A-1-1-4 Ch 2-3 Flashcards
What poses an unacceptable risk during intentional detonations?
Insufficient or lack of measures that protect personnel and engineering controls intended to mitigate explosion effects.
What protection must be afforded to personnel before AE detonation?
Adequate frontal and overhead protection against explosion effects.
What should personnel avoid during emergency responses near AE detonation?
Remain away from exterior walls and windows and avoid potential explosion site (PES) direct viewing.
What are ‘rogue’ fragments?
AE features such as noses, nose plugs, suspension lugs, strongbacks, and baseplates that can be projected to distances greater than 10,000 feet (3,048 meters).
What are some engineering fragment control techniques?
- Orienting AE away from personnel
- Surface barricading
- Open pit or buried (tamped) detonations
What can result from the intentional detonation of cased or uncased AE propellants?
A significant propellant-contributing mass detonating response.
What factors can enhance explosion effects?
- Case material and thickness
- Method of initiation
- Point-of-initiation
- Charge geometry
What are accidental detonation protective measures?
Measures that mitigate potential accidental explosion effects.
What should be done if a camouflet is accidentally opened?
Excavate and/or backfill it with heavy equipment to prevent collapse.
What should be increased for the intentional detonation of AE with preformed/scored fragmenting warheads?
Minimal fragmentation distances.
What happens when stacked AE is detonated?
It can project fragments to greater distances than multiple items arranged side-by-side.
What is the effect of non-design modes of AE initiation?
It can create larger primary case fragments that project greater distances.
What is an explosion?
A transformation of a substance accompanied by a rapid transition of potential energy into mechanical work.
Define a chemical explosion.
A reaction where atomic nuclei maintain their identities, generating high temperatures and large quantities of gas, producing a blast wave.
What distinguishes an atomic/nuclear explosion from a chemical explosion?
It emits energy quantities per unit mass of reactant from a million to a billion times those available from chemical explosives.
What characterizes a mechanical explosion?
Pressure gradually increases within a sealed container until it fails, such as in a steam boiler explosion.
What is the definition of an explosion in terms of energetic material?
The ignition and rapid burning of energetic material leading to high local pressure and a propagating shock wave.
How does detonation differ from an explosion?
Detonation is a violent chemical reaction that propagates at supersonic velocity, producing intense shock waves and high pressures. Detonation is a type of explosion.
What is a deflagration?
The ignition and rapid burning of confined energetic materials leading to non-violent pressure release.
What occurs during a deflagration to detonation (DDT) transition?
Energy transformation changes from a slow process to a supersonic process.
What is a low-order detonation?
An explosive filler reaction slower than a high-order detonation, usually considered less than 8,200 feet-per-second.
What can damage to AE energetic materials lead to?
Energetic material crystal anomalies and potentially spontaneous ignition.
What is the initial formation of a blast wave?
A shock wave traveling through the material, forming a compact volume of high pressure gases.
What happens to the shock front as it travels outward?
It decays in strength, lengthens in duration, and slows down approaching local sonic velocity.
What is the region of under pressure created by a blast wave called?
Rarefaction.
What characterizes the positive phase duration in blast wave pressure?
The rise to peak incident pressure followed by decay to ambient pressure
This phase occurs after the shock front arrives at a given location.
What is the negative phase duration in blast wave pressure?
Usually much longer than the positive phase, characterized by negative pressure and particle flow reversal
This phase follows the positive phase duration.
What tools are used to record characteristic pressure and time history relationships in blast waves?
Pressure transducers
They measure the pressure changes over time during a blast event.
How is a deflagration pressure time record characterized?
Shows a slow increase of pressure and fluid velocity in the region preceding the flame front
This occurs even at low flame speeds.
What is the typical peak pressure achieved in an enclosure with a hydrocarbon-air mixture?
Approximately 116 psi (800 kPa)
This pressure is sufficient for most buildings to fail.
What peak pressures are assumed for an enclosed hydrocarbon-oxygen environment?
About 232 psi (1,600 kPa)
These pressures are significantly higher than those in hydrocarbon-air mixtures.
How does pressure buildup in deflagrations compare to that in detonations?
Occurs even at low flame speeds and remains at an obtained level due to fixed volume
This can lead to longer positive phase durations in deflagrations.
What is the difference in initial overpressures between vapor cloud explosions and solid high-explosive detonations?
Vapor cloud explosions tend to have lower initial overpressures but higher impulse at greater distances
This is due to differences in density and volume between the two types of explosions.
What factors affect pressure buildup in an enclosed environment?
Flame propagation and degree of confinement
These factors determine how pressure develops during an explosion.
Fill in the blank: The negative phase in blast wave pressure is characterized by _______.
negative pressure and particle flow reversal
What is the most widely used approach to blast wave scaling?
Cube-root-scaling
Formulated by Hopkinson (1915) and independently verified by Cranz (1926)
What does the cube-root-scaling law state?
Self-similar blast waves are produced at identical scaled distances when two explosive charges of similar geometry and of the same explosive, but of different sizes are detonated in the same atmosphere.
What is the formula commonly used in blast wave scaling?
D = K*W^1/3
In the formula D = K*W^1/3, what does ‘D’ represent?
Distance in feet
In the formula D = K*W^1/3, what does ‘W’ represent?
Net explosive weight (NEW) or net explosive weight for quantity distance (NEWQD)
What is the recommended practice for minimum separation distance calculations for intentional detonations?
Include the net high-explosive weight (HEW) and/or net propellant weight (NPW) trinitrotoluene (TNT) equivalent explosive weights.
What is the symbol ‘Q’ used for in metric units?
Net Explosive Quantity (NEQ) in kilograms
In the formula D (meters) = Km*Q^1/3, what does ‘D’ represent?
Distance in meters
What are the units of the K-factor in English and metric systems?
- English system: ft/lb^1/3
- Metric system: m/kg^1/3
How does the value of ‘K’ in English units compare to ‘Km’ in metric units?
K in English units is approximately 2.52 times Km in metric units.
What does the terminology K9, K11, K18 refer to?
Specific values of K, meaning K = 9, K = 11, and K = 18.
What factors can affect the scaling of blast overpressure?
- Explosive composition (ideal vs non-ideal)
- Surface or airburst
- Charge geometry
- Bare or cased charge
- Point(s)-of-initiation
True or False: The cube-root scaling law always applies to all types of explosives.
False
What tool can be used to calculate many blast wave parameters?
DDESB Blast Effects Computer (BEC)
Where can the Blast Effects Computer (BEC) be accessed?
AEODPS resources disc, SIPR and NIPR JEOD Portals
Fill in the blank: The NEWQD for the purpose of this manual is equal to the _______.
Net high-explosive weight (HEW)
What is the Equivalent Explosive Weight (EEW)?
The weight of a standard explosive (usually TNT) required to produce a shock front of equal magnitude
EEW is commonly referred to as the TNT equivalent or relative effectiveness of an explosive material.
What are the two most common types of equivalencies for EEW?
- Peak pressure
- Positive impulse
What is the typical pressure range over which EEW equivalency data is averaged?
0.50 to 10 psi (3.45 to 68.95 kPa) or greater
What factors must be the same when determining EEW equivalency?
- Test and standard charge geometries
- Charge orientation to the surface
- Points of initiation
How is data adjusted if testing is done at different atmospheric pressures or temperatures?
Data is scaled to a common basis before any equivalency determination is made.
What is the effect of charge geometry on EEW?
Rearranging an explosive charge geometry to a cylinder can enhance blast parameters by a factor of up to 15.
How much can a cylindrical explosive charge weight be reduced compared to a hemispherical configured charge?
By over 50 percent
What factors can enhance blast effects in cylindrical and box-like charge geometries?
- Shock waves do not enter surrounding air simultaneously
- Presence of an extensive reflecting surface
- Generation of secondary shock wave amplitudes
What is the typical range of length-to-diameter (L/D) ratios for bomb and projectile warheads?
Ranges from about 6-1 to 5-1, to about 3-1 respectively
What types of geometries are typically encountered by EOD?
- Pancake shapes
- Cylindrical geometries
What is the L/D ratio range for pancake shapes like landmines?
Ranges from 1/2 to 1/4
What phenomena occurs during a spherical charge explosion?
Creation of primary shock, reflected wave front, slip line, triple point, and Mach stem
What is the significance of the triple point in a blast wave?
It creates an upward moving path and affects the strength of the Mach front.
How does surface type affect the reflective wave strength during an explosion?
Non-yielding surfaces cause stronger reflective waves than yielding surfaces.
What environmental conditions can influence the reflective wave?
- Surface air density
- Temperature
- Snow-cover
Fill in the blank: The enhancing effect of charge geometry has been verified with _______.
[high-explosives]
True or False: Charge geometry does not impact the design of IEDs.
False
What are the blast parameters for cased AE compared to uncased explosives?
They are different and become functions of multiple variables rather than just distance and charge weight.
Variables include case weight, case material properties (toughness, density, case thickness), and geometry.
How do light-cased explosives compare to heavier-cased AE in terms of EEWs?
Light-cased explosives tend to create greater EEWs than bare charge or heavier-cased AE.
EEWs refer to effective explosive weights.
What is the relationship between heavy-cased AE and fragment sizes?
Heavy-cased AE tend to break up into larger fragments with greater throw distances than light-cased AE.
Larger fragments can increase the hazard due to greater impact distances.
What additional impulse is associated with the impact of the case’s fragments?
There is an impulse associated with the impact of the case’s fragments on any surface.
This impulse adds to the air blast impulse.
What are the combined effects of fragments and blast in cased AE?
They create a more severe hazard than either the individual fragment impact loads or the air blast loads alone.
This highlights the importance of considering both effects in safety assessments.
Fill in the blank: Light-cased explosives tend to create greater _______ as opposed to bare charge or heavier-cased AE.
EEWs
EEWs stands for effective explosive weights.
True or False: The case material properties do not affect the blast parameters of cased AE.
False
Case material properties such as toughness and density significantly influence blast behavior.
What factors are included in the blast parameters of cased AE?
- Case weight
- Case material properties (toughness, density, case thickness)
- Geometry
These factors alter the expected performance of the explosive.
What are the two primary blast load parameters for determining damage consequences?
Peak pressure and impulse
Peak pressure is the highest pressure increase at the shock front. Impulse is the area under the positive phase of the pressure-time curve.
How is peak pressure typically measured?
In psi or kPa
Peak pressure is a critical factor in assessing blast damage.
What is impulse expressed in for English units?
Pounds-per-square-inch-milliseconds (psi-ms)
In metric units, impulse is expressed in kilopascals-milliseconds (kPa-ms).
Why is impulse an important aspect of damage-causing ability?
Because the damage response depends on the duration the force is applied
Longer duration of force application can lead to greater damage.
What must peak pressure and impulse exceed to cause damage?
Certain minimum values
These values must overcome exposure integrity and resistance.
What factors can make exposure damage response difficult to predict?
Variations in peak pressure, charge weight, and distance from the potential explosion site (PES)
These factors affect how a structure responds to blast loads.
What do Pressure-Impulse (P-I) diagrams represent?
They are generated for specific structures based on construction material, size, and supporting framework
Different materials will have different P-I diagrams.
What is the shape of the relationship between damage and P-I values?
Quasi-hyperbolic curves
These curves describe the threshold for exposure damage.
What happens to damage response as P-I values near the 0 percent curve?
Damage response lessens
There is a limit at which an explosive charge can produce damage.
For smaller charge weights, what primarily causes damage?
High peak pressure loading
This is observed on the left side of the damage curve.
What primarily causes damage for large charge weights?
High impulse loading
This is observed on the right side of the damage curve.
What type of structure requires high peak pressure but low impulse for demolition?
Strong but lightweight structures
These structures require a specific balance of pressure and impulse.
What is the wall response for a 1.25-pound explosive charge detonated at a K5 scaled distance?
Peak incident overpressure of about 24 psi, a 1.7 millisecond positive phase duration, and an impulse of 16.3 psi-ms
The wall may experience little or no displacement and localized damage.
What is the wall response for a 4,500-pound explosive charge detonated at a K5 scaled distance?
Greater damage due to a longer 25 millisecond positive phase duration and an impulse of 254 psi-ms
The larger charge covers the wall face more completely than the smaller charge.
What occurs when the shock wave impinges a rigid surface at an angle?
A reflected pressure wave is instantly developed on the impinged surface
The reflected pressure is influenced by the incident pressure wave and the angle of impact.
What factors can affect the reflected incident wave?
Factors include:
* Ground surface composition
* Irregular ground/terrain surfaces
* Atmospheric conditions
* Structures/objects impacted by the wave
Energy may be dissipated into the ground, affecting the reflection.
What is normal reflection?
Normal reflection occurs when the peak incident wave impinges on the face of an unyielding surface
The reflected pressures can vary significantly.
How much can reflected pressures vary from the peak incident wave in normal reflection?
Reflected pressures may vary from two to nine times greater than the peak incident wave
This can lead to significant injury or death for personnel nearby.
What happens to windows and doors during a blast wave?
They will fail almost immediately (approximately 1 millisecond) after the onset of the shock front
Unless designed to resist applied overpressure loads.
What forms inside openings after a sudden release of high pressure?
A shock front forms inside of each opening
These fronts will expand and tend to combine into a single front.
How does the interior shock pressure compare to the incident pressure at the building’s exterior?
The interior shock is initially weaker than the incident pressure
However, the interior pressure strengthens due to reflections off interior walls and components.
What happens as the exterior blast wave continues to move forward?
It diffracts around the structure and forms trailing vortices
This affects the pressure distribution on the building.
What occurs to the pressure on the front face of the building after the blast wave passes?
The pressure drops rapidly to the sum of the initial ground-reflected incident wave overpressure
This results in similar pressures on the side and rear walls.
What type of waves sweep across the front face after the blast wave?
Rarefaction (low relative pressure) waves
These waves attenuate the initial reflected blast pressure.
What is the exposure after the passage of the shock front?
The exposure is immersed in a time-varying flow field
The dynamics of this flow field can affect structural integrity.
What phenomenon occurs when the detonation is above the ground surface?
Mach stem reflection
This occurs in scenarios such as air burst explosions.
What happens to the shock wave when it impinges on the ground surface?
It propagates outward along the ground surface.
What forms when the reflected wave combines with the incident wave?
A third wave called the Mach wave or stem.
What is the point where the incident wave, reflected wave, and Mach wave intersect called?
The triple point.
At the triple point, what are the conditions regarding peak pressure and impulse pressure?
Both are at the maximum and considerably higher than the original blast wave.
True or False: The peak pressure at the triple point is lower than that of the original blast wave.
False.
Fill in the blank: The Mach wave or stem has a _______ front at ground level.
vertical
What factors can enhance or focus blast waves?
Confinement, such as tunnels, corridors, trenches, or city streets
Blast waves decrease in intensity slower in confined spaces than in open areas.
How do weak blast waves resemble sound waves?
They are influenced by atmospheric conditions, such as temperature inversions
An atmospheric inversion can redirect weak blast waves downward, enhancing them.
In what ways do underground and underwater blast waves travel?
More like open-air blast waves than those under confinement
The speed and amplitude vary due to different densities of soil, water, and air.
What percentage of injuries are attributed to blast effects?
About 20 percent
Most injuries result from primary and/or secondary fragments or blunt trauma.
What factors influence injury from blast waves?
Duration of the positive phase, blast wave reflection, and dynamic pressures
Large explosive charges create significant blast wind.
How much greater are reflected blast waves compared to the initial incident shock wave?
Typically two to nine times greater
Reflected waves can significantly increase injury severity.
What is the injury risk for personnel in close proximity to reflecting surfaces?
Two to three times greater than if standing in the open
This applies when near surfaces like buildings.
What effect do enclosed explosions have on blast wave reflections?
Create multiple reflected complex blast waves
This increases the severity of injuries, especially near walls or corners.
What happens to blast waves in foxholes?
They create complex reverberation and static pressure effects
Personnel can experience greater and complex pressure loads.
How does the orientation of a person affect injury from blast waves?
Orientation towards the pressure front minimizes injury
Protective equipment can also influence injury severity.
What factors determine the severity of blast injuries?
Separation distance, person’s size, gender, and physical condition
Generally, closer proximity results in more severe injuries.
What is the casualty radius for auditory injury?
Assumes temporary hearing loss rather than eardrum rupture
Distances vary based on the type of body part affected.
Which body part is more sensitive to blast effects?
The larynx
It is more sensitive compared to the gastrointestinal tract and lungs.
What are blast effects related to?
Crushing incidents and/or reflected overpressures
Blast effects cause injuries due to the body’s inability to withstand rapid external loads.
What type of injuries are common manifestations of blast effects?
Injuries to the lung, GI tract, and upper respiratory tract
These injuries occur due to the rapid distortion of air-containing organs.
How do blast effects transmit stress to neighboring solid organs?
Through rapid distortion of air-containing organs
For example, contusions to the heart arise from strong stress waves developed in the lung.
What can large deformations of the body lead to?
Stresses in solid organs resulting in liver and spleen lacerations
Organs of different densities experience different rates of acceleration.
What systemic processes can be disrupted by rapid volumetric changes?
Systemic processes related to air emboli and pressure transients
Creation of air emboli can cause brain injury and cell death.
Which organs are the most sensitive to blast overpressure?
The ears
Ears frequently sustain injuries ranging from destruction of hairs to tympanic membrane rupture.
What types of hearing loss can occur due to blast effects?
Permanent hearing loss that is not medically treatable
Impaired hearing can lead to serious mistakes during training and combat.
What decibel level defines hazardous noise exposure during training or combat?
Greater than 84 dB for continuous noise and greater than 140 dB for impulsive noise
Hazardous noise exposure is common in military operations.
What is the effect of unprotected hazardous impulsive/impact noise?
Immediate hearing loss
Exposure to such noise can have serious consequences.
What do hearing protection devices have that indicates their effectiveness?
A noise reduction rating
This rating reflects the attenuation level in a laboratory setting.
How does field testing compare to laboratory testing for earplugs?
The reduction rating is approximately half that listed on the package
This discrepancy highlights the importance of real-world testing.
What additional protection is provided by combining noise muffs with ear plugs?
An additional 5 to 6 dB of protection
This combination enhances overall hearing protection.
What are the three groups of non-auditory body organs?
- Air-containing organs (larynx, trachea, lung, GI tract)
- Liver and spleen
- Kidneys, pancreas, and gallbladder
The air-containing organs are the most vulnerable and require the greatest concern for exposure.
Which organs show the first signs of injury at approximately the same blast intensity?
Air-containing organs (larynx, trachea, lung, GI tract)
These organs exhibit blast injury responses well below that seen in other groups.
What is the primary cause of lethality in blast injuries?
Multiple organ failure
All organs can be seriously injured at particular blast intensity.
What types of abdominal injuries are possible due to blast exposure?
- Bowel perforation
- Hemorrhage (small petechial to large hematomas)
- Mesenteric shear injuries
- Lacerations of solid organs
- Testicular rupture
Symptoms include abdominal pain, nausea, vomiting, and rectal pain.
What are common symptoms of abdominal injuries?
- Abdominal pain
- Nausea
- Vomiting
- Hematemesis
- Rectal pain
- Tenesmus
- Testicular pain
- Unexplained hypovolemia
These symptoms are similar to those of other abdominal injuries.
What factors influence lung damage response in blast injuries?
- Peak overpressure
- Impulse
- Proximity to reflecting surfaces
- Blast focus amplification
This amplification typically occurs as the blast wave passes through narrow openings.
How does the position of a person affect their exposure to blast reflection intensities?
Being on hands and knees or all fours increases exposure to floor blast reflection intensities
This is in contrast to being in an upright position.
What happens to lung damage as explosive charge weight increases?
Injury intensity increases, leading to higher lethality percentages
This occurs even when scaled distance (blast K-factor) and overpressure remain constant.
What is the consequence of lung damage reaching the circulatory system?
Air bubbles can enter the circulatory system, causing dangerous conditions
This can lead to suffocation, lung hemorrhage, and edema, often resulting in heart failure.
True or False: Lung damage is not sensitive to pressure-impulse.
False
Injury to the human body is pressure-impulse sensitive, similar to wall damage.
Fill in the blank: The most dangerous consequence of lung damage is __________.
suffocation from lung hemorrhage and edema
This condition can be fatal within a few minutes.
What are the two groups of traumatic brain injury (TBI)?
Penetrating traumatic brain injury (PTBI) and closed-head traumatic brain injury (CTBI)
TBI can be associated with all categories of blast-related injuries.
What characterizes penetrating traumatic brain injury (PTBI)?
A foreign object penetrates the skull and traverses through the brain tissue.
What causes closed-head traumatic brain injury (CTBI)?
Subsequent fall and/or impact with the ground or other non-yielding object or blunt impact to the head.
What symptoms can personnel experience after exposure to a blast?
Dazed, confused, or loss of consciousness.
What type of injuries does CTBI typically involve?
Injuries to the brain parenchyma, blood vessels, and fiber tracts.
What is blast-induced traumatic brain injury (BTBI)?
Injury to the brain caused by blast-induced forces resulting in significant accelerations and pressures within the skull.
What percentage of combat-related traumatic brain injuries is suspected to be caused by BTBI?
Nearly 70 percent.
How are mild BTBI cases characterized?
Brief loss of consciousness or awareness, typically less than 5 minutes.
What are common onset symptoms of mild BTBI?
- Headache
- Nausea
- Vomiting
- Dizziness
- Balance problems
- Fatigue
- Insomnia/sleep disturbances
- Drowsiness
- Sensitivity to light and noise
- Blurred vision
- Difficulty remembering
- Difficulty concentrating.
What emotional symptoms may a victim of BTBI experience?
- Emotional or personality changes
- Irritability
- Anxiety
- Depression.
What distinguishes moderate BTBI from mild BTBI?
Loss of consciousness between 30 minutes and 24 hours and/or neurological deficit.
What defines severe BTBI?
Prolonged loss of consciousness greater than 24 hours, often associated with significant neurological injury.
What are common neurological conditions caused by severe BTBI?
- Cerebral edema
- Neuroinflammation
- Vasospasm.
What physical effects can occur after exposure to blast overpressures between 25 to 34 psi?
Moderate to severe BTBI.
What are fragment-related injuries commonly associated with?
Penetrating injuries occurring in exposed areas like the head, neck, and extremities.
What type of injuries are most common from fragment-related injuries?
- Penetration of vital organs
- Blunt trauma
- Skull and bone fractures.
What is a significant cause of eye injuries among blast survivors?
Primary or secondary fragments, particularly glass.
What are tertiary effects in the context of blast injuries?
Injuries due to the displacement of the entire body by the blast wave followed by high deceleration impact loading.
What is the mortality rate when a person is thrown into a rigid structure at velocities greater than 26 feet-per-second?
About 50 percent.
What types of injuries are common in tertiary effects?
- Fractures
- Closed head injuries including PTBI, CTBI, and BTBI effects.
What are quaternary effects related to blast injuries?
All other blast-related effects such as burns and inhalation of energetic by-products.
What factors influence the structural and material blast response?
- Magnitude of the detonation
- Structure location relative to the PES
- Design and quality of construction.
How does the orientation of exposure affect damage response?
Blast pressures and impulses change quickly with small changes in standoff.
What is the difference in damage response between military AE and bulk non-cased explosive charges?
Military AE produces different damage responses compared to bulk non-cased explosive charges.
What is the significance of nuclear blast parameters in structural damage response?
Most structural and material blast damage responses data is based on nuclear blast parameters.
What does PPV stand for?
Peak Particle Velocity
How is particle velocity defined?
Oscillation or speed at which a particle moves back and forth
What is the maximum oscillation rate called?
PPV
What is the measurement unit for frequency?
Hertz (Hz)
In which units is maximum PPV oscillation normally measured?
Inch-per-seconds or feet-per-second
What are the three mutually perpendicular vibration wave directions?
- Transverse - horizontal motion at right angles to the blast
- Vertical - up and down motion
- Longitudinal or radial - horizontal motion in the axis between the blast and a recording location
How do PPV values propagate?
Spherically in all directions
What happens to particles as the oscillation rate diminishes?
Particles return to a rested state
What is the significance of PPV in terms of damage potential?
It is the single best descriptor and the most practical method for regulating damage potential to material and human response to ground shock vibration
What types of PPV values have been established?
- For structures
- For equipment
- For human tolerance
What do Tables 7 and 8 provide information about?
PPV values and expected effects for ground shock exposure and percentage of human complaints
True or False: PPV values are only relevant for human tolerance.
False
Fill in the blank: The number of times in 1 second that particles move is known as _______.
frequency
What factors determine the size and shape of an explosively-generated crater?
The quantity and type of explosive, the soil or rock medium, and the charge placement relative to the surface.
The relationship between these factors influences how effectively a crater is formed.
Which type of explosive is more effective in producing craters?
Lower detonation velocity explosives such as ammonium nitrate and fuel oil or ammonium dynamites.
Higher detonation velocity explosives like composition C-4 are less effective for crater formation.
How does the position of the charge affect crater formation?
The position relative to the air-ground interface determines energy partitioning.
Charges above the surface primarily release energy into the air, leading to minor craters.
What is the effect of an explosion occurring on or below the surface?
It is more effective in creating a crater due to direct energy to earth coupling.
This coupling allows more energy to be utilized in displacing soil or rock.
What is the optimum charge position for crater formation?
Between 0.5ft/lb^1/3 partially embedded into the surface to about 2ft/lb^1/3 below the surface.
This range maximizes crater effectiveness.
What are partial camouflets and how are they formed?
Partial camouflets are formed when an explosion occurs at scaled depths between 2.0ft/lb^1/3 and 3.5ft/lb^1/3.
They indicate a limited surface breach.
What characterizes full camouflets?
Full camouflets are formed at scaled depths greater than 3.5ft/lb^1/3 and have no surface breach.
This indicates that the explosion’s energy was contained effectively.
What is the face-on incident overpressure for a 50 percent probability of failure for small to large surface area windowpanes?
Between 0.87 to 0.087 psi
This refers to the pressure at which half of the tested windowpanes are expected to fail due to explosion overpressure.
What happens to fragment sizes as overpressure increases?
Fragment sizes tend to decrease
Higher overpressure results in smaller glass fragments being produced.
How does fragment spatial density change as you move away from the window?
Fragment spatial density decreases
The density is greatest directly behind the window and decreases with distance.
At what angle does the glass fragment density drop to approximately one-tenth of that measured directly behind the window?
At an angle of 20 degrees
This indicates how the distribution of glass fragments varies with angle.
What types of injuries are commonly associated with flying glass?
- Skin lacerations (penetration to approximately 3 millimeters or less)
- Puncture wounds (beyond 0.12 inch)
- Body-wall injuries (thorax and abdomen)
- Skull fractures
These injuries can vary in severity based on the size of the glass fragments and the blast overpressure.
How does blast overpressure affect the severity of injuries from flying glass?
Injuries increase with an increase in blast overpressure
Higher overpressure leads to more severe injuries due to the mass and velocity of fragments.
What is the significance of fragment mass in relation to injury severity?
A larger fragment can cause more serious injury than a smaller fragment
Heavier fragments can also translate further, increasing the risk of injury.
What can reduce the chances of injury from flying glass?
- Wearing light clothing
- Using typical window draperies and blinds
These measures can help mitigate the impact of flying glass fragments.
What are falling glass hazards?
Glass fragments falling from a height
Falling glass can cause serious injury or death depending on various factors, including mass and impact orientation.
What conditions can cause delayed effects from falling glass hazards?
- Windy conditions
- Secondary explosions
- Personnel movement
These factors can lead to loose glass fragments falling long after the initial explosion.
What is flyrock?
Debris propelled from a cave demolition site by explosion force
Flyrock poses a significant hazard due to its potential to cause injury.
What can flyrock be propelled at that increases the risk of injury?
High velocities and low angles
These conditions increase the likelihood of serious injuries to personnel without adequate protection.
At what blast scaled distances are falling glass hazards expected?
At K50 blast scaled distances
Falling glass hazards are unlikely at K328 scaled distances.
What are the injury types normally associated with flying glass?
Skin lacerations and penetration or puncture wounds
Skin lacerations penetrate approximately 3 millimeters or less, while puncture wounds exceed 3 millimeters but do not penetrate the abdomen and thorax.
What is the penetration measurement for thorax injuries caused by flying glass?
0.71 inches (18 millimeters)
This measurement refers to penetration between the ribs.
What is the penetration measurement for abdomen injuries from flying glass?
0.47 inch (12 millimeters)
Major organ injury is possible at this level of penetration.
What type of skull injury is related to flying glass?
Frontal (sinus area) skull fracture
This type of injury is specifically noted in the context of flying glass.
How does blast overpressure affect injuries from flying glass?
Injuries increase with an increase in blast overpressure
Overpressure also affects fragment mass and angle of impact.
What is the relationship between fragment mass and injury severity?
A larger fragment can cause a more serious injury than a smaller fragment at a given overpressure
For example, a 100-gram fragment is more dangerous than a 1-gram fragment.
What is the effect of fragment weight on translation distance?
Heavier fragments translate further than lighter fragments
This affects the potential impact area and severity of injuries.
How do larger and lighter fragments differ in their impact behavior?
Larger fragments result in a point-on impact; lighter fragments impact at random
This distinction is important for understanding injury patterns.
What clothing can reduce the chances of injury from flying glass?
Light clothing
Wearing light clothing can help mitigate injuries caused by flying glass.
What household items can reduce fragment velocities and translation distances?
Typical window draperies and blinds
These items can provide an additional layer of protection against flying glass.
What is Extremely Heavy-Cased AE?
An extreme subset of robust AE with specific weight criteria.
What is the ratio for Extremely Heavy-Cased AE?
The ratio of cylindrical empty case weight section to explosive weight is greater than nine.
What does AE stand for in this context?
Ammunition Explosive.
What is the formula used to calculate the ratio for Extremely Heavy-Cased AE?
Empty case weight divided by explosive weight.
Where can examples of Extremely Heavy-Cased AE be found?
In the DDESB fragmentation database.
True or False: Extremely Heavy-Cased AE is a subset of robust AE.
True.
Fill in the blank: The ratio for Extremely Heavy-Cased AE must be greater than _______.
nine.
What are the fragmentation characteristics when detonating multiple items in stacks compared to a single item?
Fragmentation characteristics differ; primary fragment masses may increase by as much as 50 percent and initial velocities may double.
Fragmentation characteristics are influenced by the orientation and arrangement of the explosives.
How does the total number of primary case fragments change when multiple items are detonated in stacks?
The total number of primary case fragments per item may decrease.
This is due to the interaction of the stacked items during detonation.
What effect do the sides and top areas of rectangular-shaped AE stacked have?
They contribute to greater far-field primary case fragment area densities.
This results from the geometry of the stacked explosives.
What is meant by non-design mode of initiation in stacked AE disposal?
It refers to the initiation of munitions in a stack by other munitions, rather than by the intended design mechanism.
This can lead to unpredictable detonation outcomes.
What is the typical assumption of non-design mode of AE initiation?
It assumes the munition is detonated by means other than its design mode, such as by a fuze and booster.
This can affect the performance and fragmentation of the explosive.
What increases in primary case fragment velocities and masses can occur in non-design mode of AE initiation?
Fragment velocities can increase by 25 percent and fragment masses can increase by up to 33 percent.
This results in different fragmentation dynamics compared to design mode initiation.
How can a primary case fragment achieve greater horizontal projection distances in non-design mode initiation?
By assuming a reduced drag configuration, allowing greater horizontal projection distances by 80 percent.
This is compared to a single round design mode of initiation.
What are some methods of non-design modes of initiation?
They include:
* Counter attacking the main primary case with a shaped charge
* Placing demolition blocks on a localized portion of a bomb case
* Burnout techniques
These methods lead to unintentional detonation effects.
What is the preferred method for placing explosive demolition charges in non-design mode initiation?
To place explosive demolition charges along the top of the entire length and covering the munition.
This helps suppress natural fragmentation dispersal.
Why should burnout techniques be considered a non-design mode of initiation?
Because the predictability of a complete burnout or the type of detonation (low-order vs high-order) cannot be assumed as absolute.
Burnout techniques may lead to unexpected outcomes.
What is a non-design mode of initiation when using a shaped charge?
A shaped charge impacting the secondary/main charge prior to impacting the booster is considered a non-design mode-of-initiation.
This can alter the expected detonation sequence.
What is the relationship between fuze/booster attacks and insensitive munition technology?
The fuze/booster attack is typically associated with advances in insensitive munition technology.
This technology aims to reduce the likelihood of accidental detonation.
What is an Exposed Site (ES)?
An ES is a location exposed to the potentially hazardous explosion effects from an explosion at a PES.
What determines the quantity of AE permitted at a PES?
The distance to a PES and the level of protection provided for an ES.
Define Potential Explosion Site (PES).
A PES is a location where an AE quantity will create a blast, fragment, thermal, and/or debris hazard in the event of an explosion.
What is Minimum Separation Distance (MSD)?
The minimum distance between a PES and an ES required to provide protection from AE explosion effects.
What do Quantity Distance (QD) Principles relate to?
The potential damage and/or injury and the minimum separation distance relationship between the PES and the ES.
What factors influence Quantity Distance?
- Explosive charge weight
- AE fragment category
- Protective personnel measures
- Engineering controls
What is Accidental Detonation?
AE hazards associated with an unplanned or unforeseen event.
What is required to establish accidental detonation QD?
An AE fragment category hazard and risk analysis.
Define Intentional Detonation.
AE hazards associated with a planned disposal or EOD procedure that may lead to a potential AE response event.
What analysis is required before a planned AE intentional burning or detonation?
An AE fragment category hazard and risk analysis.
What does Blast Overpressure Distance (BOD) relate to?
The peak blast overpressure portion of explosion effects.
What is Hazardous Fragment Distance (HFD)?
A calculated distance relationship equating to no more than one hazardous fragment per 600 square foot area.
What is the impact energy threshold for a hazardous fragment in HFD?
58 ft-lbs (79 joules) or greater.
What does Maximum Fragment Distance-Horizontal (MFD-H) refer to?
The distance to which primary case fragments from the PES are not expected to travel beyond the ES in the horizontal plane.
What is Maximum Fragment Distance-Vertical (MFD-V)?
The same as MFD-H except fragment projection is in the vertical or near vertical plane.
What does NEW for QD stand for?
Net Explosive Weight for Quantity Distance.
What is TNT EEW?
The weight of a standard explosive (usually TNT) required to produce a shock wave of equal magnitude.
What is the heat of detonation for TNT?
1,090 calories-per-gram (cal/gm).
What should be included in the NEW to obtain the NEWQD?
Energetic material having equivalencies greater than 100 percent.
True or False: The HFD assumes non-design mode of AE initiation.
False.
Fill in the blank: The equation to figure HFD from MFD-H for preformed/scored fragmentation warheads is _______.
[different from the equation used for naturally fragmented warheads]
What does AE stand for in the context of explosive safety?
AE stands for Ammunition and Explosives.
What factors influence the hazards and risks associated with an AE response?
Factors include:
* Type and amount of AE
* Type of explosive materials
* Item(s) designed means of initiation
What types of AE are considered in hazard analysis?
Types include:
* Conventional
* Chemical
* Improvised
What does NEWQD stand for in explosive safety?
NEWQD stands for Net Explosive Weight Quantity Distance.
What is the significance of weapon-specific fragment categories?
Fragment categories include:
* Non-robust
* Robust
* Extreme heavy-cased
What are the types of exposures at risk for AE?
Exposures include:
* Personnel
* Material
* Critical infrastructure
True or False: The potential AE enhanced explosion response effects must be considered when planning disposal procedures.
True
What is the purpose of identifying the PES and ES scope?
To determine the scope of an operation and identify exposures in relation to QD hazards.
What are some protective measures to reduce explosion effect outcomes?
Protective measures may include:
* Employing blast and fragment QDs
* Adjusting minimal separation distances
* Engineering controls for fragment projection
What should be determined whenever possible regarding AE?
The NEWQD and the composition and amount of explosive material involved.
Fill in the blank: Munition fillers that do not contribute to explosive effects, such as smokes and dyes, are ______ when determining NEWQD.
excluded
What is the basis for determining required QDs?
The basis includes:
* NEWQD
* Fragmentation distances
* HD types of the AE threat
What does HD stand for in the context of explosive safety?
HD stands for Hazard Division.
True or False: QD separation distances are measured along straight lines.
True
What should be disregarded when specifying QD separations for flight ranges of units?
Flight ranges in a propulsive state should be disregarded.
What is the greater QD derived for an AE threat?
The greater QD is derived from either blast overpressure or fragment.
What do the terms PES and ES refer to in AE response?
PES refers to Potential Exposure Site and ES refers to Exclusion Site.
What does MFD-H stand for?
Maximum Fragment Distance - High
MFD-H is associated with intentional detonations.
What does HFD stand for?
Minimum Fragment Distance - High
HFD is associated with accidental detonations.
How is MFD-H calculated?
By NEWQD of a single AE item and the applicable AE fragment category
NEWQD stands for Net Explosive Weight Quantity Distance.
What is the relationship between MFD-H and HFD?
MFD-H is associated with intentional detonations; HFD is for accidental detonations.
What measurement is used to determine MFD-H and HFD?
Outside diameter of a single AE item
The measurement is usually taken at right angles to the longer axis.
Which method usually yields the greater QD?
NEWQD method
It is recommended to calculate using both NEWQD and diameter when both are known.
What should be done for multiple like or mixed items?
Use the single item having the greatest QD by either NEWQD or diameter.
What is the risk of being less than derived MFD-H?
Increased risk to unprotected personnel from injurious and lethal primary case fragments.
What occurs if distances are less than HFD?
Increased fragment concentration per-square-foot area
This leads to a greater probability of fragment strike to unprotected personnel.
What should be referenced to determine the MFD-H versus NEWQD?
Base generic EQN 3-5 (Figure 27).
What is the significance of the outside diameter measurement?
It is used to calculate MFD-H and HFD for elongated items.
What does EOD incident response depend on?
Scenario dependency
What is the purpose of an accidental detonation scenario?
To provide a predicted or defined level of protection for unforeseen/unexpected AE events
What is an explosive area?
An area used for the handling, processing, and storing of AE
What determines the minimum QD and protective works applicable to AE explosion effects?
An onsite authority
Who typically assumes more risk in EOD scenarios?
Essential personnel
What should essential personnel have the ability to assess?
Unacceptable hazards and risks
What should be pre-established for essential personnel on a contingency basis?
Minimal safe separation QDs
What can justify a reduction in minimal separation distances?
Personnel protective structures and measures that mitigate explosion effects
What are BOD, MFD-H, and HFD QDs applicable to?
AE located on the surface, in the open, or in a structure or vehicle incapable of suppressing explosion effects
What is the BOD applicable for?
Blast effects
What types of threats does the MFD-H and HFD apply to?
IED threats consisting of military AE or reasonably characteristic military AE
True or False: The MFD-H and HFD methodologies are applicable to vehicle fragments.
False
What requires a hazard and risks analysis on a case-by-case basis?
Each threat
What should be employed whenever possible to mitigate AE explosion effects?
Pre-approved personnel protective structures and engineering controls
What should engineering controls intended to mitigate explosion effects be designed for?
The intended purpose
Fill in the blank: Accidental detonation minimal separation distances offer defined levels of protection to _______ in the event of an unforeseen event.
nonessential personnel
What is the risk of driving a stake into the surface over a buried UXO?
It could initiate UXO means-of-initiation or impact the UXO, causing detonation
What does HD stand for?
Hazard Division
What is assumed in fragmenting AE?
Explosive material is either totally or partially encased in non-pliable material
For nonessential personnel, what is the minimal K50 BOD for fragmenting AE?
K50 (Km19.84)
What type of explosives are associated with non-fragmenting AE?
Bare charge, paper or fiberboard wrapped, or pliable plastic packaged explosives
What emergency action should be taken if AE is involved in a fire?
Refer to emergency withdrawal distances
What is the minimal separation distance for nonessential personnel at K50?
Minimal K50 (Km19.84) BOD or the HFD, whichever QD provides the greater separation distance.
What types of buildings are not expected to sustain severe structural damage at the minimal separation distance?
Unstrengthened buildings such as wood frame, steel siding, or standard masonry.
What hazards are nonessential personnel protected from at the minimal separation distance?
Protection from exterior wall fragment perforation, interior wall spall, and flying/falling glass hazard effects.
What must personnel do if they take shelter in unstrengthened buildings at the HFD?
Remain away from exterior walls and glass windowpanes.
Who determines essential personnel?
Determined by onsite authority.
What does EOD stand for?
Explosive Ordnance Disposal.
What is the initial minimal separation distance for unspecified AE threats for nonessential personnel?
Minimal 1,250 feet (381 meters) separation distance; no direct viewing of AE threat location.
What is required for reducing a previously established maximum separation distance?
Onsite DoD or competent civilian authority approval.
What must be confirmed by an onsite EOD authority before reducing the separation distance?
Determined, beyond a reasonable doubt, that the risks are acceptable.
What is the minimal separation distance for nonessential personnel involved in mission critical intrusive activities?
Minimal K50 (Km19.84) BOD or HFD, whichever QD provides the greater separation distance.
What is the definition of stacked AE?
Refers to the arrangement of explosive ordnance that may affect separation distances.
What types of hazards are applicable to HD 1.3, 1.4, and 1.6 AE?
Accidental ignition/burning.
What equations are referenced for determining the minimal QD for HD 1.3 and HD 1.4 AE?
See EQN 3-13 and EQN 3-14.
What are the requirements for AE having a means-of-initiation?
Shall have appropriate external and/or internal safety features as required and in place.
What must happen after a successful completion of remote EOD render safe procedure?
Assessment of AE-specific explosion effect hazards and risks.
True or False: Essential personnel are fixed and cannot be determined by onsite authority.
False.
Fill in the blank: Nonessential personnel must maintain a minimal separation distance of _______.
K50 (Km19.84) BOD or HFD, whichever QD provides the greater separation distance.
What must be identified and afforded to all personnel prior to conducting EOD procedures?
Personnel protective measures
This includes measures intended to mitigate explosion effects.
What do intentional detonations require in terms of engineering controls?
Ammunition and explosives (AE) explosion effects engineering controls
Insufficient protective measures pose an unacceptable risk.
What should personnel be advised to do when positioned around typical inhabited buildings during emergency responses?
Remain away from exterior walls and windows and avoid PES direct viewing
What can be projected to distances greater than 10,000 feet during intentional detonations?
AE features such as noses, nose plugs, suspension lugs, strongbacks, and baseplates
These are also known as ‘rogue’ fragments.
What techniques should be employed to control fragment projections prior to detonation?
Engineering fragment control techniques including:
* Orienting AE away from personnel
* Surface barricading
* Open pit detonations
* Buried (tamped) detonations
What is the risk associated with improper engineering controls?
They may be incapable of effectively mitigating fragment and/or blast explosion effects
What can result from the intentional detonation of cased or uncased AE propellants?
A significant propellant-contributing mass detonating response
What factors can enhance explosion effects?
- Case material and thickness
- Method of initiation
- Point-of-initiation
- Charge geometry
What is the minimal separation distance for nonessential personnel in open areas during imminent AE intentional detonation?
Minimal K328 (Km130.16) BOD or MFD-H, whichever provides the greater separation distance
For essential personnel in the open, what is the minimal separation distance during imminent AE intentional detonation?
Minimal K328 (Km130.16) BOD or MFD-H, whichever provides the greater separation distance
What should be done when marking an area with a buried UXO?
Use surveyors tape or equivalent to identify the UXO location
The UXO should also be plotted on a map.
How much should minimal fragmentation distances be increased for the intentional detonation of stacked AE?
By 33 percent
Unless engineering fragment mitigation controls and personnel protective measures are employed.
What is the minimal separation distance for essential personnel in the open when dealing with non-fragmenting AE?
Minimal K328 (Km130.16) BOD
What does the term ‘fragmenting AE’ refer to?
Explosive material that is totally or partially encased in a non-pliable material
What is the risk associated with stacked AE and non-designed mode-of-initiation?
Increased risk of fragment size and velocity similar to non-design mode-of-initiation
What should be done if the condition of AE has degraded or may become exposed to unwanted stimuli?
Afford minimal K328 (Km130.16) BOD or MFD-H for both essential and nonessential personnel
True or False: Nonessential personnel can be positioned closer than essential personnel during an EOD operation.
False
What is the definition of ‘intentional ignition/burning’ in the context of AE?
Applicable to HD 1.3, 1.4, and 1.6 AE
What is the primary purpose of engineering controls in relation to explosion effects?
To mitigate explosion effects in the event of an accidental or intentional detonation.
What are personnel protective measures designed to do?
Provide protection to personnel against explosion effects.
What should be ensured regarding engineering controls intended to mitigate explosion effects?
They are designed properly for the intended purpose.
List some examples of engineering controls.
- Operation risk management protocols
- Management of AE operations using engineering principles
- Eliminating or reducing potential unwanted stimuli
- Employment of AE fragment engineering controls
- Application of EOD procedures
What does AE stand for?
Ammunition Explosive
What is an example of a personnel protective measure?
Use of designed pre-approved structures that effectively protect personnel from explosion effects.
Fill in the blank: The decision to perform a surface AE intentional burn or detonation should only be made after a _______.
[thorough AE explosion effects hazard and risk analysis is performed]
What should be analyzed in addition to minimal separation distances during intentional detonations?
Protective measures deemed to provide the most appropriate level of protection for the AE-specific threat.
What are rogue fragments?
Non-primary case fragmenting portions of AE that can be projected to great distances.
True or False: Engineering controls can reduce the chances of an AE item functioning as designed.
True
What is the recommended orientation for AE rogue fragment-producing portions during detonations?
Away from personnel and non-personnel exposures to be protected.
What is the effect of detonating stacked AE either simultaneously or sympathetically?
Similar effects on fragment size and velocity as non-design mode-of-initiation.
What should be increased by 33 percent for fragmenting AE detonated in stacks?
MFD-H (Minimum Separation Distance)
What are natural or artificial barriers used for in the context of explosion safety?
To provide protection equivalent to appropriate barricading.
What is the main function of barricades in surface detonations?
To protect against low-angle fragments and reduce shock overpressure loads.
What materials should large earthen barricades be made from?
- Cohesive fill material such as sand or clay
- Free from harmful matter, trash, debris, and stones
What is an ideal option for barricading during AE disposal operations?
An open pit and barricade combination.
What should be done if sufficient material isn’t available to construct a trapezoid-like configuration for a barricade?
Use earth-filled forms to maintain consistent thickness from bottom to top.
Fill in the blank: Barricades do not provide protection against _______.
[high-angle fragments or lobbed AE]
What is the minimum separation distance for intentional detonations according to K328 BOD and MFD-H?
Shall be adhered to
Unless otherwise specified and supported by test data.
What must be employed to ensure personnel safety during detonations?
Appropriate personnel protective measures must always be employed.
Where can a barricade be placed in relation to the PES and exposure?
Anywhere between the PES and an exposure.
What is the benefit of placing a barricade closer to the PES?
Provides slightly greater asset protection.
What happens when fragments travel greater distances?
Increases the risk for fragment ricochet, tumbling, and rolling.
What is required for the barricade thickness?
Must be thick enough to reduce fragment velocities and intercept ballistic trajectories.
What is the reference point for establishing barricade height?
The lower of the AE or the exposure if not of equal height.
What is the minimum height requirement for a barricade?
At least one foot above the line-of-sight for the entire length.
How wide should the top of the barricade be in relation to the AE and exposure?
At least 36 inches wider on both sides.
What must be done if multiple detonations are planned at the same PES?
The barricade must be inspected and repaired as required.
What is the expected reduction in overpressure loading when a barricade is utilized?
Reduced by approximately 50 percent under certain conditions.
What are the conditions for effective overpressure control by a barricade?
- Standoff within two barricade heights of the protected area
- Top of the barricade at least as high as the protected area
- Length of the barricade at least two times the length of the protected area.
What technique can be used as an alternative to barricaded surface intentional detonations?
Open pit disposal technique.
What is the nominal pit depth required for open pit disposal?
4 feet (1.22 meters), though this may vary.
What should be considered if vertical or near vertical high-angle fragments are of concern?
Refer to the Sandbag Fragment Mitigation Technique.
What is the limitation of the sandbag mitigation technique?
Limited to a single item detonation for select AE.
Where can the DDESB fragmentation database be accessed?
Available on the JEOD Portals.
What is the primary purpose of the water fragmentation mitigation technique?
To suppress fragments and reduce air blast effects from surface detonation of AE items
AE refers to ammunition and explosives. This technique is comparable to sandbag control methods.
What types of containers are used in the water fragmentation mitigation technique?
Small inflatable wading pool, plastic carboys, agricultural water tank
These containers are filled with water to provide protection against fragments.
Why is a single larger container preferred over multiple small containers in this technique?
A single larger container provides overall pit coverage and prevents gaps between containers
Gaps between cylindrical containers allow fragments to pass through with little resistance.
What is the benefit of the water control technique regarding AE fireball/thermal effects?
It provides a nearly immediate water-quenching effect
This helps to mitigate the thermal effects associated with explosions.
What is the maximum effective distance for tank debris throw when using this technique?
Greater than 330 feet (101 meters)
Proper design is essential for achieving this effectiveness.
In the vertical plane, what is the effective distance for plastic tank debris throw?
Greater than 100 feet (30.48 meters)
This indicates the effectiveness of the technique in vertical applications.
Does the water fragmentation mitigation technique account for secondary debris throw?
No, it does not consider other secondary debris throw for all scenarios
The focus is primarily on fragment suppression and air blast reduction.
Where can the DDESB fragmentation database be accessed?
On the JEOD Portals
This database lists select AE applicable to the water fragmentation mitigation technique.
Fill in the blank: The water fragmentation mitigation technique is applicable to a single item intentional detonation for the AE items listed in _______.
Table 29 (1 of 2) and Table 29 (2 of 2)
These tables contain specific items for which the technique is relevant.
What is the purpose of using larger deep bodies of water in explosion effect control?
To minimize above surface fragmentation, decrease launch velocities, and reduce fragment ejection angles.
Larger bodies of water can effectively absorb the shock and reduce the impact of explosions.
How do fragments produced by underwater detonations compare to those produced in air?
Underwater detonations produce larger spear-like fragments rather than typical chunk-like shapes.
These spear-like fragments have length-to-width ratios of approximately 1:4.
What happens to fragments from underwater detonations as they move through water?
They tumble as they move through the surrounding water medium.
This tumbling effect decreases above surface fragment velocity and increases the suppression of blast overpressure and noise.
What tool can aid in calculating above surface blast and fragment projection distances for underwater explosions?
The DDESB Buried Explosions Module (BEM).
This tool is available on the JEOD Portals.
What risk is associated with camouflets after initial formation?
They can remain filled with poisonous gases under high pressure, posing a risk to personnel if opened.
It is crucial to excavate or backfill camouflets to prevent collapse.
What is one method to reduce ground shock amplitudes?
Increase the separation distance between the PES and the ES.
This helps to mitigate the impact of ground shocks.
What is a recommended technique to reduce the number of AE items being disposed of at one time?
Reduce the amount of AE items being disposed of simultaneously.
Review relevant figures for PPV prediction and separation distance equations.
What are effective methods to reduce earth shock?
- Trenching
- Venting
- Buttressing
These methods can be labor-intensive and may require heavy construction equipment.
What is the purpose of trenching in the context of earth shock control?
To reduce the probability of earth-shock rupturing or breaking underground installations.
Trenching interrupts the shock wave from a buried UXO detonation.
What must be identified before conducting trenching operations?
Any critical or potentially dangerous utilities.
The trench should be dug close enough to the installation needing protection.
What is the recommended depth for a trench to protect underground installations?
At least 24 inches (610 millimeters) below the installation.
This ensures effective protection against earth shock.
How does venting reduce earth shock?
By permitting the explosion to vent upwards through a shaft, greatly reducing the shock.
Venting should be avoided in areas where blast effects pose a serious threat.
What does buttressing involve?
Placing sandbags or timber against walls and foundations to support them against explosion shock.
It helps to strengthen structures internally and externally.
What is the minimum width required for buttresses to protect against underground shock?
At least 10 feet (3.1 meters) wide at its base.
This ensures stability and effectiveness in shock absorption.
What can be used to protect against flying glass caused by overpressure effects?
Taping glass windows and skylights.
Other materials like tarpaulins, blankets, and bedding can also be utilized.
What is an effective method to prevent blast waves from coalescing?
Separation by Time, with a minimum 1-second delay between detonations.
The time interval can be calculated using the formula TI=7*W^1/3.
What must barrier design consider to prevent AE stacks from propagating blast waves?
Adequate standoff distances and the sensitivity of acceptor AE.
This ensures effective separation and control of blast effects.
