Sciencemadness Discussion Board

Explosion proof suit

medx - 2-5-2010 at 09:48

Hello
I think to take measures against accidents is very important for person who deals with energetic materials. So I want to provide explosion proof suit, like gloves, goggle, etc., against small explosions like explosion of blasting cap, etc. How can I provide?

Bowdlerize - 2-5-2010 at 22:52

See http://science.howstuffworks.com/blast-resistant-clothing2.h...

The cost of any armor that is light enough to be worn would be very high. I can't think of anything that could be done cheaply that would hold up to hypersonic frag (eg glass wear).

Welders gear (eg. gloves, apron & mask) would offer some protection but I imagine you would still loose fingers to 0.5>g HE if you where holding it.

unionised - 3-5-2010 at 09:04

I have a feeling that, if the bomb squad had explosion proof suits, they wouldn't have put so much effort into making robots.

An Orientation to Explosive Safety

The WiZard is In - 3-5-2010 at 16:10

Quote: Originally posted by medx  
Hello
I think to take measures against accidents is very important for person who deals with energetic materials. So I want to provide explosion proof suit, like gloves, goggle, etc., against small explosions like explosion of blasting cap, etc. How can I provide?



An Orientation to Explosive Safety
Betty W. Haft
Journal of Chemical Education 64 (6)541-44 June 1987

Explosives are chemical or physical systems capable of
extremely rapid exothermic reactions, which are generally
accompanied by high pressures at the reaction zone, gaseous
products, and a vast amount of heat and light. Such systems can
do a tremendous amount of work in a very short time. For this
reason, explosives are used for domestic, commercial, and military
purposes. Explosives also are used to clear forest areas, to open
canals, to build dams, to blast rock in construction projects, to drill
for oil, to mine ore, and for submarine activities.

Different kinds of explosives are used for different purposes.
Initiating explosives are used to set off more stable explosives. Low
explosives are used in some ammunition shells, blasting charges,
and fireworks. High explosives (HE's) are used as main charges,
especially in weapon systems.

Explosives are generally synthesized compounds or formulated
mixtures of compounds. However, some very dangerous explosive
systems can be accidentally created by both professionals and
laymen. Among these are methane-air mixtures found in landfills or
digester gas (sewage) plants located near residential areas,
undetected explosive devices left by the military in areas that have
since been converted to domestic use, the dust from the storage of
grain and fertilizers, and misplaced or lost blasting caps or
dynamites from construction projects. Appropriate precautions,
safeguards, and expertise must be used to eliminate the hazards
arising from these situations.

Classification of Explosives

Explosives can be classified in many ways (1). We have chosen
to limit our classification to the manner and the ease with which
they react.

Initiating or Primary Explosives

Primary explosives are generally sensitive to light, heat, shock,
sparks, and static electricity. They are very unstable and can be
detonated directly when acted upon by external forces. Examples
are mercury fulminate, Hg(ONC)2, lead azide, Pb(N3)2,
cyanurictriazide [C3N3(N3)3], lead styphnate, [C6H(N02)302Pb.
H20], and silver acetylide, [Ag2C2]These are usually packaged as
disc- or capsule-type detonators such as blasting caps used to
stimulate (set off) energetic reactions in other systems. Thus, lead
azide may be used to initiate a RDX- or PETN
(hexahydro-1,3,5,-trinitro-1,3,5triazine and pentaerythritol
tetranitrate, respectively) base charge. Special standardized
procedures and the proper safeguards must be enforced during the
preparation and use of initiating or primary explosives.

Low Explosives

Low explosives are chemical compositions or chemical
compounds that deflagrate by a self-sustaining reaction (burn
slowly, when unconfined) over a given period of time. When
confined, they may react with explosive violence. Therefore, they
are used often in propellants, where controlled burning is.
important, and in blasting operations. Black powder or gunpowder
is an example. Black powder is composed of charcoal, sulfur, and
potassium nitrate or sodium nitrate.

Black powder is sensitive to flames, sparks, friction. When
confined, black powder can be heated to a relatively high
temperature before an explosion will occur. However, it can be
ignited easily by a simple spark. Black-powder fires can cause
severe damage to other explosives and to individuals. Do not
attempt to fight a black-powder fire.

Black powder can be desensitized by pouring it into water. Even
empty black-powder containers should be washed before
discarding. Accidents have been reported that were caused by
contaminated black-powder containers.

High Explosives (Secondary Explosives)

High explosives (HE's) are chemical compounds or chemical
compositions that are much more stable than initiating explosives.
These are used almost exclusively for main charges. Some high
explosives are insensitive to mild shock, friction, flames, and heat,
and they are generally set off by blasting caps or other initiators.
When initiated by a blasting cap, the intense shock wave creates
many hot spots within the explosive causing extremely rapid
conversion of the solid into gaseous products with the subsequent
release of heat and light. The noise one hears from an explosion is
the shock wave generated by the hot, rapidly expanding gases
moving through the air at the speed of sound. Energy release is
almost instantaneous. High explosives are generally more easily
handled because of their added stability.

Some typical HE's are nitroglycerin [CH2(NO3)CH(NO3)
CH2NO3], trinitrotoluene (TNT), hexahydro-1,3,5-trinitro-
1,3,5-triazine (RDX), 1,3,5-triamino-2,4-trinitrobenzene (TATB),
pentaerythritol tetranitrate (PETN), dynamite (principal explosive
ingredient ammonium nitrate or nitroglycerin), and Composition B
(60/39/1 wtv/c, RDX/TNT/ wax).

Dynamite is the high explosive that the layman is most likely to
encounter. Its composition varies widely with its use. The principal
explosive ingredient is ammonium nitrate or nitroglycerin. However,
explosive or nonexplosive sensitizers often are added to bring
about its detonation. Sensitizers are materials that enhance the
detonation wave propagation characteristics, thus reducing the
critical (failure) diameter of the explosive. The critical diameter is
the minimum diameter of a cylindrical charge of high explosive
required to sustain a high-order, steady-state detonation. The
critical diameter is a function of charge confinement, charge densi-
ty, material particle size, and the initial temperature of the charge.
Sensitizers can also be impurities in the explosive. Liquid
sensitizers are usually added with carbonaceous absorbent
material to prevent leakage and to obtain a suitable oxygen
balance. Ethylene glycol dinitrate is an example of a successful
liquid sensitizer. Among the solid sensitizers are nitro-organic
compounds such as nitrotoluene, nitrostarch, and
nitronaphthalene. Aluminum and sulfur are also added as solid
sensitizers. Shock and heat can cause dynamite mixtures to
explode. Some grades of dynamite also give off poisonous gases.

Figure 1 gives the three basic steps in an explosive train. It also
shows the relationship between primary and secondary explosives.
Blasting caps themselves, common explosive devices, utilize this
relationship in their construction (2).

Detonating Devices

Two general types of devices or methods are used to set off
explosives: igniters and detonators. Igniters carry to the explosive
mass a flame that lights the explosive mass. Detonators deliver a
shockwave that causes the explosive to dissociate, detonate, or
burn rapidly.

Igniters are squibs (plain or electric), fuses, and delay igniters.
Squibs are small-diameter tubes of paper or straw filled with a
quick-burning powder; they have a relatively slow-burning match
head attached to one end. Although they are not safe, they are still
being used in some coal mining operations. Fuses are usually fine
particles of black powder wrapped in a coarse fiber forming a
ropelike material. Delay igniters are a combination of igniters and
fuses. They are standard and relatively safe for use in metal-min-
ing and tunneling operations. Most detonation devices, even
electric blasting caps, are unsafe in coal-mining operations
because of the probability of igniting the dust or gas present in the
mine.

Blasting caps are shells or cups made of copper or aluminum
alloy. They are closed at one end and contain two- or three-layered
charges of explosive within. The initiating (very sensitive) explosive
is near the open end of the cup while the less sensitive base
charge is closest to the closed end of the cup. The intermediate or
primary charge is in the center. Figures 2-5 show representations
of electrical and nonelectrical blasting caps (2). Electrical blasting
caps are set off by essentially instantaneous vaporization of bridge
wires, while nonelectrical blasting caps need a fuse for ignition.

Blasting caps are rather small and easily lost. Construction and
military personnel sometimes lose live blasting caps in areas
where they could be found and handled by children. They look like
shiny empty rifle or pistol shells. However, they are very dangerous
and could be injurious or even fatal to an individual if accidentally
exploded. Therefore, laymen are urged to be able to identify
blasting caps and notify the local police if one is found in a
residential environment. Do not attempt to destroy the blasting cap.

Domestic Explosive Systems

One very common domestic explosive system is the accumulation
of large volumes of gas-air mixtures. Such a system will ignite with
explosive violence. Sparks from a light switch or telephone, or from
static electricity, could cause such mixtures to detonate. Some
common sources found in buildings are natural gas (methane),
propane, or butane gas leaks, digester gas or landfill gas
accumulations in residential sections, and hydrogen-oxygen
mixtures near life-support equipment.

Fine dust particles from grain can evenly distribute themselves
among the available air in a grain elevator. This becomes a
suitable fuel for a reaction. A spark can ignite this fine
grain-dust-air mixture creating a violent explosion.

Ammonium nitrate fertilizer, when stored in garages or barns, can
sometimes become contaminated with oil from lawn mowers or
production machinery. The paper bag, ammonium nitrate, and oil
constitute an explosive mixture that could be ignited by a cigarette,
match, or even a backfire from equipment.

Fuels and flammable solvents, such as gasoline, lantern oils,
paint thinners, dry cleaning fluids, and adhesives, can be
vaporized even at room temperature. The vapors will travel an
unimaginable distance in a very short time forming an explosive
air-solvent mixture. These vapors can be ignited easily by
cigarettes, candles, sparks, or the pilot light of a gas stove or hot
water heater or any other source of flames.

When ignited, the system will explode with violence sometimes
destroying houses and killing or maiming individuals in the vicinity.
For example, when confined and mixed with the proper volume of
air, one pound of gasoline can explode with almost 10 times as
much energy liberated as would be liberated form one pound of
dynamite, see the example calculation in the Appendix. A gallon of
gasoline would liberate about 62 times as much energy as a pound
of dynamite. These chemicals should not be brought into the house
nor should they be used for anything other than their stated
purpose. Gasoline should not be used to clean soiled clothing,
floors, walls, etc. For flammable solvents intended for use indoors,
read labels carefully. All flammable solvents should be stored in a
well-ventilated area.

Aerosol cans are pressurized, and they contain a propellant that
is easily vaporized. When heated, the pressure within the can
becomes so great that the can explodes. Aerosol explosions are
not as energetic as those produced from flammable solvents or
fuels, but the flying pieces of metal can be lethal.

Dry chemicals used by laymen are also potential explosive
hazards. Calcium hypochlorite, a solid used to disinfect swimming
pools, is an example. The compound liberates chlorine gas when it
comes in contact with moisture. Chlorine gas is poisonous and can
cause rires and explosions if brought in contact with compounds
such as turpentine, ammonia gas, paint, kerorene, rubber, or
alcohols. As a general rule, add only a small amount of calcium
hypochlorite to a large volume of water, never the reverse. Use a
dry, clean scoop to transfer the chemical and store the original
container where it cannot come in contact with moisture.

The pressure inside a closed container can exceed the allowable
limits, causing the container to explode. A malfunctioning safety
valve on a hot water heater can create such an explosive system.
Exploding hot water heaters have been known to penetrate both
floors of a two-story building. Both thermostats and safety valves
should be checked periodically.

Sensitivity of Explosives

Explosives are considered thermodynamically unstable systems.
The ease with which they can be made to react by external forces
is a measure of their sensitivity toward that force. Heat, friction,
impact, flame, and light are a few of the external forces known to
initiate explosives.

Sensitivity to heat

One of the first sensitivity tests performed for safety purposes is to
burn milligram quantities of the explosive in/over an open flame.
Many explosives will melt before reaching an explosion
temperature. Others explode before they melt. The compound
mercury fulminate is an example of the latter. The burning process
is a self-sustaining reaction. The oxygen needed does not come
from the air but is found within the compound's structure.
Generally, explosive types are arranged according to their thermal
stability. Therefore, primary explosives < secondary sensitive HE <
secondary
insensitive HE (e.g., lead azide < RDX < TATB). More precise data
can be obtained using a differential thermal calorimeter. These
data are useful in planning for long-term storage of explosives.

Sensitivity to Impact

An idea of the stability of an explosive to mechanical impact can
be obtained simply by striking a few milligrams, resting on a metal
surface, with a hammer. Precise drop weight impact machines
have been designed to give more reliable data on impact sensitivity
or to establish the critical impact energy necessary to make the
compound or mixture explode. Table 1 gives results from tested
explosives.

Sensitivity to Friction

Equipment has been designed to measure the explosive
response to the stress and heat generated by friction when an
explosive is rubbed between rough surfaces. Soil or sandpaper is
sometimes used as an abrasive and a force or load is necessary in
this test. Table 2 gives results with some tested explosives (3).
TATB would not react under the conditions of the test; however,
RDX is sensitive to friction.

It is believed that friction causes heat to concentrate in localized
areas creating hot spots within the explosive. This results in a
self-propagating reaction that could lead to a detonation.

Explosive Reactions

Explosive reactions are exothermic, fast, and give off gaseous
products. They can be classified as (1) deflagrations, (2)
explosions, and (3) detonations. These can be controlled by
varying the composition and the manner in which the explosive is
confined. Brief descriptions of these three classes follow.

Deflagration

This is the autocombustion of explosive particles. Also, it is
usually a surface phenomenon. In the open air a deflagration is
generally slow (rate - meters/second) with practically no sound.
Gases, heat, and light are final products. The deflagration of black
powder is an example.

Explosions

Explosions are extremely rapid reactions characterized by a
sharp increase in pressure at the reaction site. Gaseous products
expand into a volume much greater than the original unreacted
material and can severely deform or totally destroy objects in the
vicinity. Explosions are accompanied by a loud sound. The
confinement of black powder in a blasting cap creates this kind of a
system.

Detonations

Detonations are explosions propagating at a constant rate that
exceeds the speed of sound (rate of a few kilometers/. second) in a
given substance. Detonations are almost always associated with a
shock wave traveling at a given velocity (detonation velocity) (4).
Although usually associated with high explosives, some less
sensitive explosives such as propellants and ammonium nitrate
can be made to detonate if properly confined.

The difference between an explosion and a detonation can be
shown best by describing their effects upon a physical object. If an
explosion is made to occur inside a 5-in. x 3-in. X 1-in. wooden
block, using a fuse and a metal sleeve filled with black powder, the
block is broken up into large chunks. Using a blasting cap and
following the same procedure the system can be made to detonate.
The wooden block is then blown into sawdust-size particles.
Although the energy in both systems is nearly the same, the effects
are quite different. In the detonation, the energy is delivered in a
much shorter period of time. This results in a much higher pres-
sure, which is very destructive.

Emergency Response

The time and manner in which one responds to a potentially
explosive situation or to an explosion can save both lives and
property. Most major facilities, such as factories, government
laboratories, and military establishments, have standard operating
procedures (SOP's), which outline in detail a sequence of
emergency responses. For the layman, two things are basic, (1) if
possible, leave the hazard area, and (2) notify the proper
authorities, the police, the fire department, or local military
ordnance group. In many areas, the emergency telephone number
is 911.

Conclusion

Gasoline (n-Octane)

For many, explosives are sources of otherwise unavailable
energy to do work. They are used by farmers instead of manpower
to remove trees, shatter boulders, and drill wells. To the
construction worker, they are a means of welding metal, of blasting
for road construction, or of digging canals. Comparison To
industry, explosives are big business in various aspects of
production, use, and transportation. The space industry, especially
in the use of solid-propellants rocket boosters, is a
good example. To the military, explosives are a means of
maintaining defense. Basic knowledge about explosive safety is of
a definite benefit to laymen who might accidentally create an
explosive atmosphere, or handle explosives occasionally.
However, no one should attempt to use explosives who has not
been trained to do so, To recognize a situation involving explosives
and to know how to deal with it can save many lives. This brief
introduction to explosives, their recognition, classification,
reactions, and safety aspects, can be used in conjunction with
other resource books such as the Dangerous Properties of
Industrial Materials (5), Explosives (6), and Terminal Ballistics (7).

Literature Cited
1. One example is found in Military Explosives; Departments of the
Army and Air Force Technical Manual. U.S. Government Printing
Office: Washington. DC, Nov. 1967; TM 9-1.300-214.
2. Brucker, E. W. Blasting Cap Recognition and Identification
Manual; International
Association of Chiefs of Police; USA, 1973; pp 2-7.
3. Johansson, C. H.; Persson, P. A. Detonics of High Explosives;
Academic: New York,
1979; p 137.
4. Fair, H. D.; Walker, R. F. Energetic Materials; Plenum: New
York, 1977; p 431.
5. Sax, N. 1. Dangerous Properties of Industrial Materials;
Reinhold: New York, 1979; pp
676-682.
6. Meyer, R. Explosives; Veriag Chemie: Deerfield, FL, 1981.
7. Backman, M. E. Terminal Ballistics; Naval Weapons Center.
China Lake, CA, 1976.

Appendix: Example Calculation

Experience alone is not always a safe index to sound practice

The WiZard is In - 3-5-2010 at 16:56

Quote: Originally posted by medx  
Hello
I think to take measures against accidents is very important for person who deals with energetic materials. So I want to provide explosion proof suit, like gloves, goggle, etc., against small explosions like explosion of blasting cap, etc. How can I provide?



Experience alone is not always a safe index to sound practice. In on accident
investigated by this Bureau, one man was killed and two women in an adjacent
building were injured by the detonation of a sulfur-potassium chlorate
composition in the process of being mixed, although it was stated that the mixing
operation involved had been in use in that plant for 20 years without mishap.
There is, of course, the possibility that the raw material used at the time of the
accident may have been different from that upon which past experience was
based. Thus, if the particular lot of sulfur employed were acid, abnormal
sensitivity of the chlorate-containing mixture might result. In any event, safe
experience, even for 20 years, would not justify a practice that exposed the mix
operator and others. Instead, the hazards should be recognized and isolation and
remote control provided.

Irving Kabik
Hazards from Chlorates and Perchlorates in Mixtures with Reducing Agents
U.S. Bureau of Mines
Information Circular 7340
December 1945.


franklyn - 3-5-2010 at 17:55

1. There is no such a thing as an " explosion proof suit ".
Resistent to high velocity fragments is a better description.

2. Garments cannot protect you from injury they can only reduce your injuries.

3. Garments are no substitute for good sense and
will not protect you if you have no sense.

4. If you feel the need for body armor you should first
think over what you are doing that is unsafe and first
mitigate your exposure and risk of injury.

5. It is much better to work behind a blast shield.
This is the same as a fume hood but made of
Bank teller style bullet resistent polymer glass.

6. http://www.botachtactical.com/rbrbalfacshi.html
If you need ballistic level protection it should be provided to you by
your employer. http://www.osha.gov/SLTC/personalprotectiveequipment

7. A pair of polycarbonate eyeglasses is indispensible and should
be worn at all times you work with chemicals anyway.
These are available at little cost from pharmacies as " reading
glasses " , if your eyesight is good get the one marked 1.00 or 1.25 .
Bigger is better , you are not making a fashion statement.

8. A visor is to be worn over your face and eyeglasses -
http://www.harborfreight.com/face-shield-with-flip-up-visor-...
A gas mask serves as well if you also work with toxic fumes.
http://www.sciencemadness.org/talk/viewthread.php?tid=2374#p...
http://www.sciencemadness.org/talk/viewthread.php?tid=2374&a...

9. Kevlar gloves and sleeves can defend from small fragments only.
http://www.discountsafetygear.com/kevlar-glove-wells-lamont....
http://www.discountsafetygear.com/stanco-kevlar-10in-knit-sl...
http://www.wellslamontindustry.com/Pdfs/Cut%20Resistant%20Se...

10. Used military Flak vests are available for $ 70 to $ 120
get one with a collar that provides neck protection.
http://www.olive-drab.com/od_soldiers_gear_body_armor_pasgt....
http://www.camotree.com/store/viewItem.asp?idProduct=243
http://shop.ebay.com/?_from=R40&_trksid=p3907.m570.l1313...

.

The_Davster - 3-5-2010 at 21:42

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi...

Rosco Bodine - 3-5-2010 at 23:02

At something like one half to three quarters of an ounce of high explosive undergoing a high order detonation without any containment in close proximity to a human being, the blast overpressure and shock alone is fatal .....even absent any shrapnel injury......therefore, any suit that would not be capable of somehow reducing or blocking the blast overpressure as an atmospheric effect would not provide effective protection from any significant amount of high explosive.

Explosives, Propellants and Pyrotechnic Safety...

The WiZard is In - 4-5-2010 at 06:28

Quote: Originally posted by medx  
Hello
I think to take measures against accidents is very important for person who deals with energetic materials. So I want to provide explosion proof suit, like gloves, goggle, etc., against small explosions like explosion of blasting cap, etc. How can I provide?



Noted in passing —

Free DL from DTIC.mil

itle: EXPLOSIVES, PROPELLANTS AND PYROTECHNIC SAFETY COVERING LABORATORY, PI...
Personal Author: MCGILL, RUSSELL
Corporate Author: NAVAL ORDNANCE LAB WHITE OAK MD
Source Code: 250650
Page Count: 128 page(s)
AD Number: AD0272424
Report Date: 20 OCT 1961
Distribution Code: 01 - APPROVED FOR PUBLIC RELEASE 23 - AVAILABILITY: DOCUMENT PARTIALLY ILLEGIBLE
Report Classification: U - Unclassified
Collection: Technical Reports

The WiZard is In - 4-5-2010 at 06:39

Quote: Originally posted by medx  
Hello
I think to take measures against accidents is very important for person who deals with energetic materials. So I want to provide explosion proof suit, like gloves, goggle, etc., against small explosions like explosion of blasting cap, etc. How can I provide?



Extracted from:

Journal of Hazardous Materials, 5 (1982) 359-371 Elsevier Scientific
Publishing Company, Amsterdam - Printed in The Netherlands

REMOTE HANDLING - BLENDING OF ENERGETIC MATERIALS
R. L. PARKS
Monsanto Research Corporation, Mound Facility,* Miamisburg, Ohio

In 1974 to meet a need for a less sensitive, but still energetic,
explosives initiator other than the commonly used primary explosives,
such as lead azide, Monsanto Research Corporation started the develop-
ment and production of a series of high energy pyrotechnics. It soon
became apparent that these high energy pyrotechnics were not simple
mixtures, easily handled, or subject to deflagration only. There was more
to it. The safety literature and technical data on pyrotechnics did not deal
fully with the materials under study. In-house work on small quantities,
less than a gram, indicated that these metal/oxidizer blends were truly
high energy mixtures.

Important production safety questions quickly surfaced. How large a
batch could be blended safely? Was there a "critical mass” for detonation?
How important was container shape and size? If these pyrotechnics
detonated, what would be their TNT equivalency On deflagration, what
would be the size of the “fireball”?

[0.5 kg (1.1) lb 10 feet] 260 ms duration.]

The objective of the test series was to determine the output energy of
the titanium powder and potassium perchlorate mixture in a mechanical
blender configuration representative of that used at Mound Facility. This
was accomplished by measuring: (1) the free field air blast output
equivalency as compared to an equal weight of TNT at the same scaled
distances;,(2) fireball diameter and duration; and (3) static pressure in a
closed chamber.

The composition tested consisted of one-third by weight of 2-micron
particle size dry titanium powder and two-thirds by weight laboratory
grade KCl04. The number of tests and the quantities of ingredients for
each test conducted are tabulated in Table 1. Five of the nine tests were
conducted in a simulated blender configuration to determine free air
equivalency, and the remaining four tests were conducted in closed
chambers to measure static pressure.


The Ti/KCl04 mixture exhibited characteristics of a detonation when
thermally ignited in a light, metal container. For the 500-g (1.10 lb) charge,
the TNT equivalent value was 53% at a scaled distance of 1.07 m/kg sup
1/3 (2.22 ft/lb sup 1/3) and approximately 75% equivalency at a scaled
distance of 3.24 m/kg sup 1/3 (8.16 ft/lb sup 1/3). Equivalent values for
the 250-g (0.55-1b) charge weight were 68% equivalency at the 1.07-m/kg
sup 1/3 . Because of the limited number of tests, it cannot be determined
whether the apparent difference at the smaller distance is significant. The
125-g (0.28-1b) quantity failed to detonate. This was probably due in part
to the volume of the container and the resultant depth of material.

A fragment analysis was made on the assumption that a detonation of the
pyrotechnic would occur in the hopper of the aluminum aliquot vessel. It
was also assumed that the detonation would equal 1 lb. of TNT, and that
all available material would detonate, the worst case. THE 0.5-in. THICK
STEEL WALLS WILL NOT STOP A PRIMARY FRAGMENT, 1/8 x 1 x 1
in. ALUMINUM, STRIKING IT AT RIGHT ANGLES.
[emphasis added]

---------
A suit made of Krell metal foil may work. When the craft
from Altair-4 with my foil arrives I'll put it to the test. [djh]

The_Davster - 4-5-2010 at 11:19

http://www.dtic.mil/cgi-bin/GetTRDoc?AD=AD272424&Locatio...


Most important thing is to keep quantities small. Proper gloves with <500mg prevented serious damage in the above paper. RDX or such things are not going to just randomly go off, usually only primaries allow such incidents to happen. Potential damage from a primary accident is easily mediated by using good initiators, so that only dozens of milligrams are needed, not poor primaries that require you to handle grams at a time.

The WiZard is In - 4-5-2010 at 11:32

Quote: Originally posted by The_Davster  
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi...



Glass Containers Shatter During Experiments with Volatile Materials.

Safety Shields/Forceps/Remote Handling Can Help Prevent Injuries

http://www.hss.energy.gov/publications/safety_health_note/ns...

The WiZard is In - 4-5-2010 at 13:59

Quote: Originally posted by Rosco Bodine  
At something like one half to three quarters of an ounce of high explosive undergoing a high order detonation without any containment in close proximity to a human being, the blast overpressure and shock alone is fatal .....even absent any shrapnel injury......therefore, any suit that would not be capable of somehow reducing or blocking the blast overpressure as an atmospheric effect would not provide effective protection from any significant amount of high explosive.



Deficiencies in the Testing and Classification of Dangerous
Materials. J.E. Settles. 1968. Annals New York Academy of
Sciences, Volume 152, Art.1. Pages 199-205.


"A total of 103 persons suffered injuries in the 81 accidents.
Seventy-eight fatalities resulted from these 81 accidents. "Of the
81 accidents included in this analysis, it was concluded that 23 of
them involved only fire, and the principal hazard was radiant
heat. It was further concluded that 44 of the accidents involved
both fire and explosion. From information available, it seemed
justified to assume that no more then 14 of the accidents were
characterized by supersonic shock waves that would fall within the
accepted definition of "detonating" reactions.

"The 14 accidents in which detonating forces were present resulted
in injuries to 35 persons and 34 fatalities. It appears from the
information available that only one of these 34 deaths resulted
from the blast overpressures that are associated with a detonating
reaction. However, this one fatality was not the result of blast
to human tissue. Rather, the blast pressure caused this individual
to be propelled as a projectile. The other 33 persons who died in
these 14 accidents were located at points where the density of
flying fragments, and in some cases, the lethal searing of radiant
heat were so great that their deaths were certain, even though
there had been no blast effects.

"A Serious And Disturbing Inconsistency Is Related To The Practice
Of Accepting A "Fire Hazard Only" Label On Reactions Of Such
Violence And Destructive Energy As Medium-Velocity Detonation,
Low-Velocity Detonations, High-Rate Explosions, Medium-Rate
Explosions, Low-Rate Explosions, And Even Reactions That Don't
Explode At All But Kill People By Burning Them To Death."


djh
--------
Takeo Shimizu
Fireworks: From a Physical Standpoint

The Principle of Caution.
One cannot anticipate all of the problems inherent in handling fireworks, despite all of
our knowledge and experience. Therefore we must proceed in an orderly fashion, e.g.:

(1)
(8)--Pay attention to things in the shadows.
(10)

Bowdlerize - 4-5-2010 at 14:56

I think Rosco was talking about HE, not fireworks.
Here is a link to a story on the 'White Butterfly' phenomenon, when overpressure destroys the lungs.
http://www.newsweek.com/id/100538

The WiZard is In - 4-5-2010 at 15:59

Quote: Originally posted by Bowdlerize  
I think Rosco was talking about HE, not fireworks.
Here is a link to a story on the 'White Butterfly' phenomenon, when overpressure destroys the lungs.
http://www.newsweek.com/id/100538



Granted. However, the only difference between high and low
explosives is — big pieces vs. little pieces.



9 Killed as Illegal Fireworks Shed Explodes in Ohio
New York Times 21v85

YOUNGSTOWN, Ohio, May 20 (UPI)

A shed full of what local authorities said were illegal fireworks exploded today killing
nine people and leaving two big craters.

The bodies were scattered across a wide area of Beaver Township outside of
Youngstown.

A search of the area determined that nine people were killed in the explosion, which left
one crater 10 feet across and up to 5 feet deep, and another 8 feet across and 3 feet
deep.

“They haven’t identified anybody yet” officially, Sheriff Nemaeth said. “Its Not A
Matter Of Being Burned, It’s A Matter Of Being In Very Small Pieces.”

---------
Fireworks bootlegging is under federal probe.
Chicago Tribune 24iv83

THE SHED behind Theodore Boruch’s bungalow in the west end of Hobart, Ind.
Disappeared in two rapid explosions.

One Severed His Legs At The Knees; The Other Catapulted His
Flaming Body 150 Feet Through A Stand Of Trees And Into A Field.

---------
Fireworks factory blast kills 11
‘Bodies lying everywhere’
New York Post, 28v83

BENTON, Tenn. (UPI) ---
An unlicensed fireworks factory exploded on a farm yesterday, killing at least 11 people
in a series of blasts that formed a mushroom cloud and hurled bodies into trees and
through the roof of a nearby house.

“We Have Counted 10 Torsos, But It Is A Pretty Gory Scene And
There Are Parts Of Bodies. There May Possible Be More Bodies,
There Was Not A Singe Body The Was Intact,” [County Sheriff
Frank] Payne said.

Bowdlerize - 5-5-2010 at 01:42

I found a paper by the army on the chance of overpressure damage to the lungs of a heavily-protected explosive ordnance disposal technician, supplied with a rigid enclosed thoraco-abdominal protector.

The TNT charges range in size from 1oz (28g) to 32oz (907g) at distances from 1ft to 3ft.

A mere 1oz at 1ft on the ground is into the lung damage range for a tech in a bomb suit kneeling down.

Blast Overpressure and survivability calculations for various sizes of explosive charges.

Contrabasso - 9-5-2010 at 11:02

On a SFX course I did the first demo was a det in a bean tin the baked bean tin became a colander, Again with water in there the bean tin was still badly pierced, bean tin filled with sand with a det inside and the can was belled out barrel shape but not pierced.

Now if you want to wear a two inch thickness of sand all over you are going to have to develop muscles! There would still be shock wave damage so, work carefully keep amounts small, and do all you can by remote control.

franklyn - 24-5-2010 at 01:06

Cursory protection need not be wildly expensive and can be had
with modest expenditure.

One can spend a lot of money on a visor which will not offer much
protection beyond that of a cheap visor. One can sandwich two or
more cheap visors which give significant protection short of an outright
ballistic face shield or mask , by standing them on a griddle to melt and
fuse their top edges together.

______________________________


Gloves are made of knit kevlar to be flexible but are not as puncture
resistant as the vest material which is also much stiffer. Wearing two
gloves say a large size over a medium size provides some minimal
defense. Tactile dexterity can be improved by painting the fingertips
with rubber cement.

Kevlar gloves 7 gauge heavy weight $ 5.49 medium
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=37034...
http://training.mcrsafety.com/pdf/SpecSheets/Gloves/9375M.pd...

Kevlar gloves 7 gauge heavy weight $ 5.49 large
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=38021...
http://training.mcrsafety.com/pdf/SpecSheets/Gloves/9375L.pd...

Again wearing two sleeves one over another improves defensive ability.

24 inch 2-Ply Kevlar Sleeves , 3 Pair - $ 14.99 extra wide
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=12045...

All in one has the drawback that a glove cannot be removed to free
a hand when needed without removing the entire piece.
Kevlar glove & 24 " sleeve $ 12.67 Pair
http://www.magidglove.com/Magid-CutMaster-93KV24SL-100-Kevla...

________________________________


German Kevlar Flak Vest
Detailed description
http://www.worthpoint.com/worthopedia/body-armor-ballistic-f...
Pictures attached below
Flak Vest - $ 50 - 70
http://www.keepshooting.com/selfdefense/bulletproof-vest/ger...
http://www.gunnyssurplus.com/german-flectar-flak-vest.html
http://www.hessenantique.com/ProductDetails.asp?ProductCode=...
http://www.mainemilitary.com/productcart/pc/viewPrd.asp?idca...
http://www.centerfiresystems.com/germanflectarcamovest-usedp...

.

Attachment: Flak Vest.zip (753kB)
This file has been downloaded 652 times

unionised - 24-5-2010 at 12:18

I wonder if this thread might be summarised as
1 Buy the best gear you can afford.
2 Assume it won't work.

franklyn - 24-5-2010 at 13:56

For working with primary explosives and fabrication of initiators in the few grams required ,
being protected is realistic. Most important is avoiding direct handling using plastic tools
instead to manipulate materials. Needless to say , with a contact explosion trauma will be
extensive. Gloves will only contain thumb fragments from perforating you , and your fingers
from flying off into the walls. It's not recommendable to work alone , have a good speed
dialer handy which you can activate with a pencil clenched in your teeth. All reasons why
I'm not a big fan of primaries in general , favoring electric wire detonation. What results
can be expected all depends on the nature of the explosion. With a sizable amount that
causes dismemberment , enough protection is provided that you will not be killed outright
but you will have to adapt to prosthetic replacements of your maimed arms. Anything
larger than this , spare yourself the illusion of safety and work comfortably in normal
clothing since you will never know what hit you.

P.S.
Remote robotic manipulation is a viable future prospect
but is not as yet reliable and readily available.

.

Jelly bag

The WiZard is In - 24-5-2010 at 15:37

Seriously energetic material are mixed using a
Jell-bag.

Run it through Google.com/books


franklyn - 25-5-2010 at 22:04

Quote: Originally posted by The WiZard is In  
Seriously energetic material are mixed using a Jell-bag.
A blast shield by any other name

Treatise on general and industrial organic chemistry Vol 1
Page 309 _ Detonators , http://tinyurl.com/389f7cz

.

franklyn - 27-5-2010 at 07:13

Here are the links to the citation as posted by The WiZard is In , above _
http://www.sciencemadness.org/talk/viewthread.php?tid=13791#...

Explosives Prpellants & Pyrothecnic Safety
http://handle.dtic.mil/100.2/AD272424
redirects to _
http://www.dtic.mil/cgi-bin/GetTRDoc?AD=AD272424&Locatio...

.

quicksilver - 27-5-2010 at 08:46

Not only do I totally agree with franklyn on this but the illusion of "proof" is just that. Anyone who has either worked with or is a technician knows that it's DISTANCE from the explosion that makes any difference at all. In reality, primaries are squared upon themselves in terms of their brisancy properties. So that if you are dealing with 100mg of lead azide & a contact detonation occurs upon the hand, the likelihood is a great deal of tissue disruption. Twice that and their is a likelihood of dismemberment of a digit. I use the term "likelihood" because there are quite a few influencing factors. However once that detonation is moved (approx) one foot away from the human hand, the damage will become substantially less. {This one example of why detonators are handled by the leg wires or fuse.}

There IS NO way to quantify what will happen with this or that weight of this or that explosive because just SOME of the influencing factors include distance, angle (of propelled force), solidity of the limb (can IT move, or is it trapped in place), type of and temperature of explosion (BP or Flash can remove a limb just as aluminum/silver azide can), containment or lack thereof the explos, & the dynamic type of the material (is it powdered; compacted, crystalline, or plasticized). There are SO many factors that go into what occurs that the research into the use of modern explosive weapons is enormous & often even then, insufficient.

During various wars, the use of a simple electrical detonator in a booby-trapped telephone receiver resulted in death. The escape FROM death by an individual close to a hand-grenade is well documented. There are just too many variables. That's why anyone with an ounce of sense notices his heartbeat and respiration rise at times of proximity to an (potential) explosion.



***EDIT:
If you really want to learn more about safety don't look at what is published by the ISEE but rather that which is available in the handling of pyrotechnics. Because pyrotechnics are those that occur is a direct contact scenario in terms of raw materials and direct packaging (not automated).
Those safety issues that occur in order of causality are static & friction. Both of which are often unseen & very common.



[Edited on 27-5-2010 by quicksilver]

Your Government Protecting You From ' Madmen '

franklyn - 21-8-2014 at 10:22

https://beta.congress.gov/bill/113th-congress/house-bill/534...
H.R. 5344 is a bill currently going through Congress that would ban the civilian purchase of body armor. Violation would carry CRIMINAL penalties, including up to ten years in prison. Whatever your stance on firearms, we can agree that one cannot hurt someone with body armor. People buy body armor for protection. Your government claims that “ criminals and rampaging madmen ” can “ wreck havoc ” while wearing body armor, and it’s important to shield POLICE from these nefarious individuals.

.

roXefeller - 21-8-2014 at 13:12

Quote: Originally posted by franklyn  
https://beta.congress.gov/bill/113th-congress/house-bill/534...
H.R. 5344 is a bill currently going through Congress that would ban the civilian purchase of body armor. Violation would carry CRIMINAL penalties, including up to ten years in prison. Whatever your stance on firearms, we can agree that one cannot hurt someone with body armor. People buy body armor for protection. Your government claims that “ criminals and rampaging madmen ” can “ wreck havoc ” while wearing body armor, and it’s important to shield POLICE from these nefarious individuals.

.


That's dumb, why don't they just ban the guns used by the madmen, oh wait, gun control act of '34, '68, '86, '94, '05. Funny how all those bills don't seem to make a dent in the violent crimes. By the way, the short title and official title of the bill:
Quote:

Short Titles as Introduced:
Responsible Body Armor Possession Act

Official Title as Introduced:
To prohibit the purchase, ownership, or possession of enhanced body armor by civilians, with exceptions.



It doesn't seem like 'responsible possession', but just outright ban for any non-agent. The short title makes me guess they're trying to fool people into voting-ay-without-reading. What are they going to tell the mothers who are buying ballistic backpacks for their children? Surely those can't be sold, because madmen will stitch them into a vest.

Bert - 21-8-2014 at 22:34

Ain't chemistry. Ain't energetic materials. Ain't "explosion proof suit". Is USA politics. I hate the madness du jour too. But: Put it in legal & social IF chemistry related , or whimsy otherwise.

You've both been here long enough to know how we roll. Thanks!

macckone - 2-9-2014 at 09:31

Quote: Originally posted by franklyn  
https://beta.congress.gov/bill/113th-congress/house-bill/534...
H.R. 5344 is a bill currently going through Congress that would ban the civilian purchase of body armor. Violation would carry CRIMINAL penalties, including up to ten years in prison. Whatever your stance on firearms, we can agree that one cannot hurt someone with body armor. People buy body armor for protection. Your government claims that “ criminals and rampaging madmen ” can “ wreck havoc ” while wearing body armor, and it’s important to shield POLICE from these nefarious individuals.

.

I don't agree with this bill but it only applies to type III body armor.
Curiously it doesn't prohibit type I, II or IV body armor.
It is already illegal for violent felons to posess body armor in the US.
You would think that if they were concerned about body armor
they would include type IV. Type I and II will generally protect
against hand guns (low power and high power respectively).
Type III is for rifle rounds. Type IV is much heavier and not something you want to wear around. It is designed to resist AP rifle rounds.
Type IV is what you would want to resist explosion fragmentation.
Actual explosion resistant body armor is much less flexible than type IV.
Explosion resistant body armor is not really for working with explosives.
As a previous poster indicated distance is the best protection.

Fantasma4500 - 3-9-2014 at 09:20

juggernaut suit

but i think what you may have to take caution against in a lab is small fragments, unless if you are somehow deciding to put a decent charge into a thick metal tube and then lob it on a stove and stare at it

usually what happens in a lab is smaller gas explosions, this wont give that violent glass fragments, rather large pieces at relatively low speed
then theres the few things where powerful explosives blows a hole in a flask etc, this produces very fine glass shrapnel, thin metal sheet will cover against this, aswell as low velocity glass PIECES, rather than glass dust

soo...
get some SS sheet and a welders apron
perhaps aluminium will do if you get a nice hard alloy? then cut some plates and put them on the inside of the apron and call it a day
supposing you can keep it in place using steel wire or similar
you want plates to overlap each other like 'dragon skin' bulletproof armor, so you can still move about

i think that if you consider the gas pressure then it will most likely destroy you no matter what you try, but you gotta be on a decent scale before that becomes a factor to count in, as said.. try to distill a pipebomb and you will get hurt by some means

http://puu.sh/bjRaS.jpg

keep it simple