AWS Welding Safety & OSHA Regulations 5 — Questions and Answers
Question 1: A welder is asked to weld a drum that previously contained a flammable solvent. What is the FIRST required step before welding can begin?
- Apply a fire-resistant coating to the outside of the drum
- Test the drum with an explosimeter and purge or fill with water/inert gas (Correct answer)
- Weld quickly to minimize time exposed to residual vapors
- Install a local exhaust ventilation system near the drum
Correct answer: Test the drum with an explosimeter and purge or fill with water/inert gas
Containers that held flammable materials must be tested for explosive vapors and purged or filled with water/inert gas before any hot work, per AWS F4.1 and OSHA guidelines.
Question 2: Which OSHA permissible exposure limit (PEL) applies to manganese fumes generated during welding operations in general industry?
- 0.2 mg/m³ as an 8-hour TWA
- 1.0 mg/m³ as a ceiling value (Correct answer)
- 5 mg/m³ as an 8-hour TWA
- 0.02 mg/m³ as a 15-minute STEL
Correct answer: 1.0 mg/m³ as a ceiling value
OSHA's PEL for manganese fume in general industry is a ceiling value of 1.0 mg/m³ that must not be exceeded at any time.
Question 3: What is the purpose of a 'hot work permit' system in a facility?
- To document welder certification credentials before starting a job
- To authorize and control ignition sources in areas with fire hazards (Correct answer)
- To ensure welders are compensated for hazardous duty work
- To satisfy AWS certification renewal requirements
Correct answer: To authorize and control ignition sources in areas with fire hazards
A hot work permit system is a hazard control administrative procedure that authorizes ignition-source activities in areas where fire or explosion risks exist.
Question 4: When welding outdoors in windy conditions, local exhaust ventilation (LEV) may become ineffective. What is the recommended minimum wind speed threshold that typically requires a windbreak or alternate controls?
- 2 mph
- 4 mph (Correct answer)
- 6 mph
- 10 mph
Correct answer: 4 mph
Winds exceeding approximately 4 mph can displace local exhaust ventilation capture zones, requiring windbreaks or alternative fume control methods.
Question 5: Under OSHA 29 CFR 1910.252(a)(2)(iv), when welding near sprinkler systems, the welder must ensure sprinkler heads are protected from spatter. If sprinkler heads are covered, who is responsible for removing the covers after welding?
- The welder who installed the covers
- A designated fire watch (Correct answer)
- The facility safety officer
- Building maintenance within 24 hours
Correct answer: A designated fire watch
OSHA requires a fire watch to monitor for fire and also to ensure that protective covers on sprinkler heads are removed promptly after hot work is completed.
Question 6: Which of the following welding fume components is classified as a Group 1 human carcinogen by the International Agency for Research on Cancer (IARC)?
- Iron oxide
- Zinc oxide
- Hexavalent chromium (Cr VI) (Correct answer)
- Calcium fluoride
Correct answer: Hexavalent chromium (Cr VI)
Hexavalent chromium (Cr VI), generated when welding stainless steel and chrome-alloy materials, is classified as a Group 1 (definite) human carcinogen by IARC.
Question 7: A welder notices that the insulation on the electrode holder cable is cracked and the bare copper conductor is partially exposed. According to OSHA electrical safety standards, the welder should:
- Wrap the exposed area with electrical tape and continue working
- Reduce the amperage setting to lower the risk and complete the task
- Immediately remove the equipment from service and tag it out (Correct answer)
- Continue only if wearing rubber gloves rated for the voltage
Correct answer: Immediately remove the equipment from service and tag it out
Damaged insulation exposing conductors creates an electrocution hazard; the equipment must be immediately taken out of service and tagged for repair before further use.
AWS Welding Safety & OSHA Regulations 5
A welder is asked to weld a drum that previously contained a flammable solvent.
What is the FIRST required step before welding can begin?