WCL Safety Standards & Regulations 4 — Questions and Answers
Question 1: What hazard is created when welding is performed near degreasing solvents or chlorinated hydrocarbons such as trichloroethylene?
- Phosgene gas formation from UV arc decomposition of the solvent (Correct answer)
- Increased spatter due to vapor contamination
- Reduced weld penetration
- Electrode coating damage
Correct answer: Phosgene gas formation from UV arc decomposition of the solvent
UV radiation from the welding arc can decompose chlorinated solvents into phosgene, a highly toxic gas.
Question 2: Under Los Angeles city fire code, a hot work permit for welding inside a building must be posted where during the work?
- At the worksite, visible to workers and inspectors (Correct answer)
- At the building entrance only
- In the contractor's office on-site
- Filed with the fire department prior to work only
Correct answer: At the worksite, visible to workers and inspectors
Hot work permits must be posted at the actual work location so all workers and fire inspectors can verify authorization.
Question 3: Which OSHA standard specifically requires employers to conduct atmospheric testing before and during welding in a permit-required confined space?
- 29 CFR 1910.146 (Correct answer)
- 29 CFR 1910.252
- 29 CFR 1910.134
- 29 CFR 1910.119
Correct answer: 29 CFR 1910.146
OSHA 29 CFR 1910.146 governs permit-required confined spaces and mandates atmospheric testing before entry and continuously during work.
Question 4: What does the acronym 'SDS' stand for in the context of welding hazard communication?
- Safety Data Sheet (Correct answer)
- Substance Danger Summary
- Standard Disclosure Statement
- Structural Data Sheet
Correct answer: Safety Data Sheet
SDS stands for Safety Data Sheet, which provides hazard information for chemicals and materials encountered in welding.
Question 5: According to AWS F4.1, before welding or cutting is performed on a container that held flammable or combustible material, the container must be:
- Cleaned and purged to remove all residue and tested to confirm safe atmosphere (Correct answer)
- Filled completely with water before work begins
- Inspected visually for residue only
- Ventilated with a fan for 15 minutes
Correct answer: Cleaned and purged to remove all residue and tested to confirm safe atmosphere
AWS F4.1 requires thorough cleaning, purging, and atmospheric testing to confirm the container is safe before any hot work.
Question 6: What is the minimum air flow rate per welder specified by OSHA for natural or mechanical ventilation when welding in a room?
- 2,000 cubic feet per minute per welder (Correct answer)
- 500 cubic feet per minute per welder
- 1,000 cubic feet per minute per welder
- 4,000 cubic feet per minute per welder
Correct answer: 2,000 cubic feet per minute per welder
OSHA 1910.252(c) specifies a minimum of 2,000 CFM of air flow per welder in general welding areas without local exhaust ventilation.
Question 7: Which marking on a compressed gas cylinder indicates it has passed the required hydrostatic pressure test?
- A stamped date and inspector symbol on the cylinder shoulder (Correct answer)
- A colored label on the valve cap
- An inspector sticker on the side of the cylinder
- A green dot on the bottom of the cylinder
Correct answer: A stamped date and inspector symbol on the cylinder shoulder
DOT regulations require hydrostatic test dates and inspector markings to be permanently stamped on the cylinder shoulder.
WCL Safety Standards & Regulations 4
What hazard is created when welding is performed near degreasing solvents or chlorinated hydrocarbons such as trichloroethylene?