Oxy-Fuel Safety Training. Participant s Guide

Transcription

1 Oxy-Fuel Safety Training Page 1 of 19

2 Contents What s Included?... 3 Oxy-Fuel Safety Training Objectives... 4 Chapter 1: Safety & Responsibility... 6 Chapter 2: Gases in the Work Area... 7 Chapter 3: Equipment Set-up: Regulators & Hoses... 9 Chapter 4: Torches & Safety Chapter 5: Lighting the Torch & Adjusting the Flame Chapter 6: Cutting Advice Chapter 7: Review & Conclusion Page 2 of 19

3 What s Included? In this guide you will find the following items: Worksheets Chapter review questions Key Points to Takeaway Oxy-Fuel System Set-Up and Shut-Down Procedure Checklist Two versions for both acetylene and alternate fuels: o Detailed checklist: all required steps listed (novice) o Quick step checklist: high-level quick reference (expert) Helpful Resources / Handouts Proper Shaded Lens (ANSI Z49.1) UN Specifications For Commonly Used Gases Regulator Designated Service (ASNI Z49.1, Section ) Hose Grades (RMA IP-7 CGA E-1 R/RM/T) Victor Tip Charts Common Oxy-Fuel Industry Terms Page 3 of 19

4 Oxy-Fuel Safety Training Objectives Upon completion of this course, students will be able to demonstrate their knowledge of the safe and proper use of oxy-fuel equipment by: Answering 20 assessment questions accurately Performing the appropriate step-by-step safety procedures required from set-up to shut-down of oxy-fuel system. Page 4 of 19

5 Chapter Review Worksheets Page 5 of 19

6 Chapter 1: Safety & Responsibility 1. The foundation for all oxy-fuel processes is the Triangle of Combustion. What are its three elements? 2. What can you do to control these three elements during oxy-fuel processes? 3. In the video, Tim shows his acetylene cylinder as being green. Since a cylinder s color cannot be used to identify the contents of the cylinder, how does he know that his cylinder contained acetylene? 4. List the things you can do to prevent a cylinder from becoming a projectile. Key Points to Takeaway: Safety is everyone s responsibility. Remember the safety fundamentals from good housekeeping to wearing the appropriate PPE. Cylinder identification is not determined by the color. Careless handling can turn a cylinder into a projectile safely handle with care. Page 6 of 19

7 Chapter 2: Gases in the Work Area 1. Besides being available in a high pressure compressed gas cylinder, what other types of containers is oxygen available? 2. Whether you have a cylinder of oxygen or it is running through a pipeline, why should it never be used to blow dust off your clothing or for ventilation? 3. Of the fuel gases discussed in this chapter of the video, acetylene has some very important safety considerations because of its unstable and volatile nature. below. Fill in the blanks a. Use and store the cylinder in the position. b. Never use acetylene above PSI (Pounds per Square Inch). c. You can only withdraw of the cylinder s volume/content per hour. 4. Calculate how many usable cubic feet of acetylene you can safely withdraw per hour for the following cylinder contents. 350 cu. ft. cylinder 210 cu. ft. cylinder Page 7 of 19

8 5. What could happen if the safety considerations listed above are not adhered to? Let s start with the maximum delivery pressure (PSI). 6. List the three common alternate fuels used in oxy-fuel processes that were mentioned in the video. 7. What characteristics does each of these alternate fuels have? Key Points to Takeaway: Oxygen should NEVER be used in place of air. Fuel gases most commonly used in oxy-fuel processes are acetylene and LP (Liquefied Petroleum). Because of its nature, acetylene has several safety considerations that should be adhered to at all times for proper handling and usage. Alternate fuels do not have the same limitations as acetylene. Page 8 of 19

9 Chapter 3: Equipment Set-up: Regulators & Hoses 1. Using the Helpful Resource Regulator Designated Service (ASNI Z49.1, Section ) referred to in the video, find the statement that was made regarding proper gas usage for pressure regulators. What is that statement supported by the AWS as a safety standard and why should it not be ignored? 2. Explain why the gauges on a regulator are marked with Use No Oil. 3. Both the cylinders and regulators require safety inspections prior to installing the regulators to the cylinders. What should you be looking for? a. That all inlet valves, threads and seats are free from oil and dirt. b. That all outlet valves, threads and seats are free from oil and dirt. c. That the fittings are not dinged up or damaged in any way. d. All of the above. 4. What does it mean to crack the cylinder? Explain how this is to be done properly. Page 9 of 19

10 5. Are all gas hoses the same? Explain. 6. Why is it important to purge the gas hoses before using? 7. Fill in the blanks. Once the regulators have been installed, the cylinder valves must be opened safely. The adjusting knobs on both should be backed out. Then, starting with oxygen, stand to the side and open the cylinder valve. Once stabilized, the valve needs to be opened up. On the acetylene valve, stand and open it slowly, but only about to no more than. Alternate fuels should also be opened. Key Points to Takeaway: A regulator is to be used with the gas and pressures for which it is designed. Inspection of all fittings and connections should become a habit before assembling oxy-fuel equipment each and every time. Always make sure that they are free from oil, grease and dirt. Crack the cylinder valves before installing the regulator, every time. Stand with cylinder valve between you and the regulator when slowing opening the cylinder valve to its proper position based on the type of gas. The hoses should always be purged prior to installing the torch to remove contaminants. Page 10 of 19

11 Chapter 4: Torches & Safety 1. Each of the hazardous conditions defined in the video are listed below. Think about the causes and what can be done to prevent each from happening. Take into consideration the safety devices that help to prevent conditions like these from occurring; without them, there could be an explosion within the system thus ultimately leading to injury or worse. Use the spaces provided to write your responses. a. Reverse flow of gases when oxygen enters the fuel gas side of the system or fuel gas enters the oxygen side due to a restriction of one of the gases or an imbalance of pressure. Cause: Prevention: b. Flashback the return of a flame through the torch, into the hose and even into the regulator. Cause: Prevention: Page 11 of 19

12 c. Backfire the return of a flame back into the torch which produces a popping sound, and the flame either extinguishes itself or reignites at the tip. Cause: Prevention: d. Sustained backfire when a backfire occurs and continues burning in the torch. It may have a popping sound followed by a continuous whistling or hissing sound Cause: Prevention: 2. Selecting the correct nozzle and tip is critical to any oxy-fuel process. The determining factors discussed in the video pertain to the thickness of the plate and the type of gas being used. If you have a job to cut a 2 plate with acetylene gas, you will need to know the proper size cutting tip to use as well as the recommended pressure settings for that size tip. Use your Victor tip charts to determine this information and note your answers below. a. Cutting tip size: b. Cutting oxygen pressure setting: c. Preheat acetylene pressure setting: Page 12 of 19

13 3. The statement is made in the video about using the right tool for the job. This is very important when assembling a torch. Think about when a wrench is required to attach certain components, and when it should not be used on other torch components. Use the spaces provided to write your responses. 4. O-rings play a vital role in the structure of a torch, which is why it is important to inspect the cone-end of the heating or a cutting attachment prior to assembling the torch. Provide the correct answers to the following questions. a. What can happen if the o-rings are damaged or missing on either of these attachments? b. What should be done? 5. Prior to assembling your oxy-fuel torch, you should inspect the torch thoroughly for damaged or missing parts and to ensure that it is free from oil, grease and slag or other tip obstructions. Once the torch has been inspected and assembled, there are two other critical steps that need to be performed prior to lighting the torch: a leak check and purging the torch. Use your checklist to review these steps and answer the questions below. Page 13 of 19

14 a. Leak Check: What would indicate a leak in the high pressure side of the system? If no leak is detected in either of the high pressure sides of the system, the oxygen pressure should be set at PSI and the fuel pressure should be set at PSI. After closing both cylinder valves and turning the adjusting mechanism counterclockwise ½ turn, how will you know that the system is leak tight? What should be done if there is movement of the needles on the gauges once the cylinder valves are opened again? b. Purging a cutting torch: Starting with the oxygen side, in addition to opening the oxygen valve and adjusting the regulator to the required delivery range, what else should be done to purge the oxygen hose? Page 14 of 19

15 6. After following the purging of the fuel side by opening the fuel valve on the torch handle for 3 to 5 seconds, what is the last thing that should be checked and reset, if necessary? Key Points to Takeaway: Understand the hazards associated with using oxy-fuel equipment, what causes the hazards to occur and the safety devices designed to prevent them. The best rule of thumb is to have safety devices as close to operation as possible. If not using a Victor torch with built-in check valves and flashback arrestors, accessory safety devices should be added at the torch. Always inspect your torch prior to each use. Check for damage to valves, fittings and seating areas, make sure o-rings are intact and in place, ensure the torch is free from oil and grease and that tips are free from slag or obstructions. Use the manufacturer s tip charts for proper nozzle and tip selection. Once the torch is assembled, perform a leak check of the entire system and purge the torch to eliminate the possibility of gases mixing prematurely. This could lead to a flashback, or worse.. Page 15 of 19

16 Chapter 5: Lighting the Torch & Adjusting the Flame 1. Draw a line to indicate which valve is turned on first when lighting the torch. 2. Draw a line to indicate which valve is turned off first when shutting the torch down. 3. By shutting the torch down in this order, what are you checking each time you use the torch? 4. When using a combination torch for cutting, the oxygen valve on the handle should be opened all the way, and then the oxygen valve on the cutting attachment is used to adjust the flame. By doing so, you are making sure you are supplying maximum to the cutting lever. 5. Describe how to achieve a neutral flame. 6. Because alternate fuels tend to float, there are three different techniques shown in the video. Which technique would work best in windy conditions? Page 16 of 19

17 7. When shutting down the entire oxy-fuel system, there is a proper sequence to doing so. Each step in the sequence is listed below, but not in the correct order. Number the steps to indicate the correct order in which they should be performed. Release the pressure inside the system by first opening the oxygen valve on the torch until the pressure is down and then the fuel gas valve on the torch. Wait a few minutes and check inlet gauge to ensure no pressure remains in the system. Close both cylinder valves Release the tension on the regulator adjusting screws by turning counterclockwise until they move freely 8. Both valves on the torch should not be opened at the same time when bleeding the pressure from the system during shut-down. Explain why and what might happen? Key Points to Takeaway: Torch lighting differs somewhat between acetylene and alternate fuel, but regardless of which gas you are using, always purge the torch before lighting it. Always follow the proper sequence in opening the torch valves when lighting the torch and closing the valves when shutting down the torch. Keep this shut-down sequence acronym in mind: OFFL = Oxygen First, Fuel Last. Shut down the entire system using the appropriate steps and never leave a pressurized oxy-fuel system unattended. Page 17 of 19

18 Chapter 6: Cutting Advice 1. What should you do before you light your torch? (Think of the old saying, Measure twice, cut once. ) 2. Fill in the blanks. The torch tip should be held approximately of an inch to a of an inch from the base material. This puts the inner cones of the flame the correct distance from the base material for a good quality cut. 3. What does Ken mean when he says he will be patient as the material heats up to a cherry-red color before he begins? 4. Explain the proper way to shut down the torch. Key Points to Takeaway: Get comfortable with the torch in your hands and make a couple of practice runs before lighting. Maintain the proper flame distance from the work piece and the correct cut speed for achieving a quality cut. Remember the proper torch shut-off: OFFL (Oxygen First, Fuel Last) Page 18 of 19

19 Chapter 7: Review & Conclusion Fill in each blank: Safety is responsibility. The Triangle of is the basis for all oxy-fuel processes. Use the PPE for the job at hand. Good is critical to a safe working environment. Only use gases for which they are intended is NOT air! Secure all, handle them with care and keep them away from sparks and heat. Remember 1/7 th rule, maximum safe working pressure and upright storage rule. all equipment to ensure it is all in proper working condition, free of oil and grease. Understand backfire and and how to prevent the conditions by proper use of the equipment and by using check and flashback arrestors. Refer to manufacturer s operations instructions for proper set up, and flow requirements for the equipment being used. Always the system and check for before lighting. Use proper procedures. Always have your equipment serviced and repaired by a technician. Page 19 of 19