AWS-CERTIFIED WELDING INSPECTOR : PART-5

CERTIFIED WELDING INSPECTOR

PART-5

CHAPTER 2...Continues...

SAFE PRACTICES FOR WELDING INSPECTORS

Notes:

26. The different types of ventilation are
Natural
General area mechanical ventilation
Overhead exhaust hoods
Portable local exhaust devices
Downdraft tables
Crossdraft tables
Extractors built into the welding equipment
Air ventilated helmets

27. Lighting inside the Work area should be low voltage,  12V. If 110V is used, GFCI to be used.

28. GFCI: Ground-Fault Circuit-Interrupter

29. A "Standby" Person is needed outside the confined space, if work is being executed inside the confined space.

30. Adequate oxygen for life support : At least 19.5%by volume

31. If O2 is more than 23.5% by volume it is called a oxygen rich atmosphere.

32. Heavier than air gases: Argon, CO2, Propane, methylacetylene- propadiene.

33. Lighter than air gases: He, H2.

34. Certain materials are toxic which are having a maximum exposure limit of 1.0mg/m3.

35. Toxic materials are Antimony, Arsenic, Barium, Beryllium, Cadmium, Chromium, Cobalt, Copper, Lead, Manganese, Mercury, Nickel, Selenium, Silver and Vanadium.

36. DOT: Department of Transportation

37. Adiabatic recompression can occur, if the valves are opened rapidly.

38. In oxygen, cylinder adiabatic recompression can cause heat, which can ignite the valve seat, which may cause the metal to melt or burn.

39. The valves of compressed gas cylinders should be opened momentarily and closed immediately. This is known as “cracking the cylinder valve”.

40. Flammable gas cylinders typically have a left-hand thread while nonflammable gas cylinders have a right –hand thread.

41. It is advisable to return cylinders to the supplier with about 25psi of contents remaining. This prevents possible contamination by the atmosphere during shipment.

42. Piping and fittings for acetylene and methylacetylenepropadiene (MPS) manifolds must not be unalloyed copper or alloys containing 70% or more copper. These gases react with copper under certain conditions to form unstable copper acetylide.

43. Acetylene should never be used at pressure over 15psi [103kPa)

44. Acetylene and methylacetylenepropadiene (MPS) never be used in contact with Silver, Mercury or alloys containing 70% or more copper.

45. Shock currents above 6mA are considered Primary Shock Currents

46. 0.5mA to 6mA are considered secondary shock currents.

47. The 0.5mA level is called the perception threshold.

48. Lock, tag and try: The phrase noting the physical locking-out of equipment, tagging it for identification and trying the equipment to make sure it is not operable prior to beginning any repair work.

---END OF CHAPTER 2---

These are the important points of this chapter. This blog will be updated time to time to add or delete points depends on their importance felt to the author.

This is not an official blog of AWS. The recommended reading materials as per BOK are to be read throughly before taking the exam. The exam pattern and other details to be confirmed from AWS before taking the exam.

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