Certified Welder Safety and Equipment Setup 3 — Questions and Answers
Question 1: What is the correct action if you smell acetylene in a welding area?
- Immediately ignite the torch to burn off the gas
- Evacuate, ventilate, and locate the leak before re-entering (Correct answer)
- Turn on additional ventilation fans and continue working
- Reduce oxygen flow to balance the mixture
Correct answer: Evacuate, ventilate, and locate the leak before re-entering
Acetylene is highly flammable, so the area must be evacuated and ventilated, and the leak source found before resuming work.
Question 2: Which welding process typically requires a shielding gas to protect the weld pool from atmospheric contamination?
- Shielded Metal Arc Welding (SMAW)
- Oxy-acetylene welding
- Gas Metal Arc Welding (GMAW) (Correct answer)
- Submerged Arc Welding (SAW)
Correct answer: Gas Metal Arc Welding (GMAW)
GMAW (MIG welding) uses an external shielding gas such as argon, CO2, or a mix to protect the molten weld pool.
Question 3: What is the safe maximum acetylene withdrawal rate from a cylinder to prevent drawing acetone into the system?
- 1/10 of cylinder capacity per hour
- 1/7 of cylinder capacity per hour (Correct answer)
- 1/3 of cylinder capacity per hour
- Full flow at any rate is acceptable
Correct answer: 1/7 of cylinder capacity per hour
Acetylene should not be withdrawn faster than 1/7 of the cylinder's capacity per hour to prevent acetone contamination.
Question 4: Which personal protective equipment is specifically required to protect a welder's lungs from hexavalent chromium when welding stainless steel?
- A standard N95 particulate respirator
- Supplied-air respirator or HEPA-filtered respirator (Correct answer)
- Face shield only
- No special respiratory protection is required for stainless
Correct answer: Supplied-air respirator or HEPA-filtered respirator
Welding stainless steel produces hexavalent chromium (Cr(VI)), a known carcinogen requiring HEPA filtration or supplied air.
Question 5: What is the function of a flashback arrestor on an oxy-fuel torch system?
- Regulate gas pressure at the regulator
- Prevent flame from traveling back into the hoses and cylinders (Correct answer)
- Filter moisture from gas lines
- Control the ratio of fuel to oxygen
Correct answer: Prevent flame from traveling back into the hoses and cylinders
Flashback arrestors contain check valves and thermal cutoffs that stop a reverse flame from reaching the hoses and cylinders.
Question 6: When setting up a MIG welder, the wire feed speed primarily controls which welding parameter?
- Arc voltage
- Amperage (current) (Correct answer)
- Shielding gas flow rate
- Travel speed
Correct answer: Amperage (current)
In GMAW, wire feed speed directly controls amperage because more wire requires more current to melt it.
Question 7: Which condition makes a confined space permit-required for welding operations?
- The space has only one entry point
- The space contains or has the potential for hazardous atmosphere or engulfment hazards (Correct answer)
- The space is smaller than 4 feet in any dimension
- The space requires kneeling or crawling to enter
Correct answer: The space contains or has the potential for hazardous atmosphere or engulfment hazards
A permit-required confined space is defined by the presence of potential hazardous atmospheres, engulfment, or other serious safety hazards.
Certified Welder Safety and Equipment Setup 3
What is the correct action if you smell acetylene in a welding area?