Operations Exam Practice Questions And

FDNY G36 Use of Liquefied Petroleum Gas or Compressed Natural Gas in Manhole Operations Exam Practice Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

• What is the primary purpose of the G36 certification?

To ensure safe use of LPG or CNG during manhole operations

Rationale: Certification ensures personnel are trained to safely use

gas fuels underground.

• Which gas is heavier than air and tends to settle in low areas?

Propane (LPG)

Rationale: LPG is heavier than air while CNG is lighter.

• Which gas is lighter than air and rises when released?

Compressed Natural Gas (CNG) 1 / 3

Rationale: CNG is composed of methane, which rises instead of

pooling.

• Who must be present on site during LPG or CNG operations in

manholes?A G36 Certificate of Fitness holder

Rationale: FDNY requires a certified operator at all times.

• Which document must be available on location during operations?

The G36 certificate and ID of the holder

Rationale: Proof of certification is required at job site.

• What type of ventilation is required before entering a manhole?

Forced mechanical ventilation

Rationale: Ensures removal of combustible gas buildup before entry.

7. LPG cylinders must be stored:

In an upright position

Rationale: Vertical storage prevents liquid from contacting the relief

valve.

• What color is typically associated with LPG cylinders?

Silver or light gray

Rationale: These reflective colors minimize heat absorption.

9. Before lighting equipment with LPG underground, you must first:

Check for combustible gas accumulation Rationale: Ignition without checking could trigger an explosion. 2 / 3

• Which detection instrument is used to measure gas

concentration?Combustible Gas Detector

Rationale: Used to verify gas levels below flammable thresholds.

11. The Lower Explosive Limit (LEL) of natural gas is approximately:

5%

Rationale: Concentrations below 5% cannot sustain combustion.

12. If LEL exceeds safe limits, operations should:

Stop immediately and ventilate

Rationale: Continuing work risks ignition and explosion.

• LPG cylinders in use must be at least how far from ignition

sources?10 feet

Rationale: Required separation reduces ignition risk.

14. Regulators used on LPG systems must be:

Approved for LPG use

Rationale: Incorrect regulators can cause pressure failures.

15. During transportation, LPG tanks must be:

Secured to prevent tipping

Rationale: Prevents damage and valve impact.

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