WCL Safety Standards & Regulations 3 — Questions and Answers
Question 1: What shade number is recommended by ANSI Z49.1 for the filter lens when using shielded metal arc welding (SMAW) at 200–250 amps?
- Shade 12 (Correct answer)
- Shade 8
- Shade 10
- Shade 14
Correct answer: Shade 12
ANSI Z49.1 recommends shade 12 for SMAW operations in the 200–250 amp range.
Question 2: Which class of fire extinguisher is most appropriate for an electrical fire that ignites near welding equipment?
- Class C (Correct answer)
- Class A
- Class B
- Class D
Correct answer: Class C
Class C extinguishers use non-conductive agents suitable for energized electrical equipment fires.
Question 3: Under Cal/OSHA, when must a confined space entry permit be obtained before a welder enters a tank to perform repairs?
- When the space has any potential for hazardous atmosphere, engulfment, or entrapment (Correct answer)
- Only when the tank previously held flammable liquids
- Only when the tank diameter is less than 4 feet
- When the welder will be inside for more than 1 hour
Correct answer: When the space has any potential for hazardous atmosphere, engulfment, or entrapment
A permit-required confined space entry permit is mandated whenever any of the three hazard conditions (hazardous atmosphere, engulfment, or entrapment) may exist.
Question 4: Which personal protective equipment (PPE) is specifically required to protect against UV and IR radiation produced by the welding arc?
- Welding helmet with appropriate filter lens (Correct answer)
- Standard safety glasses with side shields
- Chemical splash goggles
- Clear face shield only
Correct answer: Welding helmet with appropriate filter lens
A welding helmet with an appropriate shade filter lens is required to block both UV and IR radiation from the arc.
Question 5: What is the primary purpose of the ventilation requirement in AWS D1.1 for welding in enclosed spaces?
- To dilute and remove welding fumes and shielding gases below hazardous levels (Correct answer)
- To cool the weld puddle faster
- To prevent electrode stick
- To maintain ambient temperature below 90°F
Correct answer: To dilute and remove welding fumes and shielding gases below hazardous levels
Ventilation in enclosed spaces is required to dilute welding fumes and prevent oxygen displacement to safe levels for workers.
Question 6: According to OSHA 1910.253, oxygen cylinders in storage must be separated from fuel-gas cylinders or combustible materials by at least what distance or barrier?
- 20 feet or a fire-resistant barrier at least 5 feet high with a 0.5-hour fire rating (Correct answer)
- 10 feet or a fire-resistant barrier at least 3 feet high
- 5 feet or any solid partition
- 50 feet with no barrier alternative
Correct answer: 20 feet or a fire-resistant barrier at least 5 feet high with a 0.5-hour fire rating
OSHA 1910.253 requires oxygen cylinders be stored at least 20 feet from fuel-gas cylinders or combustibles, or separated by a 5-foot-high barrier rated at least 0.5 hours fire resistance.
Question 7: A welder working outdoors in Los Angeles must wear which type of hearing protection when grinding metal between weld passes at noise levels above 85 dBA?
- Earplugs or earmuffs with sufficient noise reduction rating (NRR) (Correct answer)
- No hearing protection is required outdoors
- Double hearing protection (earplugs AND earmuffs) always
- Cotton wool inserted into the ear canals
Correct answer: Earplugs or earmuffs with sufficient noise reduction rating (NRR)
OSHA's hearing conservation standard requires hearing protection when noise exposure reaches or exceeds 85 dBA as an 8-hour TWA.
WCL Safety Standards & Regulations 3
What shade number is recommended by ANSI Z49.1 for the filter lens when using shielded metal arc welding (SMAW) at 200–250 amps?