Explosives Exam Practice Questions And

FDNY E12 Demolition of Building Using Explosives Exam Practice Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

• What is the primary objective in a controlled demolition of a building?

a) Minimize the cost of demolition

b) Maximize the debris spread

c) Ensure the safety of personnel and surrounding property

d) Complete demolition as quickly as possible

Rationale: The main priority in controlled demolition is safety, protecting

both personnel and nearby structures from harm.

• Which type of explosive is commonly used in building demolition?

a) Dynamite

b) Gunpowder 1 / 4

c) Emulsion explosives

d) Black powder

Rationale: Emulsion explosives are preferred due to their stability, ease of

handling, and controlled detonation properties.

• What is the role of a blast pattern in building demolition?

a) To determine debris disposal methods

b) To calculate project costs

c) To ensure the building falls in a predetermined manner

d) To select personnel

Rationale: The blast pattern is carefully designed so the building collapses

safely within the intended area.

• Before detonating explosives, what is the most important step?

a) Selecting the type of explosives

b) Clearing all personnel and the public from the danger zone

c) Measuring the building height

d) Calculating the weight of debris

Rationale: Safety protocols mandate clearing everyone from the blast zone

to prevent injuries.

• What is the minimum safe distance for observers during a controlled

demolition?

• 50 feet
• 100 feet 2 / 4

c) At least 500 feet or as determined by the demolition plan

• 250 feet

Rationale: The safe distance depends on building size and explosives used,

generally at least 500 feet.

• Why are delay detonators used in building demolition?

a) To reduce explosive cost

b) To control the sequence of collapse

c) To increase debris spread

d) To simplify placement

Rationale: Delays allow controlled timing between charges, directing the

building to fall as planned.

• What is a “load calculation” in demolition?

a) Estimating debris weight

b) Measuring building height

c) Determining the amount of explosive required for each structural

element

d) Calculating labor needs

Rationale: Load calculations ensure enough explosives are used to bring

down the structure without excess.

• What is the main hazard of using improper charge placement?

a) Increased labor cost

b) Uncontrolled building collapse 3 / 4

c) Excessive sound

d) Slow debris removal

Rationale: Incorrect placement can cause parts of the building to fall

unpredictably, endangering lives.

• Which professional is required to approve a demolition plan in New

York City?

a) Project manager

b) FDNY explosives officer

c) General contractor

d) Structural engineer

Rationale: The FDNY regulates and approves all explosive demolition plans

for safety compliance.

• What is “cratering” in building demolition?

a) Using explosives to create holes in debris

b) Intentional creation of a cavity to control building collapse

c) Removing the roof before demolition

d) Tunneling under foundations

Rationale: Cratering helps direct the collapse inward, reducing risk to

surroundings.

• How should explosives be transported to the demolition site?

a) In personal vehicles

b) Using approved, secure transport containers

• / 4