repair Before Use
14
Equipment Testing
Properly Tighten All Connections and Check To See If All Valves Are Closed
Stand To The side And Open Valves Slowly Check For Leaks
– Use Approved Bubble Solution or Pressure Test
Fix Any And All Leaks Before Proceeding
15
Before Lighting Oxy/Fuel Gas Torches
Make Sure All Valves Are Closed And Regulator Adjusting Screws Are Backed Out Set Gas Pressures According to the Manufacturers Tip
Charts Open Then Close Each Gas Valve Independently To
“Bleed” The System
Set Pressures “At Flow”
16
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
17
Welding Flame Types
17A
Carburizing Flame
Neutral Flame
Oxidizing Flame
Lighting Equal Pressure Torches Using Alternate Fuel Gases
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
– “Star Pattern” or Sound – Tip Edge Touching Plate
It is Permissible To Light The Flame With Both Gases Flowing– Sometimes it is Necessary
Adjusting For Large or Heating Tips:– Increase Fuel Then Oxygen In Successive Steps
17B
Lighting Low Pressure Injector Torches
It is Permissible To Light Torch With Both Gases Flowing Use Special Purge Sequence To Clear The System of
Mixed Gases Open Fuel Gas Valve ½ to ¾ Turn Open Oxygen Valve Slightly 1/8 to ¼ Turn Ignite Flame With An Approved Igniter Adjust To Desired Flame
– Tip Edge Touching Plate– “Star Pattern” or Sound
Adjusting For Large or Heating Tips:– Increase Fuel Then Oxygen In Successive Steps
17C
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
18
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
18A
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
19
Check Valves and Flashback Arrestors
CHECK VALVES Are a one way valve that stops the reverse flow of
gases
FLASHBACK ARRESTORS Have a special element, sintered metal filter, that can
quench a flame Generally also include a check valve
20
Check Valves and Flashback Arrestors
CHECK VALVES
Are the basic safety device
Prevents flash back accidents caused by “reverse flow” -Flashbacks can cause the most serious injuries
Check valves can fail because of “dirt” or other contamination
-Keep equipment clean -Check them periodically
21
Checkvalves
21A
HOW THEY WORK…
CORRECT FLOW REVERSE FLOW
Check Valves and Flashback Arrestors
FLASHBACK ARRESTORS Flashback arrestors are the ultimate safety device
Usually have a check valve built into it, but, can also stop a flame
-The check valve can fail because of contamination
The Heat sink element will absorb heat from a fire
The element should also be kept free of contamination and checked periodically
22
Torch vs Regulator Flash Back Arrestors
Where should Check Valves and Flashback Arrestors be Mounted
The Golden Rule: “Mount them as close to the point of mixing as possible”
Torch Mount Gives the best and most protection
May be inconvenient for the operator
Cannot be used for “high flow” applications
Are subjected to more abuse
23
Mount at the Torch vs Regulator
-continued
Regulator Mount Should use check valves at the torch also
High flow types are physically too large for torch
Take less abuse because they are out of the way
Do Not Use Both Too much restriction
Could cause other safety problems
24
Recommended