NFPA 90A Standard for the Installation
of Air-Conditioning and Ventilating
Systems Exam With Actual Questions
& Verified Answers,Plus
Rationales/Expert Verified For
Guaranteed Pass /2026 /Latest
Update/Instant Download Pdf
1. Which NFPA 90A section requires that air ducts be constructed
of noncombustible materials in certain occupancies?
A. Section 4.1
B. Section 5.2
C. Section 6.3
D. Section 7.4
B. Section 5.2
Rationale: Section 5.2 of NFPA 90A specifies that air ducts in certain
high-hazard or special occupancy applications must be constructed
of noncombustible materials to reduce fire spread.
2. What is the maximum permitted flame spread index for duct
linings in commercial buildings?
A. 25
B. 50
C. 75
D. 100
,B. 50
Rationale: NFPA 90A limits flame spread index to 25 or 50 for duct
linings depending on occupancy and location, ensuring reduced fire
propagation through HVAC systems.
3. Where are smoke detectors required in air-handling systems
according to NFPA 90A?
A. Only in return air ducts
B. Only in supply air ducts
C. In both supply and return air systems serving certain
occupancies
D. Not required in air-handling systems
C. In both supply and return air systems serving certain occupancies
Rationale: NFPA 90A mandates smoke detectors in both supply and
return ducts in certain occupancies to detect smoke early and
prevent system spread.
4. Which type of air duct joint is prohibited in smoke control
systems?
A. Welded
B. Riveted
C. Butt seam with gasket
D. All welded
B. Riveted
Rationale: Riveted duct joints are prohibited in smoke control
systems due to the potential for leakage; welded or properly sealed
joints are required.
5. NFPA 90A requires fire dampers in which location?
A. Supply ducts in office buildings
B. Ducts penetrating fire-resistance-rated assemblies
, C. Return air ducts only
D. Roof exhaust ducts
B. Ducts penetrating fire-resistance-rated assemblies
Rationale: Fire dampers are required where ducts penetrate walls,
floors, or partitions with a fire-resistance rating to maintain
compartmentation.
6. What is the minimum fire-resistance rating for a fire damper
assembly in a 2-hour rated wall?
A. 20 minutes
B. 45 minutes
C. 1 hour
D. 2 hours
C. 1 hour
Rationale: NFPA 90A requires fire dampers to have a rating at least
equal to the fire-resistance rating of the wall or floor penetration.
For a 2-hour wall, a 1-hour damper is typically acceptable if tested
accordingly.
7. NFPA 90A specifies that smoke dampers must close under
which conditions?
A. Only during a fire
B. When air velocity exceeds 2000 fpm
C. Upon actuation of smoke detection system
D. When the HVAC system shuts down manually
C. Upon actuation of smoke detection system
Rationale: Smoke dampers are linked to smoke detectors and close
automatically to prevent the spread of smoke through ducts.
8. What is the minimum clearance required around fire dampers
installed in walls?
, A. 1 inch
B. 2 inches
C. 3 inches
D. 4 inches
B. 2 inches
Rationale: NFPA 90A requires a minimum of 2-inch clearance
around dampers to ensure proper operation and avoid obstruction.
9. Which material is generally prohibited for interior duct lining in
most commercial HVAC systems?
A. Fiberglass
B. Mineral wool
C. Combustible material
D. Metal mesh
C. Combustible material
Rationale: Combustible duct materials can increase fire propagation
risk; NFPA 90A limits combustible materials in duct interiors.
10. How often must fire dampers be inspected and tested
according to NFPA 90A?
A. Annually
B. Every 2 years
C. Every 5 years
D. Only after installation
A. Annually
Rationale: NFPA 90A and NFPA 80 require annual inspection and
operational testing of fire dampers to ensure proper function.
11. What is the primary purpose of an HVAC smoke control
system?
A. Cooling supply
of Air-Conditioning and Ventilating
Systems Exam With Actual Questions
& Verified Answers,Plus
Rationales/Expert Verified For
Guaranteed Pass /2026 /Latest
Update/Instant Download Pdf
1. Which NFPA 90A section requires that air ducts be constructed
of noncombustible materials in certain occupancies?
A. Section 4.1
B. Section 5.2
C. Section 6.3
D. Section 7.4
B. Section 5.2
Rationale: Section 5.2 of NFPA 90A specifies that air ducts in certain
high-hazard or special occupancy applications must be constructed
of noncombustible materials to reduce fire spread.
2. What is the maximum permitted flame spread index for duct
linings in commercial buildings?
A. 25
B. 50
C. 75
D. 100
,B. 50
Rationale: NFPA 90A limits flame spread index to 25 or 50 for duct
linings depending on occupancy and location, ensuring reduced fire
propagation through HVAC systems.
3. Where are smoke detectors required in air-handling systems
according to NFPA 90A?
A. Only in return air ducts
B. Only in supply air ducts
C. In both supply and return air systems serving certain
occupancies
D. Not required in air-handling systems
C. In both supply and return air systems serving certain occupancies
Rationale: NFPA 90A mandates smoke detectors in both supply and
return ducts in certain occupancies to detect smoke early and
prevent system spread.
4. Which type of air duct joint is prohibited in smoke control
systems?
A. Welded
B. Riveted
C. Butt seam with gasket
D. All welded
B. Riveted
Rationale: Riveted duct joints are prohibited in smoke control
systems due to the potential for leakage; welded or properly sealed
joints are required.
5. NFPA 90A requires fire dampers in which location?
A. Supply ducts in office buildings
B. Ducts penetrating fire-resistance-rated assemblies
, C. Return air ducts only
D. Roof exhaust ducts
B. Ducts penetrating fire-resistance-rated assemblies
Rationale: Fire dampers are required where ducts penetrate walls,
floors, or partitions with a fire-resistance rating to maintain
compartmentation.
6. What is the minimum fire-resistance rating for a fire damper
assembly in a 2-hour rated wall?
A. 20 minutes
B. 45 minutes
C. 1 hour
D. 2 hours
C. 1 hour
Rationale: NFPA 90A requires fire dampers to have a rating at least
equal to the fire-resistance rating of the wall or floor penetration.
For a 2-hour wall, a 1-hour damper is typically acceptable if tested
accordingly.
7. NFPA 90A specifies that smoke dampers must close under
which conditions?
A. Only during a fire
B. When air velocity exceeds 2000 fpm
C. Upon actuation of smoke detection system
D. When the HVAC system shuts down manually
C. Upon actuation of smoke detection system
Rationale: Smoke dampers are linked to smoke detectors and close
automatically to prevent the spread of smoke through ducts.
8. What is the minimum clearance required around fire dampers
installed in walls?
, A. 1 inch
B. 2 inches
C. 3 inches
D. 4 inches
B. 2 inches
Rationale: NFPA 90A requires a minimum of 2-inch clearance
around dampers to ensure proper operation and avoid obstruction.
9. Which material is generally prohibited for interior duct lining in
most commercial HVAC systems?
A. Fiberglass
B. Mineral wool
C. Combustible material
D. Metal mesh
C. Combustible material
Rationale: Combustible duct materials can increase fire propagation
risk; NFPA 90A limits combustible materials in duct interiors.
10. How often must fire dampers be inspected and tested
according to NFPA 90A?
A. Annually
B. Every 2 years
C. Every 5 years
D. Only after installation
A. Annually
Rationale: NFPA 90A and NFPA 80 require annual inspection and
operational testing of fire dampers to ensure proper function.
11. What is the primary purpose of an HVAC smoke control
system?
A. Cooling supply
