Hot work training - Welding and cutting based on IOGP

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1. Hot work training – Welding and Cutting CSSS & IOGP RP

2. Content Potential Hazards Welding Operations Safe Welding Operating Procedures Personal Protective Equipment Cutting Operations Gas Cylinder Storage Safe Operating Procedure - Cutting Hot Work

3. WELDING & CUTTING The term “Arc Welding" refers to all types of welding that require a source of electrical current to operate. “Cutting” refers to an operation involving the used of compressed oxygen-acetylene equipment.

4. Fires caused by flying sparks or molten metal. Electrocution from faulty equipment and wet body. (Welding Operation Only) Contact with extreme heat, or burns from sparks, slag, hot and molten metal. Occupational ill health from ultra violate radiation and smokes emitted from welding and cutting operation. Explosion or Flash fires Potential hazards

5. WELDING Equipment Inspections: Inspect welding cables & grounding / earthing straps for broken or damaged insulation. Electrode holders for broken insulators or worn holders. Do not use equipment that is wet. Do not use wet gloves or bare hands to change electrodes.

6. WELDING

7. WELDING A Hot Work permit has been raised The surrounding area has been Inspected & Checked All combustible & Flammable materials have been removed. All welding equipment and accessories, have been inspected and checked Note: Electrical equipment will only be repaired or serviced by qualified electricians. Safe Welding Operations require that:

8. WELDING

9. WELDING Inspect & check Fire Extinguishers are in place. All Tripping Hazards ie . trailing cables have been removed. Fire Watcher is on stand-by. Appropriate PPE is being used. Welding Screen is in position to protect other workers from the ultra violet rays. Equipment has been inspected & certified Safe Welding Operations require that: (cont’d..)

10. WELDING Welding equipment will be inspected to ensure that The following, are in a good working condition: Grounding / Earthing strap Earth leakage circuit breaker. Electrical and welding cables. Electrode holder

11. WELDING

12. WELDING & CUTTING Welding, cutting, or other hot work shall never be performed on drums, barrels, tanks, or any containers until they have been cleaned thoroughly to ensure that there are no flammable vapors present. When left unattended, welding machines will be switched off and electrodes removed from their holders

13. PPE Fire resistant gloves Fire resistant clothing protect from sparks and hot metal. Safety Shoes Full face protection with filtered lens. (Welding Helmet)

14. Eye/face Protection Choose a helmet that fits tightly so that light can not enter or be reflected into the helmet Wear helmet correctly, do not hold in the hand Use correct filter lens, replace if scratched or damaged When removing/grinding slag from welds, eye face protection is required as well other PPE

15. WELDING

16. PPE Wear the correct clothing to protect from UV radiation, hot metal, sparks and slag Keep clothing clean of oil and grease Use only approved welding gloves Do not wear rings or jewelry Do not wear synthetic clothing, this fabric can burn/melt

17. WELDING Workers performing arc welding operations with the correct PPE.

18. An oxyacetylene welding / cutting unit is made up of: Cylinders of oxygen and acetylene, Regulators, Hose, fitted with flash back arrestors and non return valves Torch.

19. Cutting

20. Cutting Flash Back Arrestor to prevent back flow

21. Oxyacetylene Welding Equipment

22. Oxyacetylene Welding Equipment

23. Cutting Oxyacetylene Cylinders’ Safety

24. Cutting Oxyacetylene Cylinders’ Safety (Label)

25. Cutting Missile Effect of falling Cylinders

26. Cutting Oxygen cylinder was blown through block cavity wall. Remains of acetylene cylinder Cylinders involved in fires

27. Cutting

28. Cutting

29. Cylinder storage Cylinders should not be stored in passages, Storage outdoors should be provided to protect the cylinders bottom from corrosion and from direct sunshine. Protection against mechanical shocks and heavy falling objects should be provided. Storage indoors should be above ground, well ventilated, far from heat sources and in a fire resistant construction,

30. Cylinder storage

31. Cylinder storage Cylinders should be placed in an upright not horizontal position. The caps protecting the isolation valve should stay in place during all times of storage, transportation and movement. Post “NO SMOKING” signs Oxygen & fuel gas cylinders should be separated by at least 20’ (6 meters,) or at 5 feet by a wall 1.5 meter high with a half hour rated fire barrier.

32. Cutting

33. Always transport cylinders with valve caps in place & secured Cutting

34. Cylinder laying in a horizontal position. Electrical cord in Contact with the cylinder Cutting

35. Cutting

36. Cutting Safe Work Practices for Cutting Operations Hot Work Permit Inspect & Check the surrounding area Remove all combustible materials from the area & protect all plant equipment and cables Inspect and check, cutting tools and its accessories. Flashback arrestor and non-return valves should be fitted to Gauge outlet and the Torch end of each hose

37. Cutting Inspect & Check Fire Extinguisher Eliminate Tripping Hazards and trailing hoses . Hoses will not be laid near to electrical or welding cable. Fire Watchmen Use appropriate PPE Routine Inspection including leak test to be performed by user. Safe Work Practices for Cutting Operations

38. Cutting Safe Work Practices for Cutting Operations When in doubt, check and confirm with Supervisors before commencing cutting operations Cylinders is properly placed and secured in an approved trolley. Use only a spark/flint gun for the ignition of a gas cutting torch ( not lighters or matches) Valve protection cap must be replaced when cylinder is not in use Oil and grease will be kept away from cutting tools and cylinders

39. Cutting tools Parts and accessories to be inspected are: Compressed gas cylinders. Valves and gauges. Flashback arrestors & NRV Hoses. Cutting torch.

40. Hot Work Remember! All Hot Work Requires: HOT WORK PERMIT 100% CONTAINMENT OF SPARKS & SLAG FIRE WATCH INSPECTION OF ALL EQUIPMENT

41. Picture with FLASH ARRESTER, safety for flash back to cylinder

42. General Safety Tips Never allow oxygen to contact oil, grease or other flammable substances Use the proper regulator for each specific gas Keep regulators free of oil, grease and other flammable substances Check valves stop reverse gas flow, they do not act as a fire stop Always keep cylinders in an upright position Never stand in front or behind a regulator when opening the cylinder valve Always make sure area is safe and flammable free

43. Always wear protective clothing Use proper eye protection If flashback occurs, immediately turn off the O2, then the acetylene, and allow unit to cool Always work in a well ventilated area Always light the acetylene first Use an approved striker, never use matches or cigarette lighter General Safety Tips

44. Oxyacetylene Welding (OAW) The oxyacetylene welding process uses a combination of oxygen and acetylene gas to provide a high temperature flame. OAW is a manual process in which the welder must personally control the the torch movement and filler rod application The term oxyfuel gas welding outfit refers to all the equipment needed to weld. Cylinders contain oxygen and acetylene gas at extremely high pressure.

45. Typical Oxyacetylene Welding (OAW) Station

46. Oxygen Cylinders Oxygen is stored within cylinders of various sizes and pressures ranging from 2000- 2640 PSI. (Pounds Per square inch) Oxygen cylinders are forged from solid armor plate steel. No part of the cylinder may be less than 1/4” thick. Cylinders are then tested to over 3,300 PSI using a (NDE) hydrostatic pressure test.

47. Cylinders are regularly re-tested using hydrostatic (NDE) while in service Cylinders are regularly chemically cleaned and annealed to relieve “jobsite” stresses created by handling .

48. Cylinder Transportation Never transport cylinders without the safety caps in place Never transport with the regulators in place Never allow bottles to stand freely. Always chain them to a secure cart or some other object that cannot be toppled easily.

49. Oxygen cylinders incorporate a thin metal “pressure safety disk” made from stainless steel and are designed to rupture prior to the cylinder becoming damaged by pressure. The cylinder valve should always be handled carefully

50. Pressure Regulators for Cylinders Reduce high storage cylinder pressure to lower working pressure. Most regulators have a gauge for cylinder pressure and working pressure.

51. Regulators are shut off when the adjusting screw is turn out completely. Regulators maintain a constant torch pressure although cylinder pressure may vary Regulator diaphragms are made of stainless steel Pressure Regulators for Cylinders

52. Gas entering the gauge fills a Bourdon tube As pressure in the semicircular end increases it causes the free end of the tube to move outward. This movement is transmitted through to a curved rack which engages a pinion gear on the pointer shaft ultimately showing pressure. Pressure Regulators Gauges Using a “Bourdon” movement

53. Regulator Hoses Hoses are are fabricated from rubber Oxygen hoses are green in color and have right hand thread. Acetylene hoses are red in color with left hand thread. Left hand threads can be identified by a grove in the body of the nut and it may have “ACET” stamped on it

54. Check Valves & Flashback Arrestors Check valves allow gas flow in one direction only Flashback arrestors are designed to eliminate the possibility of an explosion at the cylinder. Combination Check/ Flashback Valves can be placed at the torch or regulator.

55. Acetylene Gas Virtually all the acetylene distributed for welding and cutting use is created by allowing calcium carbide (a man made product) to react with water. The nice thing about the calcium carbide method of producing acetylene is that it can be done on almost any scale desired. Placed in tightly-sealed cans, calcium carbide keeps indefinitely. For years, miners’ lamps produced acetylene by adding water, a drop at a time, to lumps of carbide. Before acetylene in cylinders became available in almost every community of appreciable size produced their own gas from calcium carbide.

56. Acetylene is stored in cylinders specially designed for this purpose only. Acetylene is extremely unstable in its pure form at pressure above 15 PSI (Pounds per Square Inch) Acetone is also present within the cylinder to stabilize the acetylene. Acetylene cylinders should always be stored in the upright position to prevent the acetone form escaping thus causing the acetylene to become unstable. Acetylene Cylinders

57. Acetylene Cylinders Cylinders are filled with a very porous substance “monolithic filler” to help prevent large pockets of pure acetylene form forming Cylinders have safety (Fuse) plugs in the top and bottom designed to melt at 212° F (100 °C)

58. Acetylene Valves Acetylene cylinder shut off valves should only be opened 1/4 to 1/2 turn This will allow the cylinder to be closed quickly in case of fire. Cylinder valve wrenches should be left in place on cylinders that do not have a hand wheel.

59. Regulator pressure may vary with different torch styles and tip sizes. PSI (pounds per square inch) is sometimes shown as PSIG (pounds per square inch -gauge) Common gauge settings for cutting 1/4” material Oxy 30-35psi Acet 3-9 psi 1/2” material Oxy 55-85psi Acet 6-12 psi 1” material Oxy 110-160psi Acet 7-15 psi Check the torch manufactures data for optimum pressure settings Oxygen and Acetylene Regulator Pressure Settings

60. Regulator Pressure Settings The maximum safe working pressure for acetylene is 15 PSI !

61. Typical torch styles A small welding torch, with throttle valves located at the front end of the handle. Ideally suited to sheet metal welding. Can be fitted with cutting attachment in place of the welding head shown. Welding torches of this general design are by far the most widely used. They will handle any oxyacetylene welding job, can be fitted with multiflame (Rosebud) heads for heating applications, and accommodate cutting attachments that will cut steel 6 in. thick. A full-size oxygen cutting torch which has all valves located in its rear body. Another style of cutting torch, with oxygen valves located at the front end of its handle.

62. Verify that equipment visually appears safe IE: Hose condition, visibility of gauges Clean torch orifices with a “tip cleaners” (a small wire gauge file set used to clean slag and dirt form the torch tip) Crack (or open) cylinder valves slightly allowing pressure to enter the regulators slowly Opening the cylinder valve quickly will “Slam” the regulator and will cause failure. Typical startup procedures

63. Never stand directly in the path of a regulator when opening the cylinder Check for leaks using by listening for “Hissing” or by using a soapy “Bubble” solution Adjust the regulators to the correct operating pressure Slightly open and close the Oxygen and Acetylene valves at the torch head to purge any atmosphere from the system. Typical startup procedures

64. Always use a flint and steel spark lighter to light the oxygen acetylene flame. Never use a butane lighter to light the flame Typical startup procedures

65. There are three distinct types of oxy-acetylene flames, usually termed: Neutral Carburizing (or “excess acetylene”) Oxidizing (or “excess oxygen” ) The type of flame produced depends upon the ratio of oxygen to acetylene in the gas mixture which leaves the torch tip. Flame settings

66. Pure Acetylene and Carburizing Flame profiles

67. Neutral and Oxidizing Flame Profiles

68. The neutral flame (Fig. 4-1) is produced when the ratio of oxygen to acetylene, in the mixture leaving the torch, is almost exactly one-to-one. It’s termed ”neutral” because it will usually have no chemical effect on the metal being welded. It will not oxidize the weld metal; it will not cause an increase in the carbon content of the weld metal. The excess acetylene flame (Fig. 4-2), as its name implies, is created when the proportion of acetylene in the mixture is higher than that required to produce the neutral flame. Used on steel, it will cause an increase in the carbon content of the weld metal. The oxidizing flame (Fig. 4-3) results from burning a mixture which contains more oxygen than required for a neutral flame. It will oxidize or ”burn” some of the metal being welded. Flame definition

69. C.1. A Job Hazard Assessment is completed and controls identified when carrying out task specific Field Level Hazard Assessments. C.2. Work in live plant is limited only to hot works that cannot be conducted in a safe, no-hot-work area. C.3. A competent fire watch is assigned throughout the hot work activity. The fire watch stays on site during short breaks and waits until the work party confirms the job is sufficiently cool before leaving the worksite. C.4. Functional, calibrated personal or stationary atmospheric monitors are available to constantly monitor the level of combustible gases. C.5. An authorised person (fire watch) periodically verifies and documents that the continuous air quality testing is being done before and during hot work. C.6. A Hot Work Permit from an authorised person has been obtained before any welding, grinding or oxy-gas cutting is done in a classified area and around equipment that could contain flammable materials. C.7. Persons who do atmosphere tests and the Fire Watch have received approved training in both areas and have unique identification (e.g. fluorescent vest) to indicate their presence. C.8. Fire protection and spark containment for hot work (every activity point/vicinity) is in place. C.9. Competencies of employees required to carry out hot works have been verified. C.10. Adequate grounding to welding sets is provided. Cables and hoses are inspected daily by users and are not damaged. CSSS provisions