Fundamentals & Core Principles Flashcards
7 cards from real CES practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Fundamentals & Core Principles flashcards as text
Under 27 CFR Part 555, how long must a Federal Explosives Licensee retain acquisition and disposition records?
Answer: 5 years
ATF regulations at 27 CFR § 555.121–555.128 require licensees and permittees to retain all acquisition and disposition records for five years.
What is the purpose of a 'delay element' in a blasting cap or detonator?
Answer: To introduce a time interval between circuit firing and detonation to sequence multiple holes
Delay elements allow sequential detonation of individual holes, reducing peak vibration, improving fragmentation, and controlling burden movement.
Which standardized test is used in the U.S. to determine whether an explosive is cap-sensitive?
Answer: No. 8 test cap test
The No. 8 test cap test determines cap sensitivity by firing a standard No. 8 electric blasting cap into an unconfined sample of the explosive.
What is the main hazard associated with ammonium nitrate when it is contaminated with fuel oil or organic material and exposed to extreme heat?
Answer: It can undergo self-sustaining decomposition or detonation even without a conventional initiator
Contaminated ammonium nitrate under confinement and heat can undergo runaway exothermic decomposition, potentially transitioning to detonation as demonstrated in historical disasters.
In explosives chemistry, what does 'heat of explosion' measure?
Answer: The energy released per unit mass during the detonation reaction
Heat of explosion (kJ/kg) is the total thermochemical energy released per unit mass when an explosive undergoes complete detonation under adiabatic conditions.
What condition is described as a 'hangfire' in blasting operations?
Answer: A delayed or hesitant initiation where detonation occurs after an unpredictable time lag following circuit firing
A hangfire is an unpredictable delay between energizing the blasting circuit and actual detonation, which creates extreme danger for anyone who approaches the hole.
Which UN hazard classification number is assigned to Division 1.1 explosives?
Answer: The UN number varies by specific explosive, but Division 1.1 indicates mass explosion hazard
Division 1.1 is a DOT/UN compatibility group designation indicating a mass explosion hazard; the specific UN number (e.g., UN 0081 for blasting explosives) depends on the exact substance.