Instructor s Guide. Safety and Technology Series Welding Safety. Introduction. Learning Objectives

Transcription

1 Safety and Technology Series Welding Safety Introduction This guide provides information to help you get the most out of the Welding Safety program of the Safety and Technology series. Welding Safety not only introduces different types of welding, it also describes the potential dangers each one poses, along with the steps trade professionals can take to ensure welding safety. Learning Objectives After viewing the program, students will be able to: Identify the potential dangers welding presents to trade professionals. Explain the differences among the most common types of welding metal inert gas, tungsten inert gas welding, rod, spot, and gas (oxy-fuel) welding. Recognize the dangers the most common types of welding (as well as cutting and brazing) pose. State the actions trade professionals must take to ensure safety when welding and using welding equipment WeldingSafety IG.indd 1 2/2/11 12:32 PM

2 Educational Standards This program content correlates with the following Electrical Competency Objectives of the National Center for Construction Education and Research (NCCER). Level One: MODULE Identify some common hazards in welding. 2. Explain and identify proper personal protection used in welding. 3. Demonstrate how to avoid welding fumes. 4. Explain some of the causes of accidents. 8. Demonstrate proper material handling methods. The competencies and objectives from the NCCER have been reprinted with permission. This program correlates with the National Science Education Standards National Committee on Science Education Standards and Assessment, National Research Council. Science as Inquiry Content Standard A: As a result of activities in grades 9-12, all students should develop: Abilities necessary to do scientific inquiry Understandings about scientific inquiry Physical Sciences Content Standard B: As a result of their activities in grades 9-12, all students should develop an understanding of: Structure of atoms Structure and properties of matter Chemical reactions Motions and forces Conservation of energy and increase in order Interactions of energy and matter Science and Technology Content Standard E: As a result of their activities in grades 9-12, all students should develop an understanding of: Abilities of technological design Understanding about science and technology National Science Education Standards, from the National Committee on Science Education Standards and Assessment and the National Research Council. Copyright 1996 by the National Research Council of the National Academy of Sciences. Reprinted with permission WeldingSafety IG.indd 2 2/2/11 12:32 PM

3 The activities in this Teacher s Guide were created in compliance with the following National Standards for the English Language Arts from the National Council of Teachers of English. Standard 7: Students conduct research on issues and interests by generating ideas and questions, and by posing problems. They gather, evaluate, and synthesize data from a variety of sources (e.g., print and non-print texts, artifacts, people) to communicate their discoveries in ways that suit their purpose and audience. Standard 8: Students use a variety of technological and information resources (e.g., libraries, databases, computer networks, video) to gather and synthesize information and to create and communicate knowledge. Standards for the English Language Arts, by the International Reading Association and the National Council of Teachers of English. Copyright 1996 by the International Reading Association and the National Council of Teachers of English. Reprinted with permission. The activities in this Teacher s Guide were created in compliance with the following National Education Technology Standards from the National Education Technology Standards Project. Standard 3: Research and Information Fluency. Students apply digital tools to gather, evaluate, and use information. Standard 4: Critical Thinking, Problem-Solving & Decision-Making. Students use critical thinking skills to plan and conduct research, manage projects, solve problems and make informed decisions using appropriate digital tools and resources. The National Education Technology Standards reprinted with permission from the International Society for Technology Education. Copyright Reprinted with permission. Program Overview This video covers the most important safety rules and protective equipment to use when performing MIG, TIG, arc, and gas welding. Welding helmets and their lens ratings, leather aprons and gloves, welding gas respirators, heat shields, and fire extinguishers are discussed, and various types of welders, including plasma cutters, are illustrated WeldingSafety IG.indd 3 2/2/11 12:32 PM

4 Main Topics Chapter 1: Introduction This introductory section gives examples of how different trade professionals weld as part of their job. It explains that the video will feature the most common types of welding metal inert gas, tungsten inert gas welding, rod, spot, and gas (oxy-fuel) welding and stress what must be done to properly weld different metals safely without injury to workers or others. Chapter 2: Basic Welding Processes Here, viewers learn about common welding processes and their respective tools and equipment. This segment also introduces welding techniques called cutting and brazing. Chapter 3: Arc Welding Radiation This section underscores the levels of welding light radiation that emerge from the different types of welding processes. It discusses the dangers this light poses, especially to the eyes and skin, and describes safety measures that include wearing helmets. Chapter 4: Welding Fumes In addition to discussing the harm (such as asphyxiation and unconsciousness) welding fumes can cause, this film segment recommends precautions that include reading OSHA guidelines for permissible fume exposure limits, as well as carefully reviewing Material Safety Data Sheets for the hazardous materials that welding produces. Chapter 5: Welding Fires and Explosions Here, viewers gain tips on how welders can protect themselves from welding-driven burns, fires, and explosions. Chapter 6: Gas Welding Safety Wearing welding goggles, using a respirator when welding in poorly ventilated areas, and properly shutting down welding equipment are among several precautionary measures this segment introduces as ways to avoid harm when gas welding and brazing. Chapter 7: General Welding Safety This closing section shares safety tips that all trade professionals involved in welding should take regardless of the welding process WeldingSafety IG.indd 4 2/2/11 12:32 PM

5 Fast Facts The Occupational Safety and Health Administration (OSHA), of the U.S. Department of Labor, states that welding, cutting, and brazing are hazardous activities posing safety and health risks to more than 500,000 workers in a wide variety of industries. Shielded metal arc welding is a very popular welding process, accounting for over half of all welding in some countries. Spot welding is the most common type of pressure welding. The brightness and danger of the light emitted during welding varies with the type of metal being welded and the welding process utilized. If someone stares at the bright light of any type of electric arc welding machine, serious eye burns can result. If skin is exposed to the radiation energy of a powerful electric arc, it can result in skin burns, premature aging, and ultimately skin cancer. Many cutting and welding processes produce toxic fumes: gases and airborne particulates that can be harmful if inhaled. Lead solder has been banned for consumer use in some countries, as it has been proven to be a highly toxic material that can cause birth defects and serious illness to children and adults. Butane lighters can explode in welders pockets. If molten spatter from welding lands on the plastic lighter, it can instantly melt and penetrate the butane container, causing the butane gas to explode with the force of a small stick of dynamite. Aluminum does not turn red when heating near its melting point WeldingSafety IG.indd 5 2/2/11 12:32 PM

6 Vocabulary Terms acetylene: A colorless, flammable gas used in oxyfuel welding. arc brazing: A brazing process in which the heat is obtained from an electric arc formed between the base metal and an electrode, or between two electrodes. barium: A metallic chemical element that comes from the mineral barite. beryllium: A metallic chemical that is sometimes used as an alloying element with copper and other base metals. brazing: A joining process used to combine dissimilar materials at temperatures lower than welding. cadmium: Cadmium is a metal found naturally in the earth s crust. Pure cadmium is a soft, silver-white metal. It is often used as a coating on steel to prevent rust. cerium: A metal found naturally in the earth s crust. Cerium alloys are used in some types of welding. cobalt: A hard, brittle metallic element, found associated with nickel, silver, lead, copper, and iron ores and resembling nickel and iron in appearance. combustible: A substance that readily ignites and burns. cone: The cone-shaped part of a gas flame next to the opening of the tip. electric arc: The area in which electricity jumps from an electrode to another conductor to produce extreme heat and light. Electric arcs are used in welding. flashback arrestor: A device used in oxy-fuel welding and cutting to stop the flame from burning back. flux: A substance applied to a surface to be joined by welding, soldering, or brazing to facilitate the flowing of solder and prevent formation of oxide. fuse: Turn into liquid by heating. heat sink compound: A white paste made from zinc oxide in a silicone base. inert gas: A non-reactive gas used during chemical synthesis, chemical analysis, or preservation of reactive materials WeldingSafety IG.indd 6 2/2/11 12:32 PM

7 lanthanum: A white soft metallic element that tarnishes readily and occurs in rare earth minerals. manganese: A hard brittle gray polyvalent metallic element that resembles iron but is not magnetic. nickel: A hard malleable ductile silvery metallic element that is resistant to corrosion. oxy-fuel (oxyacetylene): Technology that burns oxygen with gaseous fuel. ozone: A colorless, odorless reactive gas comprised of three oxygen atoms per molecule. particulates: Tiny subdivisions of solid or liquid matter suspended in a gas or liquid. selenium: A non-metallic element used to produce DC current for arc welding. shielding gas: An inert or semi-inert gas used in several welding processes. structural integrity: The ability of the structure to function as designed/required. thorium: A radioactive silvery-white metallic element that can withstand high temperatures. welding electrode: In arc welding, the current-carrying rod or rods used to strike an arc between rod and work. In resistance welding, the component of a machine through which current and pressure are applied to the work. weldment: An assembly with component parts that are joined by welding. Pre-Program Discussion Questions 1. What is welding? 2. Which trade professionals are likely to take on welding tasks? 3. Are there different ways to weld? Explain and describe at least one approach that you know about. 4. What types of dangers might welders experience on the job? 5. If you were a welder, how would you protect yourself from potential injury? WeldingSafety IG.indd 7 2/2/11 12:32 PM

8 Post-Program Discussion Questions 1. What are the main differences among the common types of welding? 2. Is there one type of welding that is more dangerous than others? Explain and discuss. 3. In what ways does OSHA protect welders on the job? Why are these workplace regulations important? 4. Why might trade professionals, even with safety measures, experience harm while welding? 5. How would you promote welding safety in the workplace? Student Projects Welding Safety Training Students work in small groups to create a safety training session for welding professionals. Encourage students to use a variety of techniques (visuals, props, role plays, dramatization, etc.). A Pictorial View of Welding Safety Students review welding safety images found on the Internet and then create posters illustrating and spelling out the safety tips. The posters might be created for workplace safety, a training program, or as a checklist for trade professionals as they gear up for a job. Welding in the Trade Professions Instruct students to research a variety of trade professions that involve welding. Each student selects one profession to research to learn how welding is used in this specific trade, and what steps are taken to guard against welding-related harm. Students write a one-page description, then the class can compile the descriptions to create a vocational handbook on welding safety. Face to Face Students can interview various trade professionals who work as welders or who have welding as part of their work to learn more about welding and welding safety, perhaps for specific types of welding as featured in the film. Students share their interview findings with the class via mixed media, for example, using a visual presentation such as a PowerPoint slide, or an audio recording of the interviewees accompanied by how to charts. Welding Safety Quiz Instruct students to take the online welding safety quiz at (click on Safety Quiz ) to see how much they know about the topic as presented in the film and from their general knowledge. Have them research any topics they are not familiar with. Invite students to create a quiz based on the film topics that trade professionals might take to test their welding safety knowledge WeldingSafety IG.indd 8 2/2/11 12:32 PM

9 Assessment Questions Q1: Which of the following welding types is thought to be the most efficient? a) Arc welding b) Tungsten inert gas welding c) Metal inert gas welding d) Resistance spot welding Q2: Which welding action is used to attach new steel body panels to unibody vehicles during vehicle construction? a) Oxy-fuel welding b) Spot welding c) Plasma arc cutting d) Arc welding Q3: True or False? A 4-shade welding lens is appropriate for levels of light that emanate from an electric welding arc machine. Q4: The has a light sensor that is triggered when a welder strikes an electric arc. Q5: Protecting against welding-generated toxic fumes requires a trade professional to know: a) How base metal coatings interact with welding wires or rods b) The types of coatings on the base metals being welded c) The base metals being welded d) All of the above Q6: Which of the following is not among the types of elements a worker can be exposed to when welding? a) Nickel b) Ozone c) Mercury d) None of the above Q7: Which of the following when mixed with oxyacetylene gas can spontaneously combust? a) Glass b) Petroleum mix c) Molten metal d) Butane gas Q8: True or False? The light from a gas welding flame is potentially as damaging to the eyes as an electric arc. Q9: What is the proper way to light a gas torch? Q10: What happens if a worker does not mark spots to be welded on aluminum? a) The aluminum will turn red but the welder will not know. b) The aluminum will not heat up but the welder will not know. c) The aluminum will approach its melting point but the welder will not know. d) The aluminum will begin to corrode but the welder will not know WeldingSafety IG.indd 9 2/2/11 12:32 PM

10 Assessment Questions Answer Key Q1: Which of the following welding types is thought to be the most efficient? a) Arc welding b) Tungsten inert gas welding c) Metal inert gas welding d) Resistance spot welding A: c Feedback: Metal inert gas welding uses an electric power supply, a small wire electrode, electric current, and inert gas to join metals. Since the welding wire and shielding gas are automatically fed through the nozzle, this is one of the fastest and most efficient welding methods. Q2: Which welding action is used to attach new steel body panels to unibody vehicles during vehicle construction? a) Oxy-fuel welding b) Spot welding c) Plasma arc cutting d) Arc welding A: b Feedback: Spot welding is the most common type of pressure welding. Pressure spot welding is often used to join new steel body panels to unibody vehicles during vehicle construction and sometimes during collision repair. Q3: True or False? A 4-shade welding lens is appropriate for levels of light that emanate from an electric welding arc machine. A: False Feedback: Welding lenses are graded with numbers from 4 for a light shade to 12 for a very dark shade. A 4-shade lens might be used for soldering, which produces very little light. A very dark shade lens of 12 might be needed when welding thick steel plates on a large ship. Q4: The has a light sensor that is triggered when a welder strikes an electric arc. A: Automatic darkening helmet Feedback: Automatic darkening welding helmets are gaining popularity. They allow you to look at the parts to be welded with a very low shade lens with the helmet down over your face. Then, a light sensor on the helmet instantly detects when you first strike an arc and the lens instantly goes to a preset darkness to protect your vision. Small knobs inside the automatic welding helmet allow you to adjust lens darkness and darkening speed WeldingSafety IG.indd 10 2/2/11 12:32 PM

11 Q5: Protecting against welding-generated toxic fumes requires a trade professional to know: a) How base metal coatings interact with welding wires or rods b) The types of coatings on the base metals being welded c) The base metals being welded d) All of the above A: d Feedback: The potentially hazardous materials produced when welding vary. Workers should consider the type of base metals being welded, like iron, steel, aluminum, zinc, and so on. They should also know about any coatings on the base metal, like zinc on steel for rust protection. And then they should determine how they interact with the type welding wire or rod utilized, the type shield gas or flux, and the ingredients in the welding cleaners applied before and after welding. All can contain harmful materials, and when mixed or used together, they can become even more toxic. Q6: Which of the following is not among the types of elements a worker can be exposed to when welding? a) Nickel b) Ozone c) Mercury d) None of the above A: d Feedback: When welding or cutting metals, you can be exposed to arsenic, barium, beryllium, cadmium, cobalt, lead, manganese, mercury, nickel, selenium, and other metals, as well as ozone. Q7: Which of the following when mixed with oxyacetylene gas can spontaneously combust? a) Glass b) Petroleum mix c) Molten metal d) Butane gas A: b Feedback: Welders should not use oil or grease to lubricate metal fittings on welding equipment or on oxyacetylene valves, hoses, and threaded fittings. And, they should keep all crude-based materials away from oxy-welding equipment. When oxyacetylene gas and petroleum mix, they can combust spontaneously WeldingSafety IG.indd 11 2/2/11 12:32 PM

12 Q8: True or False? The light from a gas welding flame is potentially as damaging to the eyes as an electric arc. A: False Feedback: The brightness of the gas welding flame is not as bright as an electric arc. Welding goggles with the correct lens rating are adequate when oxy-gas welding and brazing, as less lens darkness is required. Q9: What is the proper way to light a gas torch? A: 1. Open the acetylene valve 2. Open the oxygen valve 3. Adjust the flame Feedback: When lighting a gas torch, a worker cracks open the acetylene valve first. Once lit, he or she can crack open the oxygen and adjust the flame by slowly turning each valve open or closed as needed to obtain the correct flame desired. If the welder opens the oxygen and then the acetylene, a loud pop or small explosion can result at the tip of the torch. Q10: What happens if a worker does not mark spots to be welded on aluminum? a) The aluminum will turn red but the welder will not know. b) The aluminum will not heat up but the welder will not know. c) The aluminum will approach its melting point but the welder will not know. d) The aluminum will begin to corrode but the welder will not know. A: c Feedback: Aluminum melts at much lower temperatures than steel. Aluminum melts at about 1,200 F. However, aluminum does not turn red when heating near its melting point. A welder rubs a heat crayon on the parts to be welded so he or she can visually monitor how much heat has transferred into the aluminum. The crayon mark will start to melt when the aluminum is near its melting point. This will help avoid burn through or damage to the aluminum parts being welded WeldingSafety IG.indd 12 2/2/11 12:32 PM

13 Additional Resources American Welding Society: Safety & Health Fact Sheets How.com: Welding Safety, Equipment, Tips & Techniques Search on Welding Safety Miller Welding safety books and pamphlets NASD: National Ag Safety Database Search on Welding Safety Oklahoma State University: Environmental Health & Safety Search on Welding Safety United States Department of Labor Occupational Safety and Health Administration Search on Welding Safety Weld Guru Welding Information Center Library & Knowledge Base WeldingSafety IG.indd 13 2/2/11 12:32 PM

14 Additional Video Programs from Films Media Group Available from Films Media Group Introduction to Gas Metal Arc Welding and Flux Core Welding There are similarities between gas metal arc welding and flux core arc welding, including the use of direct current to provide constant voltage. Viewers learn about the different types of electrodes wires used in each outfit. Wire feeders are demonstrated along with the spools that feed them. Students see how to position the electrode and how to establish a good weld pool. Safety practices are clearly demonstrated and explained. A Meridian Production. (11 minutes) 1998 Order # Introduction to Gas Tungsten Arc Welding Gas tungsten arc welding presents special safety concerns. Viewers are warned of the suffocation hazards present when working with inert gases and why good ventilation is required. Electrode leads, hoses, regulators, and collets are demonstrated and explained as well as the use of the post flow timer to protect the weld from contamination. Also discussed are using the correct collet set and electrode size and type needed for the job. A Meridian Production. (11 minutes) 1998 Order # Tools of the Trade: Inside the Welder s Toolbox This program shows viewers the safe way to work with fire, gas, and molten metal as it profiles the tools used by welders to perform a variety of tasks. Specific tools and equipment for OFW, GMAW, GTAW, and SMAW are spotlighted, along with a variety of general tools and safety items. The video also takes a look at basic welding diagrams and pre-welding treatment of materials. A viewable/printable instructor s guide is available online. A Shopware Production. (23 minutes) 2008 Order # Auto Body Repair: Welding This video puts safety first as it explains how to use a MIG (GMAW) welder. Weld types, welder setup, destructive tests, and general welding techniques are covered. The causes of contact burnback, incomplete fusion, and other problems are identified. A viewable/printable instructor s guide is available online. A Shopware Production. (23 minutes) 2005 Order # Written by Michele Israel WeldingSafety IG.indd 14 2/2/11 12:32 PM