Welding Fundamentals for
Construction Exams – Full Practice
Test (2026 Curriculum) :Questions
and answer with rationals/graded
A+Update/100% correct
Section 1: Safety & Health (Questions 1–12)
1. The primary purpose of a welding helmet with a proper shade lens is to
protect against:
a) Sparks and slag
b) Ultraviolet (UV) and infrared (IR) radiation
c) Fumes and gases
d) Impact from falling objects
Correct Answer: b) Ultraviolet (UV) and infrared (IR) radiation
Rationale: UV/IR radiation from the arc causes “arc flash” (photokeratitis) and retinal
burns. Helmets block these, while safety glasses address impact.
2. Which gas is most commonly produced during welding that can displace
oxygen in confined spaces?
a) Carbon monoxide
b) Ozone
c) Carbon dioxide
d) Argon
Correct Answer: c) Carbon dioxide (or d) Argon – both are heavy, but CO₂ is most
common in shielded metal arc welding)
Rationale: Both argon and CO₂ are heavier than air and can settle in low areas,
displacing oxygen. CO₂ is more frequently cited in confined space incidents for steel
welding.
,3. The maximum allowable airborne concentration of hexavalent chromium
(Cr(VI)) for an 8-hour workday under OSHA 2026 standards is:
a) 0.5 µg/m³
b) 5.0 µg/m³
c) 50 µg/m³
d) 100 µg/m³
Correct Answer: b) 5.0 µg/m³
*Rationale: OSHA’s PEL for Cr(VI) is 5 µg/m³. Cr(VI) is produced when welding
stainless steel or chromium-alloyed metals.*
4. What class of fire extinguisher is required for electrical fires (e.g., welding
machine short circuit)?
a) Class A
b) Class B
c) Class C
d) Class D
Correct Answer: c) Class C
Rationale: Class C extinguishers (non-conductive agents) are for energized electrical
equipment. Class D is for combustible metals.
5. Which of the following is NOT a component of the flash fire triangle or
explosion pentagon?
a) Fuel
b) Oxidizer
c) Inert gas shield
d) Ignition source
Correct Answer: c) Inert gas shield
Rationale: Inert gases (argon, helium) prevent combustion by displacing oxygen; they
are not part of the fire triangle.
6. When welding in a confined space, the first safety step is:
a) Have a fire watch outside
b) Ventilate with fresh air
c) Test the atmosphere for oxygen and flammables
d) Wear a leather apron
Correct Answer: c) Test the atmosphere for oxygen and flammables
Rationale: Atmospheric testing (O₂, LEL, toxic gases) is required before entry per OSHA
1910.146.
7. “Fume fever” is primarily caused by welding:
a) Galvanized steel (zinc)
, b) Aluminum
c) Cast iron
d) Titanium
Correct Answer: a) Galvanized steel (zinc)
Rationale: Zinc oxide fumes cause metal fume fever (flu-like symptoms).
8. The minimum recommended shade number for SMAW (stick) welding at 125
amps is:
a) Shade 8
b) Shade 10
c) Shade 12
d) Shade 14
Correct Answer: b) Shade 10
*Rationale: AWS Z49.1: 100-175 amps → shade 10. Below 60A → shade 8; >250A →
shade 12+.*
9. Which material should never be welded without special ventilation due to
production of phosgene gas?
a) Brass
b) Lead-coated steel
c) Plastics or metals with chlorinated solvent residues
d) Aluminum bronze
Correct Answer: c) Plastics or metals with chlorinated solvent residues
Rationale: UV from arc decomposes chlorinated solvents (e.g., trichloroethylene) into
phosgene (toxic gas).
10. Grounding of the welding machine serves to:
a) Increase welding current
b) Provide a return path for welding current and prevent electric shock
c) Reduce spatter
d) Stabilize the arc
Correct Answer: b) Provide a return path for welding current and prevent
electric shock
Rationale: The work lead completes the circuit; equipment grounding conductor
prevents shock from faults.
11. A “fire watch” must be maintained for at least ______ after welding in a fire-
risk area per 2026 NFPA 51B.
a) 15 minutes
b) 30 minutes
Construction Exams – Full Practice
Test (2026 Curriculum) :Questions
and answer with rationals/graded
A+Update/100% correct
Section 1: Safety & Health (Questions 1–12)
1. The primary purpose of a welding helmet with a proper shade lens is to
protect against:
a) Sparks and slag
b) Ultraviolet (UV) and infrared (IR) radiation
c) Fumes and gases
d) Impact from falling objects
Correct Answer: b) Ultraviolet (UV) and infrared (IR) radiation
Rationale: UV/IR radiation from the arc causes “arc flash” (photokeratitis) and retinal
burns. Helmets block these, while safety glasses address impact.
2. Which gas is most commonly produced during welding that can displace
oxygen in confined spaces?
a) Carbon monoxide
b) Ozone
c) Carbon dioxide
d) Argon
Correct Answer: c) Carbon dioxide (or d) Argon – both are heavy, but CO₂ is most
common in shielded metal arc welding)
Rationale: Both argon and CO₂ are heavier than air and can settle in low areas,
displacing oxygen. CO₂ is more frequently cited in confined space incidents for steel
welding.
,3. The maximum allowable airborne concentration of hexavalent chromium
(Cr(VI)) for an 8-hour workday under OSHA 2026 standards is:
a) 0.5 µg/m³
b) 5.0 µg/m³
c) 50 µg/m³
d) 100 µg/m³
Correct Answer: b) 5.0 µg/m³
*Rationale: OSHA’s PEL for Cr(VI) is 5 µg/m³. Cr(VI) is produced when welding
stainless steel or chromium-alloyed metals.*
4. What class of fire extinguisher is required for electrical fires (e.g., welding
machine short circuit)?
a) Class A
b) Class B
c) Class C
d) Class D
Correct Answer: c) Class C
Rationale: Class C extinguishers (non-conductive agents) are for energized electrical
equipment. Class D is for combustible metals.
5. Which of the following is NOT a component of the flash fire triangle or
explosion pentagon?
a) Fuel
b) Oxidizer
c) Inert gas shield
d) Ignition source
Correct Answer: c) Inert gas shield
Rationale: Inert gases (argon, helium) prevent combustion by displacing oxygen; they
are not part of the fire triangle.
6. When welding in a confined space, the first safety step is:
a) Have a fire watch outside
b) Ventilate with fresh air
c) Test the atmosphere for oxygen and flammables
d) Wear a leather apron
Correct Answer: c) Test the atmosphere for oxygen and flammables
Rationale: Atmospheric testing (O₂, LEL, toxic gases) is required before entry per OSHA
1910.146.
7. “Fume fever” is primarily caused by welding:
a) Galvanized steel (zinc)
, b) Aluminum
c) Cast iron
d) Titanium
Correct Answer: a) Galvanized steel (zinc)
Rationale: Zinc oxide fumes cause metal fume fever (flu-like symptoms).
8. The minimum recommended shade number for SMAW (stick) welding at 125
amps is:
a) Shade 8
b) Shade 10
c) Shade 12
d) Shade 14
Correct Answer: b) Shade 10
*Rationale: AWS Z49.1: 100-175 amps → shade 10. Below 60A → shade 8; >250A →
shade 12+.*
9. Which material should never be welded without special ventilation due to
production of phosgene gas?
a) Brass
b) Lead-coated steel
c) Plastics or metals with chlorinated solvent residues
d) Aluminum bronze
Correct Answer: c) Plastics or metals with chlorinated solvent residues
Rationale: UV from arc decomposes chlorinated solvents (e.g., trichloroethylene) into
phosgene (toxic gas).
10. Grounding of the welding machine serves to:
a) Increase welding current
b) Provide a return path for welding current and prevent electric shock
c) Reduce spatter
d) Stabilize the arc
Correct Answer: b) Provide a return path for welding current and prevent
electric shock
Rationale: The work lead completes the circuit; equipment grounding conductor
prevents shock from faults.
11. A “fire watch” must be maintained for at least ______ after welding in a fire-
risk area per 2026 NFPA 51B.
a) 15 minutes
b) 30 minutes
