Operations Exam Practice Questions And

FDNY G42 Use of Liquefied Petroleum Gas or Compressed Natural Gas For All Roofing Operations Exam Practice Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

• What does the G42 certification primarily regulate during roofing

operations?

• Use of electric tools
• Use of diesel generators
• Use of LPG or CNG fuel systems
• Use of tar

Rationale: G42 specifically governs the use of LPG and CNG during

roofing operations.

• Who is responsible for ensuring fuels are stored properly on a job site?
• General contractor 1 / 4

• Certificate of Fitness holder
• Property owner
• FDNY inspector

Rationale: Only the certified operator has the regulatory

responsibility during active operations.

• When using LPG on a roof, what is the minimum distance from the

edge it must be kept?

• 1 foot
• 2 feet
• 3 feet
• 6 feet

Rationale: Positioning cylinders at least 3 feet inside roof perimeter

prevents accidental falls and damage.

• Which cylinder type is allowed for roofing torch operations?
• Horizontal only
• DOT-approved cylinders
• Refillable commercial propane tanks
• Steel drums

Rationale: FDNY requires standardized approved cylinders for safety

and uniform handling.

• What is the appropriate method for leak testing LPG fittings?
• Using a lighter
• Smelling only 2 / 4

• Soap solution
• Shaking the cylinder

Rationale: Soap solution reveals leaks visually via bubble formation

and is mandated as safe.

6. LPG is heavier than air and tends to:

• Rise upward
• Sink and accumulate in low spots
• Evaporate quickly
• Neutralize naturally

Rationale: LPG gas sinks and can collect in depressions creating

explosion hazards.

7. CNG is primarily composed of:

• Butane
• Methane
• Propylene
• Hexane

Rationale: Compressed Natural Gas is chiefly methane, making its

behavior different from LPG.

• What type of fire extinguisher must be near roofing LPG/CNG

operations?

• Class A only
• Class C only
• 3-A:40-B:C rated extinguisher 3 / 4

• Water only

Rationale: This extinguisher rating covers both gas and liquid fuel

fires.

9. Cylinders should be transported:

• Horizontally
• Upright and secured
• Tilted at 45 degrees
• Loose and unsecured

Rationale: Vertical secure position reduces risk of valve damage and

leaks.

• LPG cylinders must be stored at least how far from ignition

sources?

• 3 ft
• 5 ft
• 10 ft
• 15 ft

Rationale: Storing cylinders a minimum of 10 feet from flames

prevents accidental ignition.

• Which valve must be shut off first when stopping torch work?
• Torch head valve
• Cylinder valve
• Regulator valve
• / 4