NCCER Boilermaker Craft Certification Exam –
NCCER V4 Curriculum-Aligned Program,
2026/2027 Questions with Correct Answers and
Detailed Rationales
1. According to OSHA 1926 Subpart C, what is the primary responsibility of
employers regarding workplace safety?
A. To provide tools only when requested by employees
B. To furnish employment and a place of employment free from recognized
hazards
C. To ensure only management personnel receive safety training
D. To delegate all safety responsibilities to the employees
Answer: B
Rationale: OSHA 1926 Subpart C mandates that employers shall furnish a place of
employment free from recognized hazards that are likely to cause death or serious
physical harm.
2. Under 29 CFR 1910.146, which of the following defines a permit-required
confined space?
A. Any space with a ceiling height less than six feet
B. A space that contains or has the potential to contain a hazardous
atmosphere, engulfment hazard, or other serious safety or health hazard
C. Any enclosed area with only one point of entry
D. A space where temperatures may exceed 100 degrees Fahrenheit
Answer: B
Rationale: A permit-required confined space has one or more of: hazardous
atmosphere, engulfment hazard, internal configuration that could trap, or other
serious hazard.
3. When selecting personal protective equipment (PPE) for boilermaker operations,
which standard governs the employer's hazard assessment and equipment selection
,requirements?
A. OSHA 29 CFR 1926 Subpart X — Demolition
B. OSHA 29 CFR 1926 Subpart E — Personal Protective and Life Saving
Equipment
C. OSHA 29 CFR 1910.132 — General Requirements for Personal Protective
Equipment
D. ANSI Z359.1 — Fall Protection Code
Answer: C
Rationale: 29 CFR 1910.132 requires employers to perform a hazard assessment
and select appropriate PPE, which is foundational for boilermaker safety.
4. What is the purpose of a Lockout/Tagout (LOTO) procedure under 29 CFR
1910.147?
A. To secure tools at the end of a work shift
B. To prevent the unexpected energization or startup of machinery and
equipment during servicing or maintenance
C. To mark completed work areas for quality inspection
D. To prevent unauthorized personnel from entering the job site
Answer: B
Rationale: LOTO ensures that energy-isolating devices are locked/tagged to
prevent accidental startup, protecting workers servicing equipment.
5. Under the Hazard Communication Standard (HCS) 29 CFR 1910.1200, which
document provides workers with information about chemical hazards in the
workplace?
A. Material Safety Data Sheet (MSDS) or Safety Data Sheet (SDS)
B. Job Hazard Analysis (JHA)
C. Confined Space Entry Permit
D. Lockout/Tagout Log
Answer: A
Rationale: SDSs (formerly MSDS) provide detailed chemical hazard information,
safe handling, and emergency procedures.
,6. When performing work at heights of six feet or greater in the construction
industry, which OSHA standard applies to fall protection requirements?
A. OSHA 29 CFR 1910.23 – Guarding Floor and Wall Openings
B. OSHA 29 CFR 1926.502 – Fall Protection Systems Criteria and Practices
C. OSHA 29 CFR 1910.66 – Powered Platforms
D. OSHA 29 CFR 1926.100 – Head Protection
Answer: B
Rationale: 29 CFR 1926 Subpart M requires fall protection at heights ≥6 feet;
Section 1926.502 specifies criteria for guardrails, nets, and personal arrest
systems.
7. What is the minimum safe oxygen concentration for human occupancy in a
confined space, according to OSHA and NCCER standards?
A. 15.5%
B. 18.5%
C. 19.5%
D. 21.0%
Answer: C
Rationale: OSHA defines a safe oxygen range as 19.5%–23.5%. Below 19.5% is
oxygen-deficient and may cause impaired judgment or death.
8. Which type of fire extinguisher is appropriate for use on Class B fires involving
flammable liquids such as cutting oils or solvents?
A. Class A – water-based extinguisher
B. Class B – CO₂ or dry chemical extinguisher
C. Class C – Halon extinguisher only
D. Class D – dry powder extinguisher for combustible metals
Answer: B
Rationale: Class B extinguishers (CO₂, dry chemical) are designed for flammable
liquid fires. Class A is for ordinary combustibles; Class C for electrical; Class D
for combustible metals.
, 9. According to OSHA 29 CFR 1926.451, what is the maximum gap allowed
between a scaffold platform and the building face?
A. 6 inches
B. 14 inches
C. 18 inches
D. 24 inches
Answer: B
Rationale: Scaffold platforms must be within 14 inches of the building face to
prevent falls, unless guardrails are installed.
10. What is the primary hazard when using an oxy-fuel cutting torch near
combustible materials?
A. Ultraviolet radiation
B. Fire and explosion
C. Electric shock
D. Toxic fumes only
Answer: B
Rationale: Oxy-fuel torches produce intense heat and sparks, easily igniting
combustibles; fire watch and clearance are required.
11. Under OSHA 29 CFR 1910.1200, how many sections does a Safety Data Sheet
(SDS) contain under the GHS system?
A. 8
B. 12
C. 16
D. 20
Answer: C
Rationale: The Globally Harmonized System (GHS) standardizes SDSs into 16
sections, including identification, hazards, composition, first-aid, and handling.
12. What is the correct procedure for donning a half-mask air-purifying respirator?
A. Perform a user seal check after donning
B. Don the respirator over facial hair for better fit
NCCER V4 Curriculum-Aligned Program,
2026/2027 Questions with Correct Answers and
Detailed Rationales
1. According to OSHA 1926 Subpart C, what is the primary responsibility of
employers regarding workplace safety?
A. To provide tools only when requested by employees
B. To furnish employment and a place of employment free from recognized
hazards
C. To ensure only management personnel receive safety training
D. To delegate all safety responsibilities to the employees
Answer: B
Rationale: OSHA 1926 Subpart C mandates that employers shall furnish a place of
employment free from recognized hazards that are likely to cause death or serious
physical harm.
2. Under 29 CFR 1910.146, which of the following defines a permit-required
confined space?
A. Any space with a ceiling height less than six feet
B. A space that contains or has the potential to contain a hazardous
atmosphere, engulfment hazard, or other serious safety or health hazard
C. Any enclosed area with only one point of entry
D. A space where temperatures may exceed 100 degrees Fahrenheit
Answer: B
Rationale: A permit-required confined space has one or more of: hazardous
atmosphere, engulfment hazard, internal configuration that could trap, or other
serious hazard.
3. When selecting personal protective equipment (PPE) for boilermaker operations,
which standard governs the employer's hazard assessment and equipment selection
,requirements?
A. OSHA 29 CFR 1926 Subpart X — Demolition
B. OSHA 29 CFR 1926 Subpart E — Personal Protective and Life Saving
Equipment
C. OSHA 29 CFR 1910.132 — General Requirements for Personal Protective
Equipment
D. ANSI Z359.1 — Fall Protection Code
Answer: C
Rationale: 29 CFR 1910.132 requires employers to perform a hazard assessment
and select appropriate PPE, which is foundational for boilermaker safety.
4. What is the purpose of a Lockout/Tagout (LOTO) procedure under 29 CFR
1910.147?
A. To secure tools at the end of a work shift
B. To prevent the unexpected energization or startup of machinery and
equipment during servicing or maintenance
C. To mark completed work areas for quality inspection
D. To prevent unauthorized personnel from entering the job site
Answer: B
Rationale: LOTO ensures that energy-isolating devices are locked/tagged to
prevent accidental startup, protecting workers servicing equipment.
5. Under the Hazard Communication Standard (HCS) 29 CFR 1910.1200, which
document provides workers with information about chemical hazards in the
workplace?
A. Material Safety Data Sheet (MSDS) or Safety Data Sheet (SDS)
B. Job Hazard Analysis (JHA)
C. Confined Space Entry Permit
D. Lockout/Tagout Log
Answer: A
Rationale: SDSs (formerly MSDS) provide detailed chemical hazard information,
safe handling, and emergency procedures.
,6. When performing work at heights of six feet or greater in the construction
industry, which OSHA standard applies to fall protection requirements?
A. OSHA 29 CFR 1910.23 – Guarding Floor and Wall Openings
B. OSHA 29 CFR 1926.502 – Fall Protection Systems Criteria and Practices
C. OSHA 29 CFR 1910.66 – Powered Platforms
D. OSHA 29 CFR 1926.100 – Head Protection
Answer: B
Rationale: 29 CFR 1926 Subpart M requires fall protection at heights ≥6 feet;
Section 1926.502 specifies criteria for guardrails, nets, and personal arrest
systems.
7. What is the minimum safe oxygen concentration for human occupancy in a
confined space, according to OSHA and NCCER standards?
A. 15.5%
B. 18.5%
C. 19.5%
D. 21.0%
Answer: C
Rationale: OSHA defines a safe oxygen range as 19.5%–23.5%. Below 19.5% is
oxygen-deficient and may cause impaired judgment or death.
8. Which type of fire extinguisher is appropriate for use on Class B fires involving
flammable liquids such as cutting oils or solvents?
A. Class A – water-based extinguisher
B. Class B – CO₂ or dry chemical extinguisher
C. Class C – Halon extinguisher only
D. Class D – dry powder extinguisher for combustible metals
Answer: B
Rationale: Class B extinguishers (CO₂, dry chemical) are designed for flammable
liquid fires. Class A is for ordinary combustibles; Class C for electrical; Class D
for combustible metals.
, 9. According to OSHA 29 CFR 1926.451, what is the maximum gap allowed
between a scaffold platform and the building face?
A. 6 inches
B. 14 inches
C. 18 inches
D. 24 inches
Answer: B
Rationale: Scaffold platforms must be within 14 inches of the building face to
prevent falls, unless guardrails are installed.
10. What is the primary hazard when using an oxy-fuel cutting torch near
combustible materials?
A. Ultraviolet radiation
B. Fire and explosion
C. Electric shock
D. Toxic fumes only
Answer: B
Rationale: Oxy-fuel torches produce intense heat and sparks, easily igniting
combustibles; fire watch and clearance are required.
11. Under OSHA 29 CFR 1910.1200, how many sections does a Safety Data Sheet
(SDS) contain under the GHS system?
A. 8
B. 12
C. 16
D. 20
Answer: C
Rationale: The Globally Harmonized System (GHS) standardizes SDSs into 16
sections, including identification, hazards, composition, first-aid, and handling.
12. What is the correct procedure for donning a half-mask air-purifying respirator?
A. Perform a user seal check after donning
B. Don the respirator over facial hair for better fit
