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Structural Collapse Technician Training
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Structural Collapse Technician Training

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  1. Structural Collapse Technician Training Appendix C: Metal Burn Cutting Jan09

  2. Unit Objectives • The student will understand the capabilities and limitations of all the types of metal burning that can be used in US&R operations • Understand how to efficiently and safely cut and remove multiple pieces of steel from a debris pile

  3. Enabling Objectives • Discuss how to conduct a site hazard analysis • Select appropriate PPE • Select the most efficient metal burning equipment based on needs of an incident • Discuss safety practices associated with the different metal burning equipment • Identify hazardous situations found when cutting and burning on a debris pile • Understand the safety practices to minimize risk to rescuers.

  4. Enabling Objectives • Discuss the use & setup of the various types of metal burning equipment based on safety, material type & thickness • Identify special issues involved with • Compressed gas cylinders • Oxy / acetylene—use and safety • Gasoline / oxygen operation • Discuss proper breakdown, storage and shipping methods for the metal burning equipment in FEMA US&R Cache

  5. Topics to be discussed • Oxy/Fuel process & Safety • Personal Protective Equipment • Types of Metal Burning Equipment • Oxy/Acetylene • Oxy/Gasoline • Exothermic/Oxygen Lance • Plasma Arc • Storage & shipping methods

  6. Oxy Fuel Process

  7. General Safety Guidelines • Metal burning requires strict compliance with all manufacturer’s safety guidelines • Biggest causes of injury • Burns from hot material or ultraviolet rays • Breathing toxic materials • Wear full PPE at ALL TIMES • Wear UV rated eye protection • Use proper respiratory protection • Work in 2 person teams

  8. General Safety Guidelines (cont.) • Inspect all equipment prior to use for damage and leaks • Have a fire extinguisher or small hose line available for spot fires • Hydrate often • Consider the reaction of your actions before and while cutting a piece of steel or cable

  9. Have a safety person watch the area for fire and other hazards Be aware of heavy equipment and other people working above and below

  10. Two Person Team The tender is the burner’s second set of eyes because the person burning is focused on the progress of the cut

  11. Personal Protective Equipment • In addition to the Std US&R PPE • Shaded eye protection • Leather gauntlet gloves • Respiratory protection ( Organic Vapor) • Consider the PAPR • The level of protection will be dependant on the Situation and type of Metal to be removed

  12. 4 different scenarios requiring PPE selection

  13. Personal Equipment • Crescent wrench • Striker/spare flint • Tool belt • Tip Cleaners • Spare Tips • Marking Paint • Tape Measure • Soapstone

  14. Oxy-Acetylene Most common Oxy-fuel Process

  15. Oxy/Acetylene • Advantages • Commonly used in many industries • Wide variety of accessory equipment • Disadvantages • Has wide flammable limits • Limited by the withdrawal rate of 1/7 per hr

  16. Oxy-Acetylene - Safety Practices • Do not operate Acetylene above 15 PSIG • Do not withdraw more than 1/7 of the cylinder contents per hour • Do not drain all of cylinder contents • Keep components and area clear of grease, oil and other oxidizers/flammables

  17. Oxy-Acetylene - Safety Practices • Always operate with cylinder secured in an upright position • Do not operate without Flashback Arrestors and reverse flow check valves • Always perform a mechanical check for leaking components

  18. A small Leak can create a BIG event This event was caused by a leaking 12 cubic ft. acetylene cylinder similar to what may be carried in your US&R cache

  19. Oxy Acetylene Equipment Acetylene cylinder Must be stored & operated in upright position

  20. Acetylene Cylinder Open cylinder 1 to 1 ½ turns Compressed to a pressure of 200-250 PSIG Unstable in a gas form if above 15 PSIG

  21. Oxygen Cylinder • Compressed to a pressure of 2250 PSIG • Must be secured at all times • Must be capped in an upright position for transport or when not in use

  22. Alternative oxygen sources - Liquid Oxygen • The Dewar can evaporate 4500 Cu. Ft. of gas from a liquid contained in cylinder • External evaporator may be needed • Must be kept in an upright position • The Green compressed cylinder contains about 250 Cu. Ft. of Oxygen

  23. Liquid Oxygen - Dewar

  24. Compressed Oxygen Trailer • Used when a large Demand is needed • A tube style Trailer Cannot be easily moved around a site • May not be readily available

  25. Oxy Acetylene Equipment Acetylene Regulator Oxygen Regulator Do not operate above 15 PSIG • Regulates gas down to its working pressure • Stand off to side when opening cylinder • Regulator screw should be backed out and turn freely before opening cylinder

  26. Flashback Arrestors Flashback Arrestor prevents a fire from burning back to the cylinder Check valves Check valve allows gas to flow in one direction A quick connect acts as a check valve

  27. Hoses are Color CodedAlso threaded differently depending on application • Oxygen is Green with Right-Hand threads • Fuel Gas is Red with Left-Hand threads • All fuel gas equipment has a groove on the fitting to indicate Left-Hand threads

  28. Hoses Get Abused in Debris PileAre exposed to sharp edges, etc.Inspect for cracks/burns & other wear • Make sure hoses are rated for the fuel and proper tip size • Keep clean from grease/oil & other oxidizers

  29. Torches • Various lengths/styles and head angles • Some are made for welding and have a cutting attachment • The size of the tip not the torch length determines the thickness of the cut

  30. Torch Tips

  31. Tip Selection Chart A 145 cu. ft. cylinder should not have a withdrawal rate of more than 21 SCFH Refer to the chart above for safe tip size

  32. Oxy-Gasoline - Petrogen

  33. Oxy-Gasoline - Petrogen • Advantages: • Can cut steel that is up to 14 in. thick • Will cut through various sized air gaps • Less likely to fuse itself back together • Not limited by the fuel cylinder size

  34. Oxy-Gasoline - Petrogen • Disadvantages: • Equipment is not available locally • Rescuers must understand that the Petrogen torch setup, tuning and usage is different than the oxy-acetylene setup • Failing to understand the differences will produce poor cutting results

  35. Petrogen Safety Practices • Always perform a check for leaks • When checking for a fuel leak look for liquid fuel on the ground and couplings • Secure fuel tank in the upright position Fuel cannot flow with tank on its side

  36. Petrogen Safety Practices • A flashback arrestor should be used on the oxygen line. • One is not required for the fuel line • Do not operate fuel tank below 10 psi

  37. Petrogen Equipment Fuel Tank • Holds 2.5 gallons of fuel • Equal to a 250 cu.ft. acetylene cylinder • Has a pressure relief on the filler cap • Has a safety valve on the pressure gauge & fuel valve • Use the freshest fuel available

  38. Petrogen Equipment - Torches • Various lengths/styles and head angles • The size of the tip not the torch length determines the thickness of the cut

  39. Petrogen Equipment Torch Tips • Tip has two pieces • Fuel enters the tip as a mist /atomized gasoline oxygen mixture • Has oxygen and pre heat ports similar to Oxy-Acetylene • If tuned properly, fuel entering tip should keep tip cool as it vaporizes

  40. Petrogen Equipment Tip Chart • Serves as a basic starting point • Settings will depend on operator experience • You are not limited by the 1/7 per hour rule • Tip does not need to be as clean a for oxy-acetylene tip

  41. Petrogen Equipment A big advantage of the Petrogen is that is can be fully broken down and repaired in field with a spare parts kit.

  42. Petrogen Equipment - Poor Practice • Operator Error caused this overheated equipment • Typically caused by too close of a coupling distance or tuning the torch too lean • A coupling distance of ½” is a good safe starting point Heat transferred from Tip & overheated mixer

  43. Exothermic Torch Exothermic uses a consumable rod with oxygen pushing through the rod. Its primary Function is to melt the material

  44. Exothermic Torch • Advantages • Can burn through almost anything • Disadvantages: • Operator must wear full PPE • Large spark showers of molten metal • Area of work must be free of combustibles

  45. Oxygen Lance • Uses exothermic technology but uses a much thicker and longer consumable rod • This allows the operator to be at a safer distance away from the material being cut

  46. Plasma Arc - Electric arc & Compressed air • Advantages • Can cut ferrous & non ferrous metal • Burns clean • Low slag & sparks • Disadvantages: • Systems that can burn thicker material are large + heavy • Also require 220v to operate

  47. Basic Torch Handling Skills • Make yourself as comfortable as possible • Try to work the torch like a pool cue or pivot using your hand or material/debris as a pivot point

  48. Estimating Steel Weight - Area Method 12” 12” • Steel weighs 490 lbs per cubic ft • Steel 1” thick weighs 490pcf / 12” = 40.8 psf • For steel weight per square foot use: • 1” thick Use 40 lbs • ¾” Use 30 lbs • ½” Use 20 lbs • ¼” Use 10 lbs 12” 12” 1” 12”

  49. Area Method Examples 1 & 2 36”x 2” Example 1 12”x 2” 36”x 2” Example2 Flanges = 24”x 5” Web = 12”x 3.5 inches

  50. Area Method Example - 1 • What is weight of this 36ft long steel section? • 2” Steel = 2 x 40 psf = 80 psf • Area per ft = 2 x 3 sq ft + 2 x 1 sq ft = 8 sq ft • Weight per ft = 8 x 80 = 640 plf • Total weight = 640 x 36 = 23,040 lbs • Exact weight = 652.8 plf (only 2% off) Pl 36" x 2" Pl 12" x 2" ea end Pl 36" x 2"