NFPA 10 Study Guide ACTUAL EXAM
2026/2027 | Portable Fire Extinguishers
NFPA 10 | Verified Q&A | Pass
Guaranteed - A+ Graded
Section 1: Fire Classes & Extinguisher Types (Questions 1–12)
Q1: A commercial kitchen fryer catches fire. Which class of fire is present and which extinguisher agent
is appropriate?
A. Class B; dry chemical (ABC)
B. Class K; wet chemical [CORRECT]
C. Class A; water mist
D. Class C; CO₂
Correct Answer: B
Rationale: Per NFPA 10 (2022/2026 ed.), Class K fires involve combustible cooking oils and fats. Wet
chemical agents (potassium acetate/potassium carbonate) are required because they undergo
saponification—creating a soapy foam layer that cools the oil and prevents reignition. Standard Class B
agents (A) may extinguish the flame but lack the cooling/saponification properties needed for high-
temperature cooking oils, leading to re-flash. Water (C) causes a dangerous steam explosion/spread of
grease. CO₂ (D) provides insufficient cooling for Class K hazards.
Q2: Which of the following agents is most appropriate for a Class D fire involving magnesium shavings?
A. Multipurpose dry chemical (ABC).
B. Carbon Dioxide (CO₂).
C. Dry powder (copper or graphite based). [CORRECT]
,D. Halotron I (Clean Agent).
Correct Answer: C
Rationale: Class D fires involve combustible metals (magnesium, titanium, sodium). Only specific dry
powder agents (e.g., copper powder for magnesium) are effective. These powders smother the fire and
conduct heat away from the metal. Multipurpose dry chemical (A) is ineffective and can react violently
with burning metals. CO₂ (B) and Clean Agents (D) lack the smothering/heat absorption capacity
required for metal fires. Reference: NFPA 10, Section 6.3.
Q3: What does a numerical rating of 2A on a fire extinguisher indicate?
A. The extinguisher contains 2 gallons of water.
B. The extinguisher is effective on a fire 2 square feet in size.
C. The extinguisher has an extinguishing potential equivalent to 2.5 gallons of water. [CORRECT]
D. The extinguisher can be used up to 2 feet away from the fire.
Correct Answer: C
Rationale: For Class A ratings, the number preceding the 'A' indicates the relative extinguishing
potential. Specifically, 1A is equivalent to 1.25 gallons of water. Therefore, a 2A rating indicates an
extinguishing potential of 2.5 gallons of water (2 x 1.25 = 2.5). Option B describes the logic for Class B
ratings (square footage). Reference: NFPA 10, Section 5.4.1.
Q4: A fire involves energized electrical panels and wiring. This is classified as a:
A. Class A fire.
B. Class B fire.
C. Class C fire. [CORRECT]
D. Class D fire.
Correct Answer: C
,Rationale: Class C fires involve energized electrical equipment. Once the electricity is de-energized, the
fire becomes Class A (insulation/wood) or Class B (oils/fluids), but while energized, it is Class C. Agents
must be non-conductive (CO₂, dry chemical, clean agents). Water-based extinguishers (A) are strictly
prohibited due to the risk of electrocution. Reference: NFPA 10, Section 5.3.
Q5: Select All That Apply (SATA) Which of the following agents are approved for use on Class B
(flammable liquid) fires? (Select all that apply)
A. Water (APW).
B. Carbon Dioxide (CO₂). *CORRECT+
C. Aqueous Film-Forming Foam (AFFF). [CORRECT]
D. Dry Chemical (BC). [CORRECT]
E. Water Mist.
Correct Answer: B, C, D
Rationale: Class B fires involve flammable liquids. CO₂ (B) displaces oxygen and cools. AFFF (C) creates a
film that seals the fuel surface. Dry Chemical (D) interrupts the chemical chain reaction. Water (A) is
ineffective on flammable liquids (unless used in a special water mist nozzle in very specific applications,
but standard APW spreads the fire). Reference: NFPA 10, Section 6.2.
Q6: What is the primary difference between a "dry chemical" and a "dry powder" extinguisher?
A. Dry chemical is for Class B fires; dry powder is for Class K.
B. Dry chemical is for Class A, B, C; dry powder is for Class D. [CORRECT]
C. Dry powder is conductive; dry chemical is non-conductive.
D. There is no difference; terms are interchangeable.
Correct Answer: B
Rationale: Dry Chemical agents (e.g., Monoammonium Phosphate) are used for Class A, B, and C fires.
Dry Powder agents are specifically formulated for Class D (combustible metal) fires. Using a dry chemical
on a metal fire can be ineffective or explosive. Reference: NFPA 10, Section 3.3 and 6.3.
, Q7: Which extinguisher type does NOT have a numerical rating for Class C?
A. Because the amount of agent needed varies too much.
B. Because the Class C classification only indicates the agent is non-conductive. [CORRECT]
C. Because electrical fires are always Class A.
D. Because CO₂ pressure varies with temperature.
Correct Answer: B
Rationale: The "C" classification on an extinguisher does not represent a quantity of extinguishing agent;
it simply indicates that the agent is non-conductive and safe for use on energized electrical equipment.
If the electrical power is cut, the fire is rated by the fuel type (A or B). Reference: NFPA 10, Section 5.4.3.
Q8: Diagram-Label Question (Textual) You are inspecting a stored-pressure fire extinguisher. You
identify a small cylindrical device screwed into the valve body with a yellow or red center that pops out
when the extinguisher is discharged. What is this component?
A. Safety pin.
B. Pressure gauge.
C. Tamper seal.
D. Pressure-relief device (burst disc). [CORRECT]
Correct Answer: D
Rationale: The pressure-relief device (often a burst disc or fusible plug) is designed to vent pressure to
prevent cylinder rupture if the extinguisher is exposed to fire or excessive heat/pressure. It is typically
located on the valve body (sometimes on the bottom for CO₂). The pressure gauge (B) indicates internal
pressure. The safety pin (A) prevents accidental handle depression.
Q9: Which extinguisher agent is known for "saponification" when applied to cooking oil?
A. Halotron I.
2026/2027 | Portable Fire Extinguishers
NFPA 10 | Verified Q&A | Pass
Guaranteed - A+ Graded
Section 1: Fire Classes & Extinguisher Types (Questions 1–12)
Q1: A commercial kitchen fryer catches fire. Which class of fire is present and which extinguisher agent
is appropriate?
A. Class B; dry chemical (ABC)
B. Class K; wet chemical [CORRECT]
C. Class A; water mist
D. Class C; CO₂
Correct Answer: B
Rationale: Per NFPA 10 (2022/2026 ed.), Class K fires involve combustible cooking oils and fats. Wet
chemical agents (potassium acetate/potassium carbonate) are required because they undergo
saponification—creating a soapy foam layer that cools the oil and prevents reignition. Standard Class B
agents (A) may extinguish the flame but lack the cooling/saponification properties needed for high-
temperature cooking oils, leading to re-flash. Water (C) causes a dangerous steam explosion/spread of
grease. CO₂ (D) provides insufficient cooling for Class K hazards.
Q2: Which of the following agents is most appropriate for a Class D fire involving magnesium shavings?
A. Multipurpose dry chemical (ABC).
B. Carbon Dioxide (CO₂).
C. Dry powder (copper or graphite based). [CORRECT]
,D. Halotron I (Clean Agent).
Correct Answer: C
Rationale: Class D fires involve combustible metals (magnesium, titanium, sodium). Only specific dry
powder agents (e.g., copper powder for magnesium) are effective. These powders smother the fire and
conduct heat away from the metal. Multipurpose dry chemical (A) is ineffective and can react violently
with burning metals. CO₂ (B) and Clean Agents (D) lack the smothering/heat absorption capacity
required for metal fires. Reference: NFPA 10, Section 6.3.
Q3: What does a numerical rating of 2A on a fire extinguisher indicate?
A. The extinguisher contains 2 gallons of water.
B. The extinguisher is effective on a fire 2 square feet in size.
C. The extinguisher has an extinguishing potential equivalent to 2.5 gallons of water. [CORRECT]
D. The extinguisher can be used up to 2 feet away from the fire.
Correct Answer: C
Rationale: For Class A ratings, the number preceding the 'A' indicates the relative extinguishing
potential. Specifically, 1A is equivalent to 1.25 gallons of water. Therefore, a 2A rating indicates an
extinguishing potential of 2.5 gallons of water (2 x 1.25 = 2.5). Option B describes the logic for Class B
ratings (square footage). Reference: NFPA 10, Section 5.4.1.
Q4: A fire involves energized electrical panels and wiring. This is classified as a:
A. Class A fire.
B. Class B fire.
C. Class C fire. [CORRECT]
D. Class D fire.
Correct Answer: C
,Rationale: Class C fires involve energized electrical equipment. Once the electricity is de-energized, the
fire becomes Class A (insulation/wood) or Class B (oils/fluids), but while energized, it is Class C. Agents
must be non-conductive (CO₂, dry chemical, clean agents). Water-based extinguishers (A) are strictly
prohibited due to the risk of electrocution. Reference: NFPA 10, Section 5.3.
Q5: Select All That Apply (SATA) Which of the following agents are approved for use on Class B
(flammable liquid) fires? (Select all that apply)
A. Water (APW).
B. Carbon Dioxide (CO₂). *CORRECT+
C. Aqueous Film-Forming Foam (AFFF). [CORRECT]
D. Dry Chemical (BC). [CORRECT]
E. Water Mist.
Correct Answer: B, C, D
Rationale: Class B fires involve flammable liquids. CO₂ (B) displaces oxygen and cools. AFFF (C) creates a
film that seals the fuel surface. Dry Chemical (D) interrupts the chemical chain reaction. Water (A) is
ineffective on flammable liquids (unless used in a special water mist nozzle in very specific applications,
but standard APW spreads the fire). Reference: NFPA 10, Section 6.2.
Q6: What is the primary difference between a "dry chemical" and a "dry powder" extinguisher?
A. Dry chemical is for Class B fires; dry powder is for Class K.
B. Dry chemical is for Class A, B, C; dry powder is for Class D. [CORRECT]
C. Dry powder is conductive; dry chemical is non-conductive.
D. There is no difference; terms are interchangeable.
Correct Answer: B
Rationale: Dry Chemical agents (e.g., Monoammonium Phosphate) are used for Class A, B, and C fires.
Dry Powder agents are specifically formulated for Class D (combustible metal) fires. Using a dry chemical
on a metal fire can be ineffective or explosive. Reference: NFPA 10, Section 3.3 and 6.3.
, Q7: Which extinguisher type does NOT have a numerical rating for Class C?
A. Because the amount of agent needed varies too much.
B. Because the Class C classification only indicates the agent is non-conductive. [CORRECT]
C. Because electrical fires are always Class A.
D. Because CO₂ pressure varies with temperature.
Correct Answer: B
Rationale: The "C" classification on an extinguisher does not represent a quantity of extinguishing agent;
it simply indicates that the agent is non-conductive and safe for use on energized electrical equipment.
If the electrical power is cut, the fire is rated by the fuel type (A or B). Reference: NFPA 10, Section 5.4.3.
Q8: Diagram-Label Question (Textual) You are inspecting a stored-pressure fire extinguisher. You
identify a small cylindrical device screwed into the valve body with a yellow or red center that pops out
when the extinguisher is discharged. What is this component?
A. Safety pin.
B. Pressure gauge.
C. Tamper seal.
D. Pressure-relief device (burst disc). [CORRECT]
Correct Answer: D
Rationale: The pressure-relief device (often a burst disc or fusible plug) is designed to vent pressure to
prevent cylinder rupture if the extinguisher is exposed to fire or excessive heat/pressure. It is typically
located on the valve body (sometimes on the bottom for CO₂). The pressure gauge (B) indicates internal
pressure. The safety pin (A) prevents accidental handle depression.
Q9: Which extinguisher agent is known for "saponification" when applied to cooking oil?
A. Halotron I.
