CWS Welding Safety & Quality Control — Questions and Answers
Question 1: Per ANSI Z49.1 and NFPA 51B, combustible materials that cannot be protected should be relocated at least how far from a hot work location?
- 10 ft (3 m)
- 20 ft (6 m)
- 35 ft (11 m) (Correct answer)
- 50 ft (15 m)
Correct answer: 35 ft (11 m)
The 35 ft (11 m) rule is the standard radius for removing or protecting combustibles around hot work.
Question 2: Under OSHA 1910.253, stored oxygen cylinders must be separated from fuel-gas cylinders by a minimum of 20 ft or by a noncombustible barrier of what height?
- 3 ft
- 5 ft (Correct answer)
- 6 ft
- 8 ft
Correct answer: 5 ft
OSHA requires 20 ft separation or a noncombustible barrier at least 5 ft high with a half-hour fire-resistance rating.
Question 3: Acetylene should never be used at a withdrawal pressure exceeding which value?
- 5 psig
- 10 psig
- 15 psig (Correct answer)
- 25 psig
Correct answer: 15 psig
Above 15 psig, acetylene becomes unstable and can decompose explosively.
Question 4: According to the AWS F2.2 lens shade selector, what is the suggested shade number for SMAW using a 3/16 in. electrode?
- Shade 8
- Shade 10
- Shade 12 (Correct answer)
- Shade 14
Correct answer: Shade 12
For 5/32–1/4 in. electrodes, the minimum shade is 10 and the suggested comfort shade is 12.
Question 5: Under AWS D1.1, which party is responsible for qualifying the WPSs and the welding personnel used on the job?
- The Engineer
- The Owner's inspector
- The Contractor (Correct answer)
- The steel supplier
Correct answer: The Contractor
D1.1 puts responsibility for WPS and welder qualification on the Contractor, while the Engineer may accept or require verification.
Question 6: A CWS needs to check welds on an austenitic stainless steel pressure line for surface cracks; which NDE method is NOT suitable?
- Liquid penetrant testing
- Visual testing
- Eddy current testing
- Magnetic particle testing (Correct answer)
Correct answer: Magnetic particle testing
Austenitic stainless steel is nonferromagnetic, so magnetic particle testing cannot produce indications.
Question 7: What is the OSHA permissible exposure limit (8-hr TWA) for hexavalent chromium, a common hazard when welding stainless steel?
- 0.5 µg/m³
- 5 µg/m³ (Correct answer)
- 50 µg/m³
- 500 µg/m³
Correct answer: 5 µg/m³
OSHA 1910.1026 sets the hexavalent chromium PEL at 5 µg/m³ as an 8-hour TWA.
Question 8: OSHA considers a confined-space atmosphere oxygen-deficient when oxygen content falls below what level?
- 16.0%
- 19.5% (Correct answer)
- 20.9%
- 23.5%
Correct answer: 19.5%
Below 19.5% oxygen the atmosphere is oxygen-deficient and hazardous.
Question 9: Why must pure oxygen never be used to ventilate or 'sweeten' a confined space before welding?
- It causes porosity in the weld
- Oxygen enrichment makes clothing and materials ignite and burn violently (Correct answer)
- It displaces the shielding gas only
- It triggers false readings on LEL meters only
Correct answer: Oxygen enrichment makes clothing and materials ignite and burn violently
Oxygen-enriched atmospheres (above 23.5%) make ordinary materials, including clothing, extremely flammable.
Question 10: Per AWS D1.1, final visual inspection of welds on ASTM A514 and A517 steels must be performed no sooner than how long after welding is completed?
- Immediately after cooling to ambient
- 12 hours
- 24 hours
- 48 hours (Correct answer)
Correct answer: 48 hours
The 48-hour delay allows delayed hydrogen-induced cracking to appear before acceptance.
Question 11: Under AWS D1.1, E70XX low-hydrogen electrodes removed from hermetically sealed containers may be exposed to the atmosphere for a maximum of how long?
- 1 hour
- 2 hours
- 4 hours (Correct answer)
- 8 hours
Correct answer: 4 hours
D1.1 limits E70XX exposure to 4 hours before the electrodes must be returned to a holding oven or rebaked.
Question 12: In an inspection and test plan, what does a 'hold point' require?
- Inspection is optional at the inspector's discretion
- Work cannot proceed until the designated inspection is performed and released (Correct answer)
- Documents are reviewed after the job ships
- Only a witness signature is needed after completion
Correct answer: Work cannot proceed until the designated inspection is performed and released
A hold point is a mandatory stop where work stays on hold until the specified party inspects and releases it.
Question 13: Where should the welding work lead be connected to reduce safety and equipment hazards?
- To the building steel as far away as possible
- As close to the weld area as practical on the workpiece (Correct answer)
- To any nearby pipe or conduit
- To the welding machine frame only
Correct answer: As close to the weld area as practical on the workpiece
A close work connection keeps stray welding current from flowing through chains, bearings, conduit, or structural members.
Question 14: What is the primary purpose of an image quality indicator (IQI or penetrameter) in radiographic testing?
- To measure weld reinforcement height
- To verify the radiograph's sensitivity and technique quality (Correct answer)
- To identify the welder who made the weld
- To calibrate the film density meter
Correct answer: To verify the radiograph's sensitivity and technique quality
The IQI shows whether the radiographic technique is sensitive enough to reveal discontinuities of the required size.
Question 15: Which control is generally most effective at keeping welding fumes out of the welder's breathing zone?
- General dilution ventilation from roof fans
- Local exhaust ventilation positioned near the arc (Correct answer)
- Opening shop doors
- A disposable dust mask
Correct answer: Local exhaust ventilation positioned near the arc
Local exhaust captures fumes at the source, which is preferred over dilution ventilation or PPE in the hierarchy of controls.
Question 16: Long-term overexposure to which welding fume constituent is linked to a Parkinson-like neurological disorder?
- Iron oxide
- Manganese (Correct answer)
- Zinc oxide
- Titanium dioxide
Correct answer: Manganese
Manganese overexposure can cause manganism, a neurological disorder resembling Parkinson's disease.
Question 17: A welder develops flu-like chills and fever several hours after welding galvanized steel; what is the most likely cause?
- Ozone poisoning
- Metal fume fever from zinc oxide (Correct answer)
- Carbon monoxide poisoning
- Phosgene exposure
Correct answer: Metal fume fever from zinc oxide
Inhaling zinc oxide fumes from galvanized coatings causes metal fume fever.
Question 18: Why must chlorinated hydrocarbon degreasing solvents be kept away from arc welding operations?
- They lower the arc voltage
- Arc UV radiation can break them down into toxic phosgene gas (Correct answer)
- They cause excessive spatter
- They raise the preheat temperature
Correct answer: Arc UV radiation can break them down into toxic phosgene gas
Ultraviolet radiation from the arc decomposes chlorinated solvent vapors into phosgene, a highly toxic gas.
Question 19: Per AWS D1.1 for statically loaded nontubular connections, what is the maximum undercut allowed on material 1 in. thick or greater?
- 1/64 in.
- 1/32 in.
- 1/16 in. (Correct answer)
- 1/8 in.
Correct answer: 1/16 in.
For material 1 in. or thicker, undercut must not exceed 1/16 in. for any length.
Question 20: When a nonconforming weld is proposed for a 'use-as-is' disposition, who must normally approve it?
- The welder who made it
- The shop foreman
- The responsible Engineer (Correct answer)
- The material supplier
Correct answer: The responsible Engineer
Accepting a nonconformance without repair is a design decision that requires the Engineer's approval and documentation.
Question 21: What is the main purpose of couplant in contact ultrasonic testing?
- To cool the transducer
- To remove air between transducer and surface so sound transfers (Correct answer)
- To clean the weld surface
- To magnetize the test area
Correct answer: To remove air between transducer and surface so sound transfers
Air blocks ultrasound transmission, so couplant fills the gap and transmits sound energy into the part.
