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PtC~r~NYARSENACSC04tIC AND TECHNICAL INPO"'MATtON W)NCe
CX. A
I.D ILUJ
SEP 22 19E5
T1119 DOCUMENT HAS BEEN API"10)17lD Pon PUBLICRELEASE AND SALE; ITS D1SS'fF%13LTlIS~1 UNLIMITED
Final T'echnical tepwt J- A
TNT EQUIVALENCY OF BLACK POWDERVolume I:L -Management Summnary and
Technical Discussion,
Sepf- 72
I"! LTRI ! H-J6265-3 -V!.
Prepared by:
/' H yla S./'Napadensky\7\James J Swatosh, ..
, -J4
D DCIIT Research Institute
Chicago, Illinois 60616 'S P 2 19 7
Under the technical direction of STU'~Manufacturing Technology Directorate BPicatinny Arsenal
TI S DOCI-11i-:,T 1 III\,Y~t ror, 11jTr,,1f~ ~ ~ ~~ ~~B ILEASL A i,') S AM>.....~-ii 15uNA:ir
Lii' -- ! --
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FOREWORD
IIT Research Institute has conducted an experimental study
to determine the TNT equivalency of Black Powder. The work was
conducted for Indiana Army Ammunition Plant under a modification
to Purchase Order 01-46628. Work was carried out during the period
January I to June 1, 1972. This work was conducted as part of the
engineering support required for establishing a new Black Powder
manufacturing facility at the Indiana Army Ammunition Plant. Tech-
nical guidance was provided by Mr. R. Rindner and Mr. L. Silberman
of Picatinny Arsenal. This document entitled "TNT Equivalency of
Black Powder" is the final report on this effort. In addition to
the authors, personnel who have mnade material contributions to the
program are R. Babler, D. Morita, A. Humphreys, R. Joyce, D. rrdina,
J. Daley and D. Baker.
The results of this effort are presented in two volumes:
Volume I, Management Summary and Technical Discussion, presents a
brief, concise review of the study content, summarizes the princi-
pal conclusions and recommendations, and provides a discussion of
the test data and the data analysis. Volume II, Appendices, con-
tains summaries of the raw data, computational method, computed
equivalencies, and detailed description of the instrumentation
system.
Respectfully submitted,lIT RESEARCH INSTITUTE
H~a{S. Napagensky
Senior Research Engineer
APPROVED:
~~~... . .[
D. C. AndersonManager '""
Shock Dynamics and Safety Analysis
Engineering Mechanics Division .,, . .....
. i.. ~Ot
I-CIAL
..
'! PABS TRACT
The purpose of this investigation was to experimentally de-
n termine the maximum output from Black Powder explosive reactionsin terms of airblast overpressure and impulse. The measured pres-
g sure and impulse values are compared with those produced by a
Ihemispherical surface burst of TNT in order to determine the TNT
equivalency of Black Powder.
Black Powder charges ranging in weight from 8 lbs to 150 lbswere evaluated under different levels of confinement. The TNT
[ Iequivalencies for the final product were found to range betweenzero to 43 percent for impulse and zero to 24 percent for pressure,
depending upon the level of confinement, the weight of explosive
and booster, and the distance from the explosion. A limited num-
Iber of tests were carried out on 27 lb charges of the jet milledproduct, an in-process form of Black Powder. Its TNT equivalency
ranged from zero to 22 percent for impulse and zero to 11 percentfor pressure. It is recommended that a maximum impulse equivalency
value of 24 percent be used for the process building and glaze
I house design since tests carried out under conditions existing in
these buildings indicate that these values are applicable. How-
-i Iever the value of 4L3 percent impulse equivalency should be applied
to the rack house and loading dock. The application of this TNTequivalency data to the design of the improved Black Powder process
manufacturing plant, would result in the reduction in the cost ofconstruction of tne new facility.
IJ
I: iii
L, OBJECTIVE
2. SUM tAiKY 1
3. CONCLUSIONS, RECOMMENFATIONS iND APPLICATTONS 2
i 4. INTRODUCTION 5
5. TEFT CONrIGURaTIONS 7
5.1 Confined/Unconfined Test Series 75.2 Booster Size and Shape Effects 10
6. TNT EQUIVALENCY TEST RESULTS 15
6.1. Overview of TNT Equivalency Test Results 21
7. EFFECT OF VARIOUS PARAMETERS ON TNT EQUIVALENCY 29
7.1 The Effect of Heavy Confinement 297.2 The Effect of a Steel Base Plate 377.3 The Effect of Small Standoff Distance 417.4 The Effect of Black Powder Weight a1,7.5 The Effect of -noster Weight 497.6 The Effect of Booster Geometry 557.7 The Effect of Type of Explosive Used
for Boosters 577.8 Comparison of the TNT Equivalency
of the Jet Mill Product and Black Powder 647.9 The Shape of the Pressure Equivalency Curves
and the Effect of Errors in Measurements 69
8. RESULTS OF TESTS ON SAND AS AN INERT SIMULANT so
APPENDICES (Bound Separately)
APPENDIX A: Measured Pressure-Impulse Data
APPENDIX B: TNT Equivalency Calculation Procedure
APPENDIX C: Computed Values of Pressure and ImpulseEquivalencies, Based on Curve Fitto P-', and I-?, Data Points
APPENDIX D: Instrumentation
APPENDIX E: Raw Data Point Equivalencies
iv
F !I
ILLUSTVO1 tONS
1 T a e t A .,: ' a."
2. no .... ic fined Test Setip 9
3. gooster Size and Shape Test Setup if4. Press-ure a3d Scaled Impulse for Various Booster
Weight,",, 25 lb Black Powder 19
1 5. Effect of Booster Weight on TNT Pressure Equivalency,Confined and Unconfined 25-27 lb Black Powder 19
6. TNT Pressure Equivalency of 25 lb Black Powder,! as a Function of Booster Weight, for Sele:cted
Scaled Distances, 20
7. Envelope of Pressure and Impulse Equivalency as aFunction of Booster Weight for 4ll Tests, ScaledDistance x=2 22
8. Envelope of Pressure and Impulse Equivalencyas a Function of Booster Weight for All Tests,Scaled Distance =5 23
9. Envelope of Pressure and Impulse Equivalencyas a Function of Booster Weight for All Tests,Scaled Distance ',,-10 24
1 10. Pressure and Impulse Equivalency as a Function
of Weight Ratio, for All Tests, Scaled Distance ,-2 26
11. Pressure and Impulse E'juivalency as a FunctionI of Weight Ratio, for All Tests, Scaled Distance =5 27
12. Pressure and Impulse Equivalency as a Functionof Weight Ratio, for All Tests, Scaled Distance :=10 28
13. Effect of Confinement and Booster Weight on TNTPressure Equivalency, 25-27 lb Black Powder 311 14. Effect of Confinement and Booster Weight on TNTImpulse Equivalency, 25-27 lb Black Powder 32
15. The Effect of Booster Weight and Confinement on TNTPressure Equivalency, 140 and 150 lb Black Powder 33
16. The Effect of Booster Weight and Confinement on TNTImpulse Equivalency, 140 and 150 lb Black Powder 34
17. Effect of Booster Weight and Confinement on TNTPressure Equivalency, 64-75 lb Black Powder 35
18. Effect of Booster Weight and Confinement on TNTImpulse Equivalency, 64-75 lb Black Powder 36
19. Comparison between Steel Base Plate and GroundSurface on the TNT Equivalency of Black Powder 38
20. TNT Pressure Equivalency of 75 lb Black Powderas a Function of Booster Weight, for SelectedScaled Distances 39
V
J
i
iLLUSTRA1 IONS (Contd)
Pacr21, TNT Impulse Equivalency of 75 lb Black Powderas a Function of Booster Weight, for Selected
Scaled Distances, 4022. Effect of Charge Wt on TNT Pressure Equivalency;
3 Confined Tests, Squib or .024 lb Booster Initiation 4223. Effect of Charge Wt on TNT Impulse Equivalency;
Confined Tests, Squib or .024 lb Booster Initiation 4324. The Effect of Black Powder Weight on TNT Pressure
Equivalency for All Tests Using 0.5 lb Boc'ters 4525. The Effect of Black Powder Weight on TNT ImpulseJ Equivalency for All Tests Using 0.5 lb Boosters 4626. The Effect of Black Powder Weight on TNT Equivalency
for All Tests Using 1.0 lb Boosters 4727. The Effect of Black Powder Weight on TNT Equivalency
for All Tests 'sing 1.5 lb Booster 4828. TNT Pressure Equivalency of 25 lb Black PowderIas a Function of Booster Weight, for Selected
Scaled Distances, "1 5029. Impulse Equivalency of 25 and 27 lb Black Powder
as a Function of Booster Weight, for SelectedScaled Distances, -, 51
I 30. TNT Pressure Equivalency of 75 lb Black Powderas a Function of Booster Weight, for SelectedScaled Distances 52
31. TNT Impulse Equivalency of 75 lb Black Powderas a Function of Booster Weight, for SelectedScaled Distances, A 53I32. TNT Equivalency of 140 and 150 lb Black Powder
as a Function of Booster Weight, for SelectedScaled Distances, N 54
33. The Effect of Booster Geometry on TNT Equivalencyof Black Powder 56
34. Pressure and Impulse Equivalency as a FunctionIof Weight Ratio, for All Tests, Scaled Distance =2 58
35. Pressure and Impulse Equivalency as a Functionof Weight Ratio, for All Tests Scaled Distance N=5 59
36. Pressure and Impulse Equivalency as a Functionof Weight Ratio, for All Tests, Scaled Distance A=0 60
3 37. TNT Pressure Equivalency of 25 lb Black Powderas a Function of Booster Weight, for SelectedScaled Distances, N 61
vi
i ILLUSTRATIONS (Concl:)
1 33. Impulse Equivalency of 25 and 27 lb Flack Powderas a Function of Booster Weight, for SelectedScaled Distances 62
g 39. Comparison between the Behavior of Black Powder avLdthe Jet Milled Material and the Effect of Confinementon Pressure Equivalency for 8 and 27 lb Charges,
.024 1b Booster
40. Comparison between the Behavior of Black Powdey andthe Jet Milled Material and the Effect of Confinement
! I on Impulse-Equivalency for 8 and 27 lb Chargei," 0.024 lb Booster (-6
41. Effect of Charge Wt on TNT Pressure Equivalency;Confined Tests, Squib or .024 lb Booster Initiation ('7
42. Effect of Charge Wt on TNT Impulse Equivalency;Confined Tests, Squib or .024 lb Booster Initiation 68
TABLES
1. In-Process Material Quantity -nd TNT Equivalency 4
2. Range of Test Parameters Evaluated 6
3. Confined/Unconfined Tests, Initial Series 11.4. Unconfined 'rests, Booster Effects Series 145. Black Powder and Jet Milled Material, Range of Test
Parameters Evaluated and Their Shot Numbers 16
6. Calibration Tests using Sand as an Inert Simulant,
Range of Parameters Evaluated and Their Shot Numbers 17
Vii
pA
I1. OBJECTIVE
The purpose of this investigation was to experimentally de-
termine the maximum output from Black Powder explosive reactioirs
in terms of airblast: overpressure and impulse. The measured pres-
sure and impulse values are compared with that produced by TNT inorder to determine the TNT equivalency of Black Powder, which is
defined as the ratio of the weight of TNT to the weight of '11ack
I Powder that would produce the same overpressure (or impuise) at
t-ie same distance.
12. SUMMARY
in order to meet the objectives of this program a total of1 72 tests were carried out. This number consisted of 42 tests on
CIL* Black Powder; six tests on thie jet milled material , an in-Iprocess form of Black Powder; 19 tests on an inert simulant, sand,,
to isolate c'ie booster output effect; and five calibration tests,using a C-4 booster, to check on the accuracy of the pressur.2 gagesond recording system. The major parameters evaluated for their
effect on TNT equivalency were the weight of the Black Powder, the
I amount of confinement and the weignt of the explosive booster used
to initiate the Black Powder. A limited number of tests were car-red out to evaluate secondary effects; these were booster geometry
and type of booster explosive.
fThese effects were measured in terms of airblast overpressureand impulse at six gage station locations. These stations were
spaced at selected scaled distances ranging from approximately 2 to15 ft/lb / . The TNT equivalency was found to depend upon chargeI , weight, scaled distance and amount of confinement. Equivalencies
for Black Powder ranged from zero to 43 percent for impulse andzero to 24 percent for pressure. The equivalencies for the jet
milled material ranged from zero to 22 percent for impulse and 7eroto 11 percent for pressure. The condition for which the maximum9 value of 43 percent was found applies to the pack house and loadingdock. For actual production in the process building and glaze
CIL - Canadian Industries Limited
!I
II
house a maximum value of 24 percent for impulse equivalency should
I be used because of the small quantities and/or a lack of confine-
menit.
me * Confinement effects are significant, small increasesin the degree of confinement substantially increase
i the TNT equivalency.* Pressure and impulse equivalency increases with in-crease in both Black Powder chare weight and boosterweight. The maximum values obtained were 24 percentfor pressure equivalen.-v at a scaled distance of 7 and43 percent for impulse eqLivalency at a scaled dis-tance of 2.
e When all data are compared on the basis of equal ratioof booster weight to Black Powder weight, the TNT equiv-alencies for 75 and 150 lb cnarges are essentially equalwhereas 25 lb charges have lower equivalency values.
* Pressure equivalency increases with scaled distance,I 1 reaching a maximum vie at a scaled distance of be-tween 7 and 10 ft/lb and then decreases.
• Impulse equivalency does not vary appreciably withscaled distance, but it is always greater thpn the pres-sure equivalency.
3. CONCLUSIONS, RECOMMENDATIONS, AND APPLICATIONSi IThe TNT equivalency of Black Powder was found to range between
zero and 43 percent for impulse and zero to 24 percent for pressure.I The limited number of tests on tile jet milled material showed that
its impulse equivalency ranged between zero and 22 percent and
zero percent pressure. The TNT equivalency dependedprimarily upon the degree of confinement, the quantity ofexplosive, booster material and the distance from the explosion. Itshould be noted that tne conditions for which the maximum values of
43 percent equivalency were obtained are never realized in the pro-cess building or glaze house, that is heavy confinement, large con-centrated weights, and large initiation sources. Although substan-
tial quantities of Black Powder exist in the glaze house (4500 lbs)the Black Powder is in a wood barrel, which does not constitute
Ic on finement.
The quantities of Black Powder evaluated in this investigation
were large enough to constitute a full-scale evaluation of the
2
!I
Iquantities to be processed in the process building of the improved
b Black Powder manufacturing facility. It i3 recommended that thetest results reported herein be incorporated into the final facil-
ity design. It is believed that the cost of the new manufacturing
facility could be reduced if buildin construction and Quantity-
distance siting were based on the data acquired on this program.
IOn the basis of the concept studies for the improved BlackPowder manufacturing facility, the approximate accumulazion of
I material in tiie process building is shown in Table 1. The maximumvalue of impulse equivalency associated with the given weights and
I confinement levels are also provided in this table. Thus it is
seen that tae data reported herein has direct application and canfprovide significant guidance to tne optimization of the new facil-
ity desigr'.fThe following recommendations are not critical to the designof the new facility, however additional savings in cost of construc-tion may be possible after more TNT equivalency data are acquired.
i These tests should be carried out for selected conditions, so as tofill in the voids in the data. These evaluations should include:
I S Test on Black Powder charges weighing more than 150 lbsto determine if maximum equivalencies have been achieved,and/or to determine if the critical mass for maximum out-
i put has been fotLnd. These data would have particularapplicatior to the load dock, pack house and to the glazehouse where approximately 4500 lbs will be polishe.dried, and glazed at one time. This evaluation wouldnot be necessary if a continuous glazing and drying pro.cess is developed. At least one full-scale 4500 lbtest should be carried out.I An eval.uation should be made to determine the TNT equiv-alencies of the in-process forms of Black Powder. Thisincludes the jet mill product, press cakes, prebreakerchips and green grains. It is believed that even lowervalues of TNT equivmlency would be found for all in-process forms of Black Powder. To increase the validityof this work, tests should be carried out under the sameconditions of confinement, geometry, and weights asexist in the process.
I3!L
C;4 i4 0.4 C4) N
cc cc (A 4) 410 N -
4). -m1 0 4 o ,C4 4 w 4 8442 )r-4
" 4 )4. F4 0) -v4 N4w4t0w.1 LM Oo~u W (00P-4CI (1 -r COJG .w4 U.
H - 0 0 C J -L -- 4 C :J w o-- v -v J-4 W1 0 0 0U.4JJ1 -44
60r "4 0 4) 41 0) 41 4j-r4 cn 0 4-W *'**4"- ) 4 , 1 o -. m r - 4 c :2 (
-,4 J0 0 -r W W~~.44a
~44 WAca UQ U CJ *,40 00 W 4.1 n .
U-441W 0.1 .2v- 0 i .v4 0toj~ o 1 o no-
44 4 -A0 o-,W4 U) P- a)r aa -r- W C (0 r .4 a) : r4 U M C)c
1) 14. 4.J 4 W) 9 ()4M 00 W rO.e 0 "04 0 u 0
C12 ca 44a"4 W~~. U) W )-f JJ U) *
1.4o V w4 .4)41
14 "4 Qe -.A 0
0v44 0 r44
I
j As secondary recommendations:
0 The distances at which pressure measurements are madeshould be extended to scaled distances ,ss than 2and to intraline distances of 20 ft/lb i for allcharge weights.
a To fill in voids in the data, larger size boostersshould be used to confirm that maximum output has infact been determined.
4. INTRODUCTION
A series of 72 tests were carried out to determine the TNT
equivalency of CIL Black Powder and jet milled material, an in-
process form of Black Powder produced by the improved Black Powder
process. Tne experimental work was carried out at the lIT Research
Institute's explosive research laboratory, located near LaPorte,
Indiana, for TAAP, under the tecnnical supervision of PicatinnyArsenal.
The 72 tests consisted of 42 tests on CIL Black Powder; six
tests on tne jet milled materinl; 19 tests on sand, as an inert
simulant, to i3olate the booster output effect; and five calibra-
tion tests, usiug a C-4 explosive booster, to check on the accuracy
of the pressure gages and recording system.
The parameters that were evaluated for their effect on TNT
equivalency, with respect to blast overpressure and impulse, were
the weight of toe Black Powder, the type of confinement and the
explosive booster weight. A limited number of tests were carried
out to evaluate secondary effects: booster geometry and type ofbooster explosive. Table 2 shows the range of major parameters
evaluated. Each entry in the table represents more than one test,
as tests at each condition were repeated two or three times.
IAII5 ..1
|I.
ITABLE 2
RANGE OF TEST PARAMETERS EVALUATED
Jet millBooster Black Powder Weight Pdt MiglProduct Weight
Explosive (ibs) (ibs)
1 Weight(Ibs) Type 8 25* 75* 150 27
-- Squib C
0.024 Tetryl C U C U C U C C U
1 0,25 C-4 U
0.50 C-4 U U
0.54 9404 PBX U
I 1.00 C-4 U U
1.50 C-4 U U
3.00 C-4 U
I Initial series of 15 tests were for 27 and 64 lbs. The remr-der were at the specified values.
- +The letter U stands for unconfined test configurations and C
t ' I for confined tests. ,
I :
I.
I!I'J
6
Li
S I
1 5. TEST CONFIGURATIONS
A schematic diagram of the physical arrangement of the
3 test area is shown as Figure 1. It consists of a concrete slab75 ft long by 10 ft wide. Pressure transducers were installed
I flush with the top surface of the concrete slab in mechanically
isolated steel plates. The steel plates cover a channel in which
gage leads are placed. The test item is placed adjacent to one
end of the concrete slab. Before each test this sandy area is
leveled even with the concrete slab.
! |For these tests six gages were mounted on the blast pads.
*[ Overpressure was measured and total positive impulse was elec-
I tronically computed. See Appendix D for a complete description
of the overpressure and impulse measurement systems.
I Fastax motion pictures were taken of all the experiments.Fiducial markers were located behind the charge with respect to
I the camera,in the camera's field of viewas shown in Figure 1.
1 5.1 Confined/Unconfined Test Series
Two explosive materials were tested in this series. The
I principal one was the Black Powder manufactured by CIL in a
conventional processing plant. The second, was the jet milledI material., an in-process form of Black Po':der manufactured in a
pilot plant facility at IAAP. It is obtained by running a premix
of potassium nitrate,charcoal, and sulfur through an air agitated
jet mill. The jet milled particles are approximately 15 microns
in diameter.
I A typical test setup for this series is illustrated inFigure 2. The Black Powder or jet milled mixture was placed in
I cubical steel boxes for the confined tests. The steel boxes
were fabricated from 1/2-inch-thick steel plates which were
welded together at the edges. A hole, just large enough to
accept the booster, was drilled into the middle of one side of
the box as shown. The boxes were also loaded through this hole.
7
FASTAX
I CAMERA
I
6E- 40.71'IjPRESSURE GAGE
LOCATIONS
I E
I ICHARGE LOCATION 5E16.63'
04E 11. 75'
SECOND BLAST PAD -Q 6.79NOT USED DURINGTH-ESE TE STS -2.98'
DISTANCE TO
~FIRST GAGE
III FIDUCIAL
- - _MARKERS
Figure 1 TI']ST AREA
II8
.BLAGK POWDER
64 CARD1AVRA AO
4 JA
A
A Al
GROUND b 1
SIT RFAC!---
NA 4 Av
IDUPONT NUMIBER G 'BLASTING, CAP /"DA xI"TRY
BOOSTER
Figu~ 2 CONFINED/'JNCONFINED TEST SETUP
9 '
III
CurrugaLed cardboard boxes were used for the unconfined
shots. Holes were cut in the bottom of each box to accept the
booster. There was no top on the cardboard boxes. The cubical
fcardboard and steel boxes were sized so as to just accept thequantity of Black Powder being shot.
The Black Powder for the test series, where the effect of
confinement was determined,was ignited with a DuPont S65 electric
squib or a DuPont number 6 electric blasting cap and a 3/4-inch-
diameter by }-inch-long Tetryl booster.
Table 3 is a test schedule for this test series. Initiation
sources, confinement, and quantity of material tested are tabulated.
Two calibration tests CAL I and CAL 2 were performed to con'irm
the accuracy of the pressure measuring system. They consisted of
placing a 2 lb bare spherical C-4 charge on a szeel witness plate.
I Pressure and impulse data from these calibration shots were record-
ed and compared with previously established pressure-distance and
impulse-distance curves for C-4 explosive. A third calibration
shot, CAL 3 was conducted to determine the output of the Tetryl
booster.
Note that four of the tests in this series were conducted
l with the cubical Black Powder charge placed off the ground on awooden Platform. The standoff height, to the centroid of the
charge, was to be equal to one and one-half times the diameter of
an equivalent weight of a spherical TNT charge. This test condi-tion was discontinued because it was not possible to predict in
l advance the equivalent TNT weight of the charge.
a5.2 Booster Size and Shape Effects Test Series
This series of tests was performed to determine the effects~of booster type, size and shape, and Black Powder weight on TNT
equivalency. Typical test configurations are shown in Figure 3.
* Contained 0.2 grain initiating mix
10
±LI
*- 4 - -I r4 4r 4 - r4j4r4 - -- 4 A-t-4 C -
4 -d - $4- -4 4-r r r4-- e-W 4J4J -W4J - J 44J 4 W I W4 J -W-W -W ::
-,4
Cd
z
k OO O44- POOOOOOP t4 w-4 OHHHIa 0P- 0~~u 0 -4.I0000 -01- .4 0 - 4
N 44 -4CL P -4r-4 JOJP P 4Hr4 -4 A41 .- I r - r-4. 4.) ,-4 - 4 UJ (U-4
0 14 1- 4. dz 1 14 1 .z -1 1 %
d t 00 m 0; 110W0M 14 04 i -t-jI- ----- 1 ) r4r -- 1 ----A W rAr4rqQ 1 cC7
1 0 0I
14-ZIa) )
L i4 *f- -r -4 44 4r 4
BLACK POWDER
1b AAA 4 b 4AA CARDBOARD BOX
AA 0A GROUND
o -SURFACE
120 deg CONE, C-4 DUPONT NUMBER 6 Bz.A.' NC CAP
a. 120 deg CONE BOOSTER
BLACKPOWDER 1 ADOR O
7A4
CYLINDRICA DUON NUBE 66 oLS A
c~ OOSTER b. CYLNDRCA POLSTESUFiguE 3 BOSE EADSAPETS EU
IpA 12444
I
In all tests the Elack Powder was shot unconfined in cubical cor-
rugated cardboard boxes. Both conical and cylindrical shaped boost-
ers were used. The conical. shaped boosters were formed from C-4
explosive. The flat side of the 120 deg cone was in contact with
the Black Powder. The conical end of these boosters were buried
j in the sand as illustrated in Figure 3a. Cylinder shaped boosters
were located such that the Black Powder surrounded the booster
j as shown in Figure 3b. Booster explosives evaluated were Tetryl,
C-4, and 9404 PBX. The C-4 cylindrical boosters had a length to
diameter ratio of one. The Tetryl and PBX boosters had asoect
ratios of approximately 1/2 to 1. All the boosters were ignited
with a DuPont number 6 electric blasting cap.
The tests performed in this series are tabulated in Table 4
The sample tested and its weight are tabulated along with basic
Ibooster information. The majority of the tests were conducted withthe charge setting on a steel plate, this information is given in
5 Table 4 also.
|13 U!
-1
I!
II TAHjLE 4
UNCONFINED TESTS, BOOSTER EFFECT SERIES
Test Sample BoosterTest Steel
Weight WStetNumber Smple (ibs) Type Wlbs) Shape Bass Plate
BO- I Sand 25 C4 0.25 120 deg Cone NoI BO- 2 Sand 25 C4 0.25 120 deg Cone NoBO- 3 Sand 25 C4 0.50 120 deg Cone No
i BO- 4 Sand 25 C4 0.50 120 deg Cone NoBO- 5 Black Powder 25 C4 0.25 120 dep Cone NoBO- 6 Black Powder 25 C4 0.25 120 deg Cone NoBO- 7 Calibration Test -- C4 2.0 Sphere YesBO- 8 Black Powder 25 C4 0.50 120 deg Cone NoBO- 9 Black Powder 25 C4 0.50 120 deg Cone NoBO-10 Sand 25 C4 0.50 Cylinder No
, BO-l Sand 25 C4 0.50 Cylinder No! BO-12 Black Powder 25 C4 0.50 Cylinder No
BO-13 Black Powder 25 C4 0.50 Cylinder NoI BO-14 Black Powder 27 Tetryl 0.024 Cylinder Yea
80-15 Black Powder 27 Tetryl 0.024 Cylinder YesBO-16 Black Powder 75 C4 0.50 Cylinder NoI BO-17 Black Powder 75 C4 0.50 Cylinder YesBO-18 Black Powd.-r 75 C4 0.50 Cylinder NoBO-19 Black Powder 75 C4 0.50 Cylinder YesI BO-20 Black Powder 75 C4 1.00 Cylinder YesDJ-21 Black Powder 75 C4 1.00 Cylinder YesBO-22 Sand 7 C4 1.00 Cylinder YesBO-23 Sand 7 C4 1.00 Cylinder YesBO-24 Sand 75 C4 1.00 Cylinder YesBO-24 Sand 75 C4 1.00 Cylinder YesBO-25 Sand 75 C4 0.50 Cylinder YesBO-26 Sand 75 C4 0.50 Cylinder YesBO-27 Sand 75 C4 1.50 Cylinder YesBO-28 Sand 75 C4 1.50 Cylinder YesBO-29 and 75 C4 1.50 Cylinder YesBO-30 Black Powder 75 C4 1.50 Cylinder Yes
BO-31 Black Powder 75 C4 1.50 Cylinder YesBO-32 BL ck Powder 25 C4 1.00 Cylinder Yes
BO-33 Black Powder 25 04 1.00 Cylinder Y~sJBO-34 Sand 25 PBX 0.54 Cylinder YesBO-35 sax-i 25 PBX 0.54 Cylinder Yesj'BO-36 Black Po%u:A 25 PBX 0.54 Cylinder YesBO-37 Black Powder 25 PBX 0.54 Cylinder YeaBO-38 Sand 150 C4 3.00 Cylinder YesB0-39 Sand 150 C4 3.00 Cylinder YesBO-40 Black Powder 150 C4 1.50 Cylinder YesBO-41 Black Powder 150 C4 3.00 Cylinder YesBO-42 Black Powder 150 C4 3.00 Cylinder YesBO-43 Sand 25 C4 0.5 Cylinder Yes
.4
*BO is shot designation reference.
14
I5. TNT EQUIVALENCY TEST RESULTS
Summary tables listing shots fired according to test condi-
tions are shown in Table 5 for Black Powder and 'fable 6 for sand
tests. Appendix A (Volume II) contains a tabulation of a! raw
test data in terms of the peak pressure and impulse at eac-. of the
I six gage station locations. Appendix A also has these data ,.lotted
in the form of curves of pressure and scaled impulse as a function
j of scaled distance. The scaled distances and scaled impulses shown
for the data points are based on total charge weight, and have not
been adjusted to take into account the weight of the booster ex-
plosive.
Figure 4 is a typical summary curve of pressure-impulse data
for 25 lb charges of Black Powder. The curves shown in the anpen-
dix however, have results of each test plotted on a separate sheet.
It is displayed in this manner so t At comparisons can be made be-
tween different test conditions by superposing any combination of
curves of interest.
The TNT peak pressure and impulse e uivalencies are obtained
by determining the weight of TNT that would produce the same _k
pressure (or impulse) at the same distance as a given Black Powder
charge. It is the ratio of this weight of TNT to the weight of
Black Powder (wt TNT/wt Black Powder) that defines the TNT equiv-
alency. Thus, for example, if the TNT pressure equivalency is
10 percent.,1 lb of TNT would give the same overpressure at the
same distance as 10 lbs of Black Powder. The reference curves for
TNT are based on hemispherical surface burst.
A typical summary curve of pressure equivalency as a functionof scaled distance for 25 lbs of Black Powder initiated by various
booster weights is shown in Figure 5. A cross plot of these data
in terms of pressure equivalency as a function of booster weight,
at selected scaled distances, is shown in Figure 6.
Appendix B (Volume II) is a description of the procedure used
to calculate TNT equiva]encies and includes a sample pro-,'e. Ap-.endix C contains the computed values of pressure and im.ulse eoutv-
a lency.
15
(144
U,(
0 Nl44 -t
CO))
- -4
-4 (1)144
00
- -4
-4 IL 44 LIC4 4 o U
4)) AQ4-
o4 --t L d
r(n
u~. 4.4
00 It -44
v41
w 4 C) )4 ( )W E-4-4 - co UP
r-4-04.) f4
~zC; I () C) J ) 4
ci 4 9
P.. Ai 4-i
4 44 ) 14 b5v-I >1 4.W 4) r4
m 0
u L) a) 4-0 0
k4,4 -A w 14 -A
C: :j .0) 4 0
r 16L olcr
-- I 0
0' 00
CNr-4I
C1 0'I ~2fl
IW ' I
r4 Lf2
CI "0 4.X.)
I 04
E-4-
IC14
M cc0 Lr00 -00
I-4~L~r-4
Lr) 4-)
Iu 040
4-Q) 0~
00))
C'-))
LJLn
- 0
17
II
102 -rrI
771
. .4
10 100
-,- -
BOOSTER WT(ib)
! 0.50
Io 0 0._ 25 - o
--O.024
I 4 "II j. 10 J- __ L _,J.._":.
SCALED DISTANCE, R/W I1 3/
~Figure 4 PRESSURE AND SCALED IMPULSE FOR VARIOUS BOOSTER
WEIGHTS, 25 LB BLACK POWDER
I.- N 1
100 I I 111111
I BO-32,33 SP
I (BP 259 1.0)
I CON-3,4,5,(BP 27, .024)
I BO-36,37(BP 2510.54)c
1.0 '00BO-8,9,12,1310 (BP 25,.0.5)
I ci) BO-5, 6
z (BP 252.25)
BO-14,15 SP
i (BP 25,.024)
9404 PBX
0.11 a I J U
1 10 1.00SCALED DISTANCE, -A
p
Figure 5 EFFECT OF BOOSTER WEIGHTl ON TNT PRESSUREEQUIVALENCY, CONFINED AND UNCONFINED25-27 LB BLACK POWDER
LI 19
.10
I
CONINEDI I I A I I I I 1
I 2
~I
101
I UNCoNFINED
2
,3. 15
10 .5Ij
<>.J
I =2:
I -i0_i,-
10-
1 01I i ,ili t it I i Ii i i i I
0-2 10-1 100
I BOOSTER WFIGHT, pounds
Figure 6 TNT PRESSURE EQUIVALENCY OF 25 LB BLACK POWDER,I I AS A FUNCTION OF BOOSTER WEIGHT, FOR SELECTEDSCALED DISTANCES,
3 20
Li
g Equivalencies are given in tabular and graphical form. The pres-
sure and scaled impulse shown in the tables are based on the best
first or second order polynomial curve fitted to the data points,
as described in Appendix B. The scaled quantities, i.e., impulse
and distances, are based on the total charge weight which incli.Je .,
I a correction for the booster weight. The curves of equivalency "as
a function of scaled distance are plotted so that data from one
I initial test condition are shown on each page. This allows the ,
reader to make comparisons, other than those described in th A : -
port, by superposing any combination of curves.
In addition to equivalencies being calculated according tJ
points on the curve fitted to the pressure and impulse data, ca]-
culations of pressure and impulse equivalency were also made fOr
each of the measured data points. Because there was some scatter
I in the raw data, which is amplified when equivalencies are calcu-
lated, the data point-by-point results are not considered as usefulas those based on the fitted curve. However, for the sake of cm-
pleteness, the equivalencies based on the raw data points are given
in Appendix E, Volume II.
6.1 Overview of TNT E uivalenc Test Results
Inasmuch as tMe TNT equivalency of Black Powder was found tobe dependent upon distance from the charge, the weight of the Black
j Powder, the degree of confinement and the weight and type of explo-
sive booster used to initiate the Black Powder, a single number
need not be used to express the TNT equivalency of Black Powder.
In addition the impulse equivalency is always greater than the pres-
sure equivalency. However, when all of the equivalency data ac-
quired on this program are plotted as a function of booster weight,for selected scaled distances, all data fall within two rather well
I defined regions, one for pressure and the other, impulse. The en-
velope as well as the data points are shown in Figures 7, 8 and 9.
I The maximum value of impulse equivalency occurs at scaled distances
=2 and is less than 43 percent. The maximum value for pressure
i* equivalency is 24 percent at = 7.
21
I
i00 , , I l i ii I, I 111"111
- IMPULSE / /
-© /I I
_- /1 10
1000
PP0
0 )P PRESSUREz
I- UNCONFINED CONFINED
x 8 lbs o 8 lbs
, 25 Ibs 25 Ibs
+ 75 Ibs o 75 ibs
I 0 150 lbs @ 150 lbs
010.01 0.i .1
BOOSTER WEIGHT, pounds
Figure 7 ENVELOPE OF PRESSURE AND IMPULSE EQUIVALENCYAS A. FUNCTION OF BOOSTER WEIGHT FOR ALL TESTS,
I SCALED DISTANCE N=2
I 22
100 T
Ip
IMPULSE A
-9- _
11 0 0 I
II
®Rp
/C....' - ..)
~PRES SURE
8 ibs
1 "
1 25 ibs+ 50 lbs UNCONFINED
I - o 150 lbs
I ( )25 lbs
G75 lbs CONFINEDI ® 150 lbs
I 0.1 0.0 IA I i
I BOOSTER WEIGHT, pounds
Figure 8 ENVELOPE OF PRESSURE AND IMPULSE EQUIVALENCYAS A FUNCTION OF BOOSTER WEIGHT FOR ALL TESTS,SCALED DISTANCE X=5
23
.. ....L k* .. '+*u''u> lill ' ,-
',,7 ',=, . . L . ' ," . . .. . .. . .
100 I I
I
10 p
I p
oe x 8lbs0 125 ibs
+NCONFINEDF4+ 75 ibs
0 150 lbs
8 lbs
25 lbs CONFINEDe75 Ibs
i @ 150 Ibs
0 .1 1 1 1 1 1 1 1 1 I i0.01 0.SAu
~BOOSTER WEIGHT, pounds
Figure 9 ENVELOPE OF PRESSURE AND IMPULSE EQUIVALENCYAS A FUNCTION OF BOOSTER WEIGHT FOR ALL TESTS,SCALED DISTANCE ?=10
24
II
The impulse equivalencies are generally at their maximum at scaled
I distances -- 2, and then decrease with distance. On the other
hand the pressure equivalencies increase with scaled distance
reachin a maximum value at scaled distance of between 7 and 10
f/3 and then decrease.
knother data summarizing method is to plot the data in the
form of equivalency as a function of weight ratio, i.e.,,the ratio
of booster weight to Black Powder weights, Figures 10, 11 and 12.
This approach to interpreting the data provides guidance as to the
combined effects of booster and Black Powder weights. For the same
I weight ratios, the TNT equivalencies for 75 and 150 ib charges areessentially equal, whereas 25 lb charges have lower values.
25.
Af
IIII
II
I
~I
25
100 - 11111 1
10
040
IiWWI
D,
1 @25 lb with9404 PBX Booster
x 8 lbPRESSURE * 25 lb
IMPULSE o 150 lb
I CONFINED
0.10.1wih 75l
0.0 0.11
WEGH RATIOoote x 100, percentFigre 0 ~Ueih Black Powder
Figre 0 PESSRE ND MPUSEEQUIVALENCY AS A FUNCTIONOF WIGHTRATIO, FOR ALL TESTS, SCALED DISTANCE
; =21
26
I100I I I 1"'11 I 00,1
I I + " .
I f.101
z
0'
( 25 lb with
i -9404 PBX BoosterI lX 8 lb"
-__ PRESSURE * 25 lb
i + 75 lbIMPULSE O 150 lb
-Z CONFINED
II 0.1 I I I I II 1 i I I i ia I
0.01 0.1 1.0
eWEIGHT RATIO, Hitbooster x 100, percentweight Black Powder
I Figure 11 PRESSURE AND IMPULSE EQUIVALENCY AS A FUNCTION
OF WEIGHT RATIO, FOR ALL TESTS, SCALED DISTANCE?,=5
27LI .
III
i ~100 j , , I , , I I I I I I IIJ ' "
1 10
II o,. A m4 -
| ,
CY ,
I @ 25 lb with !
1 9404 PBX Booster i
I - _
x 8 lb1 25 lb w
-. PRESSURE + 75 lbo 150 lb
IMPULSE
I PA CONFINED
r0.1 lI0-0.01 0.1 1
WEIGHT RATIO, weight b2oster x 100, Percentweight Black Powder
I Figure 12 PRESSURE AND IMPULSE EQUIVALENCY AS A FUNCTIONOF WEIGHT RATIO, FOR ALL TESTS, SCALED DISTANCEI=10
28
i I -
I
I7. EFFECT OF VARIOUS PARAMETERS ON TNT EQUIVALENCY
In this section the effects that various test parameters
have on the resulting Black Powder TNT equivalence are discussed.
i The factors that have an effect are the degree of confinement,the weight of the Black Powder charge, the weight of the explosive
booster, and the type of explosive used for the booster. The
explosive booster shape had no effect on equivalency for the two
shapes evaluated. A limited number of tests were carried out
S I on the jet milled material and comparisons were made with thebehavior of the Black Powder.
I Each subsection contains a discussion of the effect and
the data are presented in graphical form. In a few instancesa figure appears in more than one subsection. This was done foreasier reading.
The notation used to identify each figure is as follows.
Con 1, 2 (BP 8, 0.024) means tests Con 1 and Con 2 consistingj of a confined 8 lb charge of Black Powder initiated with an 0.024
lb booster. If the initials SP follow the shot aumber it means
the charge was placed on a steel plate. Thus BO 41, 42 SP
(BP 150, 3.0) refers to tests BO 41 and BO 42; each test consis-
ted of an unconfined 150 lb charge of Black Powder resting on a
steel base plate and initiated with a 3.0 lb C-4 booster.
7.1 The Effect of Heavy Confinement on TNT Equivalency
One of the most significant findings is that the TNT equiva-lency is affected by the degree of confinement. Four levels of
increasing confinement were evaluated:
a. No confinement; the sample was contained in a card-board box placed 7 inches above the ground on a woodpedestal.g b. Light partial confinement; the sample was contained
1 in a cardboard box placed on the ground, hence thebottom face is considered confined by the earth surface.
c. Heavy partial confinement; the sample was contained
in a cardboard box placed on a steel plate whichrested on ground.I Ii
29
~~ .... . .A .-~ AA < .AhA . ......S
r
II
d. Heavy confinement; the sample was contained in a steel3box, having 1/4 inch wall thickness, placed on the
ground.
It is clear from the results of a series of seven tests on
27 lbs of Black Powder initiated with a 0.024 lb booster that a
confined charge has a higher blast output than unconfined Black
1 Powder charge. This effect is emphasized in comparing the above
results with three additional tests on 27 lb confined Black Powder
charges where the charge was initiated with a DuPont S65 squib
containing 0.2 grain of initiating mixture. Even with such a mild
[ form of boostering, toe TNT equivalency was greater for the con-
fined squib-initiated charge than for unconfined Black Powder
initiated by a 0.024 lb Tetryl booster.
Figures 13 and 14 are summaries of the effects of confinement
for 27 lbs of Black Powder in terms of TNT equivalency. The raw
data for this summary graph are found in the appendices (Volume II).
4 more dramatic comparison is between shots Con 9 and 10,
140 lb charges initiated with 0.024 Tetryl booster and shot BO 40
an unconfined 150 lb sample initiated with a 1.5 lb booster. The
iTNT equivalencies are greater in the coiLfined tests. When Con 9and 10 are compared with unconfined 150 lb Black Powder initiated
with a 3 lb booster, BO 41 and 42, the confined tests again yield
higher pressure and impulse equivalencies except at scaled distances
less than 3 (A3). Thus it is clear that confinement is an im-
portant and sensitive parameter. These comparisons can be seen in
Figures 15 and 16. Similar effects of confinement can be seen in
I Figures 17 and 18 for 75 lb charges.
IIIII 3
- A,,J
100 .v'
BO-32 33 SP(BP 25, 1.0)
CON- 3,4,5,(BP 273. *024)
(AP 27 ,SQ)
0.. BO-5, 6(BP 25,.25)
BO-14 15 SP(BP 259.024)
zero )re, sure equivalen,-y Unc 1, 2 (BP27, O. 4)
*9404 PBX
3.10 100
5CALED DISTANCE, X%
F iyur e 1.3 EFFECT OF CONFINEMENT AND BOOSTER WEIGHTI ON TNT PRESSURE EQUIVALENCY, 25-27 LBBLACK POWDER
31
1100 -T . ~
BO 36$37 SP (BP 25,0.54)
IBO-32 33 SP(BP 25,1.0)
I CQN-394,15(BP 27,,.024)
BO- 8 9 12,13_____________________ (BP ~5 0.5
10BO- 5 6(BP H5,0.25)
Z SQ-I1 2,3~L4 (BP D7,SQ)
BO-14, 15 SP(BP 25, .024)
zero impulse equivalency Unc 1, 2 (BP27, 0.24)
~9404 PBX booster
I x110 100
SCALED DISTANCE, x~VI
Figure 14 EFFECT OF CONFINEMENT AND BOOSTER WEIGHT ONTNT IMPULSE EQUIVALENCY, 25-27 LB BLACK
POWDERL. 32
100 1 I',li
F ICON-9, 10 (BP 140,.024)
BO-41,42 SP
10 (BP 150,3.0)j
10 H0O4 1P
IR 15,15
010
5 SCALED DISTANCE, X1 xp
Figure 15 THE EFFECT OF BOOSTER WEIGHT AND CONFINEM'ENT ON
I TNT PRESSURE EQUIVALENCY, 140 AND 150 LB BLACKPOWDER
33
I
BO-41.42 SP (BP 150,3.0)
CON- 9 10(BP 04o,.o)
V!
BO-40 SP (Bp 150,1.5)
10
~I
a
II
0.1A
1 10 100
I SCALED DISTANCE, XI
Figure 16 THE EFFECT OF BOOSTER WEIGHT AND CONFINEMENT ONTNT IMPULSE EQUIVALENCY, 140 AND 150 LB BLACKPOWDER.
1 34
II
1 -00 I 5 1
BO-30,31 SP(BP 75,1.5)
10BO-20,21
t(BP 7i $ 1. 0)
\BO-17,19 SP(BP 75,0.5)
, X BO 16,18 (BP 75,0.5)
CON-6,7,8 (BP 64,.024)
jf
10lo
IIII
I0.1 = i a i anal innsi
1 10 1oo1 SCALED DISTANCE, X
U pFigure 17 EFFECT OF BOOSTER WEIGHT AND CONFINEMENT
ON TNT PRESSURE EQUIVALENCY, 64-75 LBBLACK POWDER
35
1 100
IBO-30,31 SP (BP 75, 1.5)
I00BO-20,21
~lI (BP 75,1.0)
I10 BO-16 18 (BP 75,0.5)
CL CON-6,7,8 (BP 64,.024)
rz
10 ~1
I SCALED DISTANCE, X1
3Figure 18 EFFECT OF BOOSTER WEIGHT AND CONFINEMENTION TNT IMPULSE EQUIVALENCY, 64-75 LB
BLACK POWDER
36
7.2 The Effect of a Steel Base Plate on TNT EquivalencyI
In an effort to maintain control of the surface on which the
explosive sample is placed, a steel base plate was found to be
f necessary. This was considered especially important since some of
the initial tests were carried out when the ground was frozen.
Thus in the morning the charges would be placed on hard frozen
ground, but by tthe end of the day the ground would not only be
thawed, but it would be of a very loose texture after repeated
testing. The effect of ground hardness on equivalency was not
initially apparent, hence, many tests were carried but with the
sample placed directly on the ground.
The best direct comparison of the effect of the supporting
base plate can be seen in tests on 75 lb Black Powder using a
0.5 lb C-4 booster, shots BO 16 and 18, that were placed on the
ground, and shots BO 17 and 19 that were placed on a steel plate
whose top face was flush with the ground. The TNT equivalencies
were higher for BO 17 and 19. A summary figure showing the TNT
equivalency of BO 16 and 18 compared with BO 17 and 19 can be
seen in Figure 19.
Two additiorl sets of tests were carried to test the effect
of the charge supporting surface on equivalency. These tests were
on 27 lb Black Powder initiated with a 0.024 lb Tetryl booster.
Tests BO 14 and 15 were carried out on a steel plate and shots
Unc 3 and 5 were placed directly on the ground. However, we
cannot make a quantitative comparison between these tests, since
for both shots Unc 3 and 5 the gage system was overdriven result-
ing in measured values that are less than the actual values.
Similarly, Figures 20 and 21 summary curves for 75 lb charges
show generally higher values of equivalency when steel base plates
are used.
37
BO 1008
j BO-BO,16 SP (BP 75,0.5)
01
1 1 10
SCALED,1 (BPACE 75,0.5Fiu r gCMAIO EWE TE AEPAEADGON
SUFC NTH N QIVLNYO BAKPWE
C'38
r
_ CONFINED UNCONFINED
- X=1i0 x=5
X=105
X=5 X=5X X=15
C i0 - _....o -=
Fo X= 10 =
>4=2
, i
C14
I
o NO STEEL PLATE
* STEEL PLATE
!0.1 I I I l 1i I I I I iIII
1 0.01 0.1 1.0
BOOSTER WEIGHT, pounds!Figure 20 TNT PRESSURE EQUIVALENCY OF 75 LB BLACK POWDER
AS A FUNCTION OF BOOSTER WEIGHT, FOR SELECTEDI SCALED DISTANCES
39I'_ .- ' q i
. 7 ... .. . . ... . .. . .. , . , . .. .. .. ... . . . .. .. . .
100 , , I I 1, , I ' '1 I1
CONFINED UNCONFI NED
X=2
X=15 X=15
X=10 -X=10x =5
-X=2
10
-4
I-o STEEL PLATE
0 NO STEEL PLATE
10.1] 11 - L I I110.01 0.1 1
BOOSTER WEIGHT, poundsIFigure 21 TNT IMPULSE EQUIVALENCY OF 75 LB BLACK POWDER
AS A FUNCTION OF BOOSTER WEIGHT, FOR SELECTEDI SCALED DISTANCES,
40
Li?
!?, I
7.3 The Effect of Small Standoff Distance Abovegroundon TNT Equivalency
Three tests on Black Powder were carried out with the charge
placed on a wood platform 7 inches above the ground. The reason
for this elevation was so that comparisons could be made with workcarried out elsewhere where the charges were placed at a height
above the ground such that the standoff height to the centroid ofthe charge, was equal to one and one-half times the diameter of
an equivalent weight of a spherical TNT charge. Since there wassuch a wide range of TNT equivalencies for Black Powder, dependingupon the initial test conditions, it was not possible to predict
' with any degree of confidence in advance of testing what the appro-
priate height aboveground should be. Hence this approach was aban-doned after three tests, Unc 1, 2 and 4. These tests resulted in
essentially zero TNT equivalency. The results of tests Unc I and 2can be compared with Unc 3 and 5 which were tests directly on the
ground using the same charge weight and booster, 27 lb Black Pow-der and 0.024 lb Tetryl booster. The pressures and impulses wereconsiderably greater for charges placed on the ground (Unc 3 and 5)
although the exact values of the blast parameter for these testsare not known because the gage system for Unc 3 and 5 was over-driven, only that the actual pressures were higher than those mea-sured. Thus it is clear that the blast output is very sensitive
to the degree or extent of confinement.
7.4 The Effect of Black Powder Weight on TNT Equivalency
When the Black Powder is confined and the booster size iskept constant, the TNT equivalency increases with increase incharge weight. This effect is illustrated in Figure 22 and 23
curves showing the pressure and impulse equivalency, as a functionof scaled distance. The data for 8 and 27 lb charges show that
the pressure equivalency for 8 lb charges is much less than for
27 lbs up to a scaled distance N = 7, at larger distances thevalues are essentially equal. The impulse equivalencies areapproximately the same for 8 and 27 lb charges.
41
rI
100 - - - -
- CON- 9, 10
(BP 140,.024)CON-6.7$8- (BP 64,$.024)
CON- 1,2I - /-- (BP 8,. 024)-
10 CON-3,4.5o - (BP 27,.024)--
~SQ-4 5"C(JM 170SQ)
I z (BP 7SQ)
I CON-1 12= (JM 27'.024)
III
Im
I "JM = JET MILLED
BP = BLACK POWDERII . p i pppi i i I m i i
10 100
SCALED DISTANCE, Xp
Figure 22 EFFECT OF CHARGE WT ON TNT PRESSURE EQUIVALENCY;CONFINED TESTS, SQUIB OR .024 LB BOOSTER INITIATION
42
1.00----
COON- 10 9
SQ-4 5- (JM 17 SQ)
c'm CON-3,4,5(BP 271.024)
10
(BP, SQ)
CON-IIL,32 (JM 27,.024)
10 10
CONFNEDESTSSQU BP R .2BC POWDTER
INITIATION
43
r1I
IThe data for unconfined charges, on the other hand, show
I ithe opposite effect, when equivalencies are compared on the basis
of constant booster weight. The larger unconfined charges re-
quired larger size boosters. Apparently, unless sufficiently
boostered the reaction does not grow. The heat generated is lost
to the environment faster than it is produced by the explosion.
Figures 24 and 25 show the comparisons between 25 lb charges and
75 lb charges initiated with a 0.5 Ib booster. Figures 26 and 27
illustrate these effects for charges initiated with 1.0 and 1.5 lb
boosters, respectiveiy.
The combined effects of charge weight, booster weight, and
degree of confinement is illustrated in the six sunmnary curves in
f ISection 6, Figures 7 through 12. Although it is clear that uncon-
fined charges have been underboostered, all of the data do fall
1 within the envelope shown in Figures 7 through 9 and the equiva-
lencies seem to level off. Then the weight ratio is increased,
* i.e., booster weight divided by Black Powder weight, the equiva-
lency increases, as expected.
I
III
III
I14
.10
1 10
z
I *9404 PBX
10.1 ' 'i'aiiU11.010
SCALED DISTANCE, XI 'p
Figure 24 THE EFFECT OF BLACK POWDER WEIGHT ON TNTPRESSURE EQUIVALENCY FOR ALL TESTS USING
0.5 LB BOOSTERS
1 45
rII1 100
BO-36 37 SP (BP 25,0.54)
BO-8,9,12,13 (BP 25,0.5)
F "
BO-16,18 (BP 75,0.5)
el a-BO-17,19 SP (BP 75,0.5)
I Cy
! -I
i__0 I0
SCALED DISTANCE, XI
Figure 25 THE EFFECT OF BLACK POWDER WEIGHT ON TNT IMPULSEF EQUIVALENCY FOR ALL TESTS USING 0.5 LB BOOSTERS
46
Li
I
1 100I IMPLS Bo-2o)21_- BO-32,33SP
I fBO- 32,$33 SP
(BP 25,1.0)
10 BO-2021 (BP 75,1.0)
- PRESSURE
Cy
'2
01
I
1 10 100
SCALED DISTANCE, XI, X p
Figure 26 THE EFFECT OF BLACK POWDER WEIGHT ON TNTEQUIVALENCY FOR ALL TESTS USING 1.0 LB BOOSTERS
47
I
I100I I 111
I 1-004-0--: IMPULSE
BO-30,31 SP
(BP 75, 1.5)
PRESSURE
) BO-40 (BP 150,1.5)
I
IIII
I
1 10 100
I SCALED DISTANCE, ; I 'p P
i Figure 27 THE EFFECT OF BLACK POWDER WEIGHT ON TNTEQUIVALENCY FOR ALL TESTS USING 1.5 LB BOOSTER
48
I 7.9 The Effect of Booster Weight on TNT Equivalency
IFor unconfined Black Powder charges, it was found that
an increase in booster weight resulted in an increase in TNT
Iequivalency. This was also true in confined charges, whereonly squib and 1igm (0.024 lb) boosters were used. For the con-
fined tests the equivalencies were comparable to that of uncon-
fined cnarges using boosters that were almost 10 times heavier
in weight. These effects are summarized in Figures 28 and 29
Ifor 25 lb charges, Figures 30 and 31 for 75 lb charges, and
Figure 32 for 150 lb charges.
The figures reflect the complexity of the behavior of Black
Powder, and indicate that there are interactions between booster
Iweight, scaled distances A, and degree of confinement (which isillustrated in the figures for tests on 75 lb quantities). If
Ione does not wish to use maximum values for design and quantity-distance purposes, then the value of equivalency associated with
a given weight and confinement level, for protection at a required
distancecan be determined from the data presented in this report.
4III
II
III 49
LW
CONFINED__ _CONFINED
X=1
00 x=2O
xX=15A X= 5
C.)
o 9404 PBX BOOSTER
I 0 C-4 BOOSTER
I 0.01 0.11
BOOSTER WEIGHT, pounds
Figure 28 TNT PRESSURE EQUIVALENCY OF 25 LB BLACK POWDERAS A FUNCTION OF BOOSTER WEIGHT, FOR SELECTEDSCALED DISTANCES,
50
II
100 I iii
CONFINED UNCONFINED
I ~~X=2 1 / :.. 'i • X=5
X=15,1I -' +10,15,-
10
- -,
1 9404 PBX BOOSTER
I *C-4 BOOSTER
I0.1 L. I . I ,
0.01 0.1 1
*BOOSTER WEIGHT, pounds
Figure 29 IMPULSE EQUIVALENCY OF 25 AND 27 LB BLACK POWDERAS A FUNCTION OF BOOSTER WEIGHT, FOR SELECTEDSCALED DISTANCES X
.. •51
I I
100 , , , II
ICONFINED UNCONFINED
- o X- 1.0
-- x=5X =5x X-10
j.--=X- 5 X-5I 10 o.. .
I i X-15
X-15 - ~ X=2
xX-2i xX==
I
iCA
I i o NO STEEL PLATE
SSTEEL PLATE
0.1 i u l
0.01 0.1 1.0
BOOSTER WEIGHT, poundsIFigure 3 : TNT PRESSURE EQUIVALENCY OF 75 LB BLACK POWDER
AS A FUNCTION OF BOOSTER WEIGHT, FOR SELECTEDI SCALED DISTANCES
52
•1 0I1 1.00, s I 11' 1 I I I i-
ICONFINE D UNCONFI NEDIXX-
X- 10 =~X,,2
10
I _ "
0 STEEL PLATE
I • NO STEEL PLATE
IN0.1 I I i I l , I i
I0.01 0.1 1
BOOSTER WEIGHT, pounds
Figure 31 TNT IMPULSE EQUIVALENCY OF 75 LB BLACK POWDERAS A FUNCTION OF BOOSTER WEIGHT, FOR SELECTEDSCALED DISTANCES, x
I5
Ij 100 I i i ' 11l I I ( i "'l1 I i
k-1 =15 IMPULSE i=2
x =5 X=5, ,,.. <.- xp=5 i -
PRESSURE Xp=10.-5 xp=15
10 px 2
II
.4
i I I I ii i i i I I I i
O.U1 0.1
BOOSTER WEIGHT, pounds
Figure 32 TNT EQUIVALENCY OF 140 AND 150 LB BLACK POWDERAS A FUNCTION OF BOOSTER WEIGHT, FOR SELECTEDSCALED DISTANCES, 2
54
I
1 7.6 The Effect of Booster Geometry on TNT Equivalency
No differences in pressure or impulse were found when cone
shaped or cylindrical boosters were evaluated. The weight of
each shaped booster was the same. The aspect ratio, L/D, of the
cylinder was such that the surface area of the cylinder in con-
tact with the Black Powder was the same as the arua of the flat
face of the cone which was in contact with the Black Powder. The
reason for considering these two shapes is that work carried
out by other investigators showed that the conical boosters give
a very high initiating effect relative to their weight, for
boosters that are placed externally with the end surface in
contact with the acceptor charge. They found that the factors
that affect initiation of the acceptor charge are peak pressure
of the booster, duration of the boosters pressure pulse, and the
surface area of the booster in contact with the charge. The sur- bface area and duration are interrelated since they both depend
upon the weight of the booster. The referenced study did not
compare initiating effectiveness between booster charges placed
inside the acceptor with those placed on the outside. Thus tests
were carried out using cone shaped boosters placed in contact
with the bottom surface of the Black Powder and cylinder shaped
boosters placed internally.
The effects of booster geometry were evaluated using 25 lb
unconfined Black Powder charges initiated with 0.5 lb boosters
of C-4. Shots BO 8 and 9 used cone shaped boosters. Shots BO
12 and 13 utilized cylindrical shaped boosters. A summary of
the TNT equivalency data for pressure and impulse can be seen in
Figure 33.
IJohansson, C. H. and Persson, P. A., "Detonics of High Explosives"
Academic Press, 1970.
L | 55
100
IMPULSE
BO-12,13 (CYL) - E~AVERAGE
BO-8,9 (CONE) BO-8,9 (CONE)
10°= ."- /// k.AVERAGE"
.BO- 12,13 (CY'L,)
PRESSURE
E-;I
I0.1 I i I l, i I i 11111
1o 100SCALED DISTANCE, XI , Xp
Figure 33 THE EFFECT OF BOOSTER GEOMETRY ON TNT EQUIVALENCYOF BLACK POWDER
lb 56
* I
7.7 Effect of Type of Explosive Used For Boosters, on Equivalency
I To determine the effect of type of booster explosive on
output of Black Powder, unconfined 25 lb Black Powder charges
were initiated with C-4 (BO 12 and 13) and 9404 PBX (BO 36 and 37)boosters weighing 0.5 lb and 0.54 lb respectively. The tests
using 9404 PBX boosters, also used steel base plates, whereas
the tests charges using C-4 boosters were placed on bare ground.
Thus this comparison involves the interaction of both booster type
and steel plate. Other comparisons on steel plate effects alone
shot BO 16, 18, and BO 17, 19, Figure 19 showed that there is anincrease in pressure and impulse equivalency when steel plates
are used. However, the effect of using 9404 PBX booster is much
greater than that attributed to use of steel plate alone. This
can be seen in Figures 34, 35, and 36 where the TNT equivalency
is plotted as a function of weight ratio, i.e., the ratio ofbooster weight to Black Powder weight. Each of the three figures
is for a different scaled distance. In these curves no distinc-tion is made between those tests using a steel plate and those
tests fired on the ground. Clearly the 9404 PBX data fall abovethe other 25 lb charge data. Similar effects can be seen in
Figures 37 and 38, which are plots of equivalency as a function
of booster weight, at selected scaled distances for 25 lb BlackPowder. The data points for 9404 PBX boosters fall above the
curves for C-4 boosters.
Although the higher detonation pressures from 9404 PBX
boosters results in an enhancement of the initiating effects ofBlack Powder, as compared with C-4 boosters of the same weight,it is not suggested that 9404 be used for future investigationssince the cost of the PBX explosive is prohibitive for routine
use, and the same results can be obtained by using a larger
i booster of C-4 explosive.
Li 57
I
IOI I IT T I I I I'
I
0
G)
I
21.00Gi /
-o 61
- 251b with9404 PBX Booster
x 8 ibI PRESSURE * 25 lb
+ 75 lb
I IMPULSE o 150 lb
& CONFINED
0.i. I . i Ii'ii ,
0.01 0.1 1
I WEIGHT RATIO, weight booster x 100, percentweight Black Powder
Figure 34 PRESSURE AND IMPULSE EQUIVALENCY AS A FUNCTION
OF WEIGHT RATIO, FOR ALL TESTS, SCALED DISTANCE
58
I
II
1
10 A
Uz
251b with
9404 PBX Booster
I __x 8 lb____.. .. PRESSURE * 25 lb
+ 75 lbIMPULSE o 150 lb
ICONFINED
I0.1 n il I i m iI tl I
0.01 0.1 1.0
WEIGHT RATIO, weight booster x 100, percent
weight Black Powder
Figure 35 PRESSURE AND IMPULSE EQUIVALENCY AS A FUNCTIONOF WEIGHT RATIO, FOR ALL TESTS SCALED DISTANCE
59
I
I
I " A
I100
I with
I _ 9404 PBX Booster
- • 25 lb"
-PRESSURE. + 75 lb_
I o 5 i
IMPULSE 0 10l
i CONFINED-
!U
0.1
I0.01 0.1I
SWEIGHT RATIO, weight booster x 100, Percent
'weight Black Powder
SFigure 36 PRESSURE AND IMPULSE EQUIVALENCY AS A FUNCTION
OF WEIGHT RATIO, FOR ALL TESTS, SCALED DISTANCEI60
i 6
H ... A .. , , ... .. ... . .. .............. i
I
100 . "' T
- CONFINED UNCONFI NED
Ii
Ir 15X=5
100
l=!00 X=2
1 1-0>4
-4 0 9404 PBX BOOSTER
I - • C-4 BOOSTER
I
0.1 I , iiil I I I I itIl0.01 0.1 1
BOOSTER WEIGHT, pounds
Figure 37 TNT PRESSURE FQUIVALENCY OF 25 LB BLACK POWDER3AS A FUNCTION OF BOOSTER WEIGHT, FOR SELECTED
SCALED DISTANCES,
Li 61
I!
1.00 li,I"- CONFINED UNCONFINED
X-2j X-2
SX=LX=10015
sX-5
I -I
o-409404 PBX booster
I *C-4 booster
I
0 .1 I I I I , I._
0.01 0.1 1
BOOSTER WEIGHT, pounds
Figure 33 IMPULSE EQUIVALENCY OF 25 AND 27 LB BLACK POWDERAS A FUNCTION OF BOOSTER WEIGHT, FOR SELECTEDSCALED DISTANCES 'A
62
i.I
There are several factors that affect the initiation of
Black Powder (or any acceptor material) by a shock wave. TheyUi
are: the peak pressure of the disturbance; its duration; and
the surface area of the initiation source that has a direct ac-
tion on the acceptor. The shock wave need not be produced by a
high explosive booster. It can be produced by impact of a foil
for a thick plate. If the foil and plate are of the same mate-
rial and velocity then the pressure at the acceptor face is
the same, but the duration is much smaller for the foil than it
is for the thick plate. Similarly, we can increase the duration
of the pulse by increasing the weight of the booster explosive--
in tests where the booster is in contact with the acceptor mate-
rial. It has been shown for three different explosive materials,
jusing test results of a number of investigators, that the shock
sensitivity of an explosive can be characterized by two values;
peak pressure and duration of pulse. Thus in the work reported
here the peak pressure of the donor charge was constant (C-4
boosters were used in the majority of the tests). The duration,
or pulse widths, were increased by using booster weights ranging
from 0.024 to 3 lbs. The tests using 9404 PBX, which has a higherdetonation pressure than C-4, gave the same results as tests usinga larger weight C-4 booster.
The same results could be obtained by using a booster witha lower peak pressure, but longer pulse duration. By using lower
I pressure boosters (e.g., low density Tetryl or nitroguanidine),or impact of flyer plates we would still be able to map out the
I possible reaction intensity levels that the Black Powder couldachieve, and this would be the same as already achieved with C-4
Iboosters.
I
I 63
I]
7.8 Comparison of the TNT Equivalency of the Jet Mill Productand Black Powder
A total of six tests were carried out on 27 lb charges of
g the jet milled product. The output of the jet milled product is
I lower than Black Powder both for confined and unconfined test con-
ditions, when charges are initiated with 0.024 lb (11 gm) Tetryl
Iboosters. These effects are illustrated in Figures 39 and 40.However when these materials are initiated by a squib (DuPont S65
i squib consisting of 0.2 grain initiating mix), the jet milled
material has a much higher impulse equivalency and a higher pres-
sure equivalency for scaled distances X>5. Figures 41 and 42
illustrate this effect. The only squib tests were for confined
charges. When Black Powder was squib initiated, shots SQ 1, 2, 3,
the blast output was lower than when initiated with an 0.024 lb
Tetryl booster, as expected. One explanation for the unusual
behavior of the jet milled material is that the squib caused a
deflagration reaction in the material. Upon reflection of the
deflagration pressure wave from the steel confining surfaces an
increase of pressure of high enough intensity caused retonation;
a detonation propagates back into the already heated and disturbedjet milled product. Whereas the Black Powder was promptly initi-
ated to a low order detonation reaction. It is believed that
Black Powder and its in-process forms.
III
II ~----.-~6
10I I
>: CON-1,
w (BP 27,.024)
10 100
LB CHAGE, .24LBOOTE(365.04
II
100
I
ICON- i, 2(BP 8,.024)
,CON-3,4.5(BP 27,.024)I_
10 ~CON- 11 9 14(3M 27,.024)
BO-1.5 SP
> (BP 27,.024)
z K UNC- 9
(JM 27,.024) "
$4
I BP .- BLACK POWDER
JM = JET MILLED
II
~~~~0 .1 l lI ,, ,10 100
[ SCALED DISTANCE, XII
Figure 40 COMPARISON BETWEEN THE BEHAVIOR OF BLACK POWDER ANDTHE JET MILLED MATERIAL AND THE EFFECT OF CONFINE-
MENT ON IMPULSE-EQUIVALENCY FOR 8 AND 27 LB CHARGES,0.024 LB BOOSTER
I66
II ~oo 1iIq
ICON- 9 10(BP 140.024)0 "0ON-6 7,8J
CON- 1,2
10CO-34.
1S\ - 1 20
. / \ CON- 11, 12I
I0
JM = JET MILLED
~BP - BLACK POWDER.1
I I10 100
SCALED DISTANCE, Xp
I5 ~p4I
Figure 41 EFFECT OF CHARGE WT ON TNT PRESSURE EQUIVALENCY;CONFINED TESTS) SQUIB OR .024 LB BOOSTER INITIATION
E, 67
I
1 100
ICON- 9 10 CON-6 7P8I(BP 140O,.024) (P6'04
SQ-4 ,5F C(OB(3M 27 SQ)
CON- 1,2
(BP 8,.024)
CON-3 4,5
1 10 (BP 2 ',.Q24)
UU U SQ-1,2.3
I a~a..(BP27, SQ)
a CO14-I1$12 (JM 27,.024)
- J3M - JETr MILLED
BP - BIACK POWDER
0.1
110 100
ISCALED DISTANCE, XI, x p
Figure 4 2 EFFECT OF CHARGE WT ON TNT IMPULSE EQUIVALENCY;I CONFINED TESTS, SQUIB OR .024 LB BOOSTERINITIATION
68
I7.9 The Significance of the Convex Shape of the Pressure
Equivalency Distance Curves and the Effect of Errorsin Measurements on the Computed Values of Equivalency
I The pressure equivalency of Black Powder varies with dis-
tance. The pressure-distance equivalency curves are generallyconvex in shape. They reach their maximum at a scaled distanceof between 7 and 10 ft/lb1 /3. This effect can be traced back
to the shapes of the pressure-distance curves for TNT and Black
IPowder. The TNT pressure curve is concave in shape, whereasthe Black Powder curves are generally opposite, or convex, inIshape. This effect of pressure equivalency varying with dis-tance has also been observed for solid rocket propellants, and1 may be due to the slower rate of reaction of Black Powder orpropellants, as compared with TNT. The impulse equivalency onthe other hand does not vary substantially with distance. It is
essentially constant, since the impulse-distance curve for BlackPowder is patallel to the impulse-distance curve for TNT.
5 it must be recognized that since the computations of equiv-alency involve cubing the ratio of two scaled distances, an
error in a Black Powder measurement would result in an error ofthree times that magnitude in the equivalency value. Hence, if
we assume a 5 percent error in J, resulting from a 10 percent er-1 15ror in measuring pressure, then the computed equivalency value may~be in error by as much as 15 percent. Thus, if the TNT equivalency
was computed to be 30 percent it could, assuming a 5 percent errorin ?., be between 25.5 and 34.5 percent equivalency.
The error or uncertainty was minimized by each test conditionbeing carried out in duplicate or triplicate. The pressure (orimpulse) for each distance was averaged and a first or second orderpolynomial curve was fitted through the averaged points. The devi-ations of the fitted curve from a measured average value of pres-sure or impulse, was maintained at less than 10 percent.
Petes, J. , "Watch Your Equivalent Weight," Minutes of the 12thExplosives Safety Seminar, August 1970.
69
II Vj If the deviation was greater, that point was eliminated as being
an invalid measurement. Typically the error was of the order of
3 to 4 percent in pressure (because of the relatively steep slopeI60 to 70 deg of the pressure curve, an error in k is one-half the
error in P). It is thus believed that errors in % are much less
S I than 3 percent and hence errors in equivalency reported herein are
expected to be much less than 10 percent.
rI
II '
II
IIII
, 70
8. RESULTS OF TESTS ON SAND AS AN INERT SIMULANT
Calibration-type tests were carried out using sand as an Iinert simulant for Black Powder. The purpose of the inert simu-
lant tests was to determine the contribution of the booster ex-plosive to the airblast parameters. Initially it was believed 1that an adequate approximation to account for booster effects was
to subtract the pressure (or impulse) obtained in the tests on
sand from the values of pressure (or impulse) obtained on the Utests with Black Powder, using the same booster size. Although
it was recognized that blast wave addition is a nonlinear process,
it was thought that the effect of subtracting the booster-sand
pressures and impulses would be small. Although this is true, a
more correct method for accounting for the booster was derived;the iterative process described in Appendix B. Comparisons were
made in the equivalency values obtained by subtracting the sandtest booster effect and those equivalencies obtained by the more
accurate method of Appendix B. The difference in the results
were small, it was therefore decided that the more correct itera-
tive method should be used in this report and in all future work.
Therefore, in the final interpretation of the Black Powder dataI the sand test results are not used. The raw data on pressure !
and impulse for the series using sand can be found in Appendix A
j (Volume II).
7
I
m, II
Ik7
H - _ _.., .. ... ... .. .. .... .. ....... 4
UAS
lRE'lUAS, ANDSAL!
