Explosion Hazards Case Studies

In the list below, select the liquid materials normally stored under pressure that have atmospheric boiling points well below ambient temperatures.

-Carbon Dioxide -Refrigerants -Ammonia

Which of the following statements is/are true regarding the Imperial Sugar Company incident?

-Emergency evac plans were inadequate-Airborne combustible sugar dust accumulated above the minimum explosible concentration inside the newly enclosed steel belt assembly.-Inadequate housekeeping practices resulted in significant accumulations of combustible sugar dust.

What is the name of the test typically used to characterize combustion behavior of both vapor-air mixtures and dust-air mixtures?

20 liter sphere test

An explosion always consists of what components?

A blast wave & an energy release

What hazards can contribute to the damage and injury caused by explosions?

All choices

How can toxic materials in a process subjected to an explosion be released?

All of the above

Pressure vessel burst scenarios can involve

All of the above: -Fabrication -Pressurization -External Sources -Mechanical

A sudden loss of containments

BLEVE

The change in momentum of a blast is known as the:

Blast impulse

Which type of explosion can result in missiles being projected

Both explosions

Which European standard focuses on dust explosion venting protective systems?

CEN EN 14491

The combustion of dust in air is most commonly a

Deflagration, I think

T or F: The six spherical storage tanks and 48 smaller horizontal cylindrical tanks all exploded instantaneously at the Mexico City LPG terminal.

False

What three elements of the dust explosion pentagon shown here are missing

Heat Confinement and Dispersion

by reducing the oxidant concentration, we can change the ____ and in turn reduce the flammable region

I think its upper flammability limit. its not LOC

A dust explosion requires a suspended cloud of combustible particulates at a concentration above the ____.

MEC

Which of the following resources is best for understanding explosion vent sizing and design criteria?

NEPA 68

Which U.S. recommended practice provides criteria to determine ignitability hazards in chemical process areas using flammable liquids, gases, or vapors?

NFPA 497

the combustion process illustrated here represents a ____ because the reaction front moves at a speed less than the speed of sound in the unreacted gases.

Not "controlled chemical reaction"

Which of the following elements appear on both the dust explosion pentagon and he fire triangle

Oxygen Heat Fuel

In a shock wave, the max pressure over ambient conditions ins called the:

Peak Overpressure

Combustible dusts, mists and aerosols, VCEs, and condensed phase explosions are examples of___.

Propagating reactions

___ are those where the reaction starts within a volume of reactants under suitable conditions of temperature, pressure, and concentration and rapidly progresses through that reactant volume in a defined "reaction front"

Propagating reactions

Factors that need to be considered to determine the distance a fragment could travel in an explosion include fragment:

Shape Trajectory and Mass

A discontinuous change in gas density, pressure, and velocity of the air surrounding an explosion point is known as a:

Shock wave

When measuring blast wave pressure, if the pressure transducer is at right angles to the blast wave, the overpressure measured is called the

Side-on overpressure

T or F: The minimum ignition energy of a material is difficult to characterize and is highly dependent on the experimental configuration.

T

What is the danger associated with systems that operate above the upper flammability limit (UFL)?

The introduction of oxidants that could generate a flammable mixture

A boiling liquid expanding vapor explosion (BLEVE) has the potential for projecting missiles great distances because of:

The large amount of energy released during these incidents

Flux multiplied by exposure time is know as

Thermal dose

Combustible liquid aerosols can lead to deflagrations

True

T or F: It is generally considered impractical to eliminate all possible ignition sources in a process facility

True

T or F: The fundamental burning velocity is the highest achievable value that is obtained in a quiescent environment.

True

The higher the impulse associated with the blast wave, the greater potential for damage

True

The rapid discharge of flammable process material through a relief system may result in a VCE

True

What type of explosion occurred in the incident at the BP Texas City refinery?

Vapor Cloud Explosion

The ___ is the lowest temperature at which a fuel-oxidant mixture will spontaneously ignite under specified test conditions.

autoignition temperature

VCEs usually occur due to the loss of

containment

The AIT of a mixture generally ____ with increased oxygen concentration.

decreases

the AIT of a mixture generally ____ as the pressure increase

decreases

For flammable gases in air, the minimum ignition energy (MIE) increases as the fuel concentration _________ from the concentration corresponding to the lowest MIE value.

either increases or decreases

damage-limiting construction

false

Unlike ____, which allows the static charge to drain away, ____ equalizes the potential charges but does not eliminate the static charge

grounding/\bonding

The AIT of a mixture generally ____ as mixture becomes either rich or lean

increases

Which of the following should not be permitted to operate in areas where flammable materials might be present?

maybe all of them?

Among other safety measures, explosives manufacturer facilities often use ___ and separation distance to prevent shock ignition of explosive material in neighboring building.

minimization

Which letter on this diagram best represents the flammable region

pink area

a gradual change in the gas density, pressure, and velocity of the air surrounding an explosion point is known as a

pressure wave

When measuring blast wave pressure, if the pressure transducer is at right angles to the blast wave, the overpressure measured is called the:

side on overpressure

In which ways can ignition be achieved in the 20 liter sphere test?

spark, chemical igniter, exploding fuse wire, hot wire

True or false: When flammable vapor is confined within a vessel and that vapor is ignited, the resulting deflagration could cause a pressure vessel burst.

true

the minimum ignition energy for combustible dusts as a group are generally higher then that of a flammable gases, everything else being equal

true

DDTs occur most frequently

within pipelines