CES Blast Effects & Damage Assessment 2

Question 1

What is the term for the secondary phase of a blast wave where air pressure drops below ambient atmospheric pressure?

Accepted Answer

Negative phase

Answer

The negative phase (suction phase) follows the positive phase and can cause structures to be pulled outward after the initial push.

Question 2

Which factor MOST significantly increases the scaled distance when assessing blast damage potential?

Accepted Answer

Increased standoff distance

Answer

Scaled distance (Z = R / W^(1/3)) increases as standoff distance R increases, indicating lower blast damage potential.

Question 3

A structure experiencing 'progressive collapse' after a blast has failed primarily due to which mechanism?

Accepted Answer

Loss of load-bearing columns removing support for upper floors

Answer

Progressive collapse occurs when the loss of key load-bearing members causes successive floor failures in a chain reaction.

Question 4

In the context of explosion injuries, which organ system is MOST vulnerable to primary blast injury?

Accepted Answer

Air-containing organs (lungs, GI tract, ears)

Answer

Primary blast injury results from the pressure wave acting on gas-filled organs, with the lungs and eardrums being most susceptible.

Question 5

What does the 'impulse' of a blast wave measure?

Accepted Answer

The area under the pressure-time curve

Answer

Impulse is the integral of overpressure over time and determines the total force imparted to a structure or body.

(CES) Certified Explosives Specialist Practice Test