Oxyfuel Gas Welding Safety
TERMS AND DEFINITIONS • Fusion Welding • Joining of metal by heating the adjoining edges to the fusion or melting point and allowing them to flow or run together and then cool • Penetration • Distance from the original surface of the base metal to the point at which fusion ceases. • Base Metal • Metal to be welded
TERMS AND DEFINITIONSContinued • Alloy • Mixture with metallic properties composed of two or more elements of which, at least one, is a metal. • Inner Cone • Inner white part of a neutral flame. • Tack Weld • Short weld used for temporarily holding metal in place.
TERMS AND DEFINITIONSContinued • Back Fire • Momentary burning back of the flame into the tip. • Flame goes out with a loud snap or pop. • Flash Back • Fire inside the torch. • Indicated by a hissing or squealing sound • (Caution: this is a very dangerous condition. Shut down acetylene first and then the oxygen last.) • Causes of flash backs are : dirty tips or equipment, improper welding or cutting procedures. • Check Valves • Prevents the mixing of gases and removes the hazard of explosion.
Safety rules for Oxygen, Acetylene, and Oxy-acetylene welding equipment. • Support oxygen and acetylene cylinders in an upright position so they cannot be tipped over. • Note: Acetylene gas is in a liquid form in the cylinder and should be used in the vertical position so the acetone will not be withdrawn. If the tank is on it’s side it must stand for at least twice the amount of time it was on its side. • Before connecting regulators to the tanks, crack the valve in order to remove dust and dirt that may damage the regulators. • Note: Be sure to crack cylinder valves for a second before attaching regulators.
Safety Rules Continued • Release pressure-adjusting screws on regulator before opening the cylinder valve to prevent damage to the regulator and possible injury to the operator. • Stand to the side of tank and regulator, keeping the cylinder valve between operator and regulator, while opening cylinder valve.
Safety Rules Continued • Open cylinder valve SLOWLY. • Note: The oxygen cylinder valve is opened to full capacity. The Acetylene valve is opened ¾ of a turn only. • Do not use acetylene (in free state) at pressures above 15 psi • Note: Acetylene becomes unstable at pressures above 15 psi and becomes highly explosive. • Oxygen and Acetylene regulators should be set at a 7 to 3 ratio. • Note: Oxygen 20 psi, Acetylene 7 psi
Safety Rules Continued • Clear oxygen and acetylene passages individually before lighting torch. • Crack torch valves for each one separately before you light the torch. • Light Acetylene before opening oxygen torch valve. • Use only a striker, never a match or lighter.
Adjusting The Flame • Adjust the flame to a neutral flame. This is the desired flame for most welding applications. • There are 3 types of flames. • A. Neutral Flame • B. Oxidizing Flame • Carburizing Flame
Safety Rules Continued • Never use oil or grease on regulators, torches, or fittings. • : Oil or grease has a high attraction to oxygen and will unit with explosive violence. • Do not use oxygen as a substitute for compressed air • Use safety goggles, gloves, and protective clothing. • Keep gloves, hands, and clothing free from oil, grease, and fuels • Have CO2 or dry chemical type fire extinguishers available.
Safety Rules Continued • Test connections for leaks with a non-oil-based soapsuds, paint brush, and water. • Avoid lighting the torch or welding near combustible materials.
Safety Rules Continued • Never open the acetylene cylinder valve more than ¾ of a turn. • Always operate torch in a well ventilated place. • Never weld on containers that have been used for combustible materials. • Avoid breathing toxic fumes when welding.
Safety Rules Continued • Place steel caps on all gas cylinders when they are being moved or stored, to protect the valves. • Shut off cylinder valves when not in use for any length of time to reduce the possibility of leakage and strain on equipment.
PPE (Personal Protective Equipment) • Eye & Ear Protection • Welding Goggles with Proper Lens Shade Number • Welding Gloves & Optional Covering • Proper Attire for OFW, OFC, OFB, & AFS
Eye & Ear Protection Ear Plugs Goggles Safety Glasses Hearing Protection
Headgear Adjustable Head Gear Spare Cover Lens Cover Lens Filter Lens
Optional Covering Leather Welding Apron Leather Welding Jacket Leather Welding Gloves Leather Welding Cape Sleeves/Bib Leather Welding Trousers
Proper Attire Industrial Quality Safety Glasses Cap with Visor Turned to the Back Gauntlet Leather Welding Gloves Long Sleeve Shirt High Top Leather Boots(Steel Toes) Pants without Cuffs
Fumes & Gases • Welding or Cutting May Produce Hazardous Fumes & Gases • Leaking Gases May Cause Injury or Death • Use Ventilation To Keep Air Breathing Zone Clear & Comfortable • Use Special Care When Welding or Cutting In a Confined Area or on a Container • Do Not Weld or Cut Near Flammables
Radiation - UV, IR, & Visible • Oxyfuel UV/IR Rays Can Burn Eyes & Skin • Always Use Approved Eye Protection When Oxy FuelWelding or Cutting • Select an Appropriate Filter Lens for the Process & Application • Wear Appropriate Clothing Which Protects the Skin • Provide Non-Flammable Shielding to Protect Others
Fire or Explosion • Remove Flammable Materials From The Work Area • Keep a Fire Extinguisher in the Work Area • Wear Fire Retardant Clothing & a Hat When Welding or Cutting • Do Not Weld on Containers Which Have Held Combustible Materials or Closed Containers of Any Kind
Compressed Gas Hazards • Cylinders may Explode if Damaged • Keep Cylinders Upright &Chained to Support or Approved Carrier • Keep Cylinder Free from Sparks& Out of the Spark Zone • Never Allow Flames from a Torch to Come in Contact with a Cylinder or Hose
General Hazards in Work Area • Keep Gas Hoses, Materials & Tools Neatly Organized • Never Use Leaking or Faulty Equipment • Always Ensure ProperEnvironment & Ventilation • Do Not Weld or Cut in a Confined Area • Remove All Flammable Materials From the Work Area, Etc. • Keep All Equipment In Good Condition
Equipment needed for OFW • Oxygen Cylinder • Acetylene Cylinder • Regulators for both Acetylene and Oxygen • Hoses • Flash Arresters • Torch body • Torch Tip • Tip Cleaners • Striker
Acetylene Cylinder • Acetylene Cylinder • The valve is opened ¾ of a turn. • This is due to that acetylene can only be drawn off at a certain rate and any more is not needed. • Also this allows for a quick shutdown if something wrong happens. • Set the regulator pressure at 7 psi. Never let the pressure go over 15 psi. Acetylene becomes unstable at 15psi or higher.
Oxygen Cylinder • Oxygen cylinder • The oxygen cylinder should be opened completely. • This needs to happen due to the valve having a back seat valve. • The pressure needs to be set at 20 psi
What do the cylinders look like? High Pressure Hazard Safety Disc Flammable Monolithic Porous Filler Material Fusible Plugs Hollow Vigorously Supports Combustion 1/7th Rule Shock Sensitive Oxygen Cylinder Acetylene Cylinder
Types Cylinder Valves • Oxygen Cylinder Valve • CGA 540 • Acetylene Cylinder Valve • CGA 510 with hand knob • CGA 510 with Tee Wrench or Tank Wrench • CGA 300
Oxygen Cylinder Valves Handwheel CGA 540 Packing Nut Upper Valve Seat To Oxygen Regulator Lower Valve Seat Disc Ruptures If Pressure Goes Too High From Oxygen Cylinder
Acetylene Cylinder Valves CGA 510 CGA 300 Handwheel Packing Nut Upper Valve Seat To Acetylene Regulator To Acetylene Regulator Lower ValveSeat From Acetylene Cylinder From Acetylene Cylinder
Acetylene Cylinder Valves- Linde (Presti-Lite) To Acetylene Regulator CGA 510 Tank Wrench Tee Wrench Valve Stem Packing Nut Upper Valve Seat Lower Valve Seat From Acetylene Cylinder
Regulators Oxygen Regulator Fuel Gas Regulator 20 psi 7 psi
Which Regulator? • Single Stage Regulator • Use When Slight Rise in Delivery Pressure from Full to Empty Cylinder Condition Can Be Tolerated • Two Stage Regulator • Use When a Constant Delivery Pressure from Full to Empty Cylinder Condition is Required
Single Stage Regulator Adjusting Screw Bonnet Flexible Diaphragm Primary Spring Gas To Torch Gas From Cylinder Regulator Body Secondary Spring
Cutaway Bonnet Gas From Cylinder Cylinder Pressure Gauge Adjusting Screw Secondary Spring Primary Spring Capsule Flexible Diaphragm Working Pressure Gauge Gas To Torch Regulator Body
Two Stage Regulator Adjusting Screw Primary Spring Second Stage Regulator Body Bonnet Adjustable Second Stage Gas To Torch Gas From Cylinder Flexible Diaphragm Secondary Spring Primary Spring First Stage Pre-Set First Stage
Cutaway Regulator Body Gas From Cylinder Secondary Spring Cylinder Pressure Gage Bonnet Adjusting Screw Capsule Primary Spring Primary Spring Capsule Bonnet Flexible Diaphragm Working Pressure Gage Gas To Torch