Welding, Soldering, Brazing Max Akhterov Zettl Group Safety Talk 11/07/06

Welding Welding is a materials joining process which produces coalescence of materials by heating them to suitable temperatures with or without the application of pressure or by the application of pressure alone, and with or without the use of filler material. The American Welding Society AWS distinguishes the welding processes according to: Mode of energy transfer Influence of capillary attraction in effecting distribution of filler metal in the joint Groups of welding processes: Arc welding Brazing Oxyfuel Gas Welding Resistance Welding Solid State Welding Soldering Other

Hazards 1. Fumes and Gases 2. Electric Shock 3. Radiation 4. Noise 5. Fire and Burns

Fumes and Gases Fumes are solid particles which originate from welding consumables, the base metal, and any coatings present on the base metal. Possible effects of over-exposure (magnesium, copper, zinc, lead, chromium, etc.): Irritation of eyes, skin, respiratory system Symptoms: nausea, headaches, dizziness, metal fume fever manganese overexposure can affect the central nervous system resulting in impaired speech and movement In confined spaces the gases might displace breathing air and cause asphyxiation How to avoid: Do not breathe the fumes Use respiratory protection Use enough ventilation or exhaust Be sure the breathing air is safe

Electric Shock The voltage used in welding: 120 – 575 V The current used in welding: 150 – 500 A Possible effects of electric shock: Spasms Burns Muscle paralysis Death How to avoid: Properly install and ground the equipment Wear dry, hole-free, insulating gloves and protective clothing Insulate yourself from the work piece and ground

Radiation Radiation is electromagnetic energy given off by the arc or flame that can injure eyes and burn skin. Operator does not see ultraviolet and infrared radiation. Radiation is often silent and undetected, yet injury occurs. Two type of radiation: Ionizing, Nonionizing. Possible effects of radiation: Skin burns Eye damage Skin cancer Symptoms: “sand in the eyes”, feeling of pressure in the eyes, tearing, photophobia How to avoid: Use welding helmet with correct shade of filter plate Protect skin with adequate gloves and clothing Be aware of reflections from welding arcs

Noise In welding noise may result from the process, the power source, or other equipment. Excessive noise is a known health hazard. Possible effects of noise: Loss of hearing that may be either full or partial and either temporary or permanent Hearing loss may be a temporary threshold shift from which the ears may recover if removed from the noise source How to avoid: Shield the source where practical Reduce the intensity of the source Use earmuffs

Fire and Burns Welding processes produce molten metal, sparks, slag, and hot work surfaces. These can cause fire or burns. How to avoid fire: Remove combustible materials for a minimum radius of 10.7 meters around the work area Cover or block all openings, such as doorways, windows, cracks, or other openings with fire resistant material Do not weld on or cut material having a combustible coating or internal structure How to avoid burns: Wear dry, hole-free insulating gloves Wear oil-free protective garments such as leather gloves, heavy shirt, cuffless pants, high shoes, and a cap Use approved helmets and safety goggles

Personal Protective Equipment Respiratory protection

Personal Protective Equipment Eye safety Safety eyewear should always be worn under the welding helmet to protect against flying debris when the helmet is raised to inspect work and when engaged in other welding activities, e.g. grinding, hammering.

274 Le Conte Hall Oxy-fuel welding and cutting safety (flame temperature 2000 C): Before using an oxyhydrogen setup, ensure that flammable materials such as grease, oil, paint, sawdust, etc are cleared from the area Use enough ventilation or exhaust Shaded goggles with enclosed sides to protect your eyes from glare sparks and splatter Wear leather gloves to protect your hands from burns. Clothes and shoes/boots appropriate for welding.

Soldering Soldering safety (about 400°C): Work only in well-ventilate areas Use soldering support Avoid touching the mains flex with the tip of the iron Always return the soldering iron to its stand when not in use Wash your hands after using solder

Resources EHS 0243 - Soldering Awareness Training The American Welding Society: http://aws.org/w/s/technical/facts/index.html Welding Guideline: www.gov.mb.ca/labour/safety/pdf/welding_guide.pdf