ASTM D2541-93(2001)
(Test Method)Standard Test Method for Critical Diameter and Detonation Velocity of Liquid Monopropellants (Withdrawn 2003)
Standard Test Method for Critical Diameter and Detonation Velocity of Liquid Monopropellants (Withdrawn 2003)
SCOPE
1.1 This test method covers the evaluation of two properties of a high-energy liquid propellant. In one form, the critical internal diameter is determined in a given type of metal or plastic tubing below which propagation of stable high-velocity detonation will not take place. In the alternative form, which uses more material, detonation rate is concurrently measured. The composite donor of either size may be used in most instances to initiate detonation in experimental trap designs.
1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
General Information
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Standards Content (Sample)
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Designation: D 2541 – 93 (Reapproved 2001)
Standard Test Method for
Critical Diameter and Detonation Velocity of Liquid
Monopropellants
This standard is issued under the fixed designation D 2541; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope vital parameter in establishing the critical diameter is that of
confinement of the test specimen. The fact that detonation
1.1 This test method covers the evaluation of two proper-
occurs or does not occur in Type 347 stainless steel tube does
ties of a high-energy liquid propellant. In one form, the critical
not necessarily imply that the same results would be obtained
internal diameter is determined in a given type of metal or
in an aluminum, copper, glass, etc., tube of similar dimensions.
plastic tubing below which propagation of stable high-velocity
Type 347 stainless steel tube is acceptable for a standard
detonation will not take place. In the alternative form, which
reference test, but for practical application, diameters should be
uses more material, detonation rate is concurrently measured.
studied in the materials and wall thicknesses proposed for use.
The composite donor of either size may be used in most
4.2 When working with high-energy liquid propellants,
instances to initiate detonation in experimental trap designs.
serious consideration shall be given to the possibility that a
1.2 This standard does not purport to address all of the
detonation originating in the engine can propagate upstream to
safety concerns, if any, associated with its use. It is the
the propellant tank and cause a disastrous explosion. Therefore,
responsibility of the user of this standard to establish appro-
it is useful to know the minimum diameter of propellant line
priate safety and health practices and determine the applica-
through which a detonation of the propellant in question can
bility of regulatory limitations prior to use.
propagate. If it is impracticable to use propellant lines smaller
1.3 The values stated in SI units are to be regarded as the
than this minimum, it will be necessary to design and test
standard. The values given in parentheses are for information
detonation traps in larger lines. The minimum or critical
only.
diameter (often referred to as “failure” diameter), when the
2. Terminology conditions are properly defined, can be a useful measure of the
shock sensitivity of similar systems. The detonation velocity of
2.1 Definition:
the propellant in question is another property of interest.
2.1.1 critical diameter—the largest diameter that will not
4.3 The three determinations, namely: minimum diameter
detonate when the donor is exploded.
for propagation, detonation trap requirements, and detonation
3. Summary of Test Method
velocity, have much in common; all presuppose the initiation
of a stable detonation in a liquid contained in a tube. The key
3.1 Various diameters of tubing are filled with propellant,
to the present test method is the use of a donor stage consisting
and an attempt is made to cause the propellant to detonate by
of the material under test. Although a compound initiator
use of a secondary detonating medium (the donor).
comprised of a blasting cap and high-explosive booster is
4. Significance and Use
employed, the true donor is a length of the subject material
sufficient to assure establishment of a stable detonation char-
4.1 It should be emphasized that the critical diameter, as
acteristic of the test medium ahead of the first test section or
determined under these conditions, is valid only for these
measuring station. Questions of wall and boundary discontinu-
conditions and is not an intrinsic property of the sample. One
ity are thereby eliminated along with the accompanying
complications of impedance mismatch and perturbation of the
This test method is under the jurisdiction of ASTM Committee F07 on
shock front.
Aerospace and Aircraft and is the direct responsibility of Subcommittee F07.90 on
Executive.
5. Apparatus
Current edition approved March 15, 1993. Published May 1993. Orginally
published as D 2541 – 66 T. Last previous edition D 2541 – 83. 5.1 The liquid under test, depending on what measurement
This test method is identical in substance with the JANNAF method, “Critical
or measurements are to be made, shall be contained in one of
Diameter and Detonation Velocity Test,” Test Number 8, Liquid Propellant Test
the following three assembled units:
Methods, May 1964, published by the Chemical Propulsion Information Agency,
Johns Hopkins University, Applied Physics Laboratory, Johns Hopkins Rd., Laurel,
MD 20707.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 2541 – 93 (2001)
5.1.1 Assembly No. 1, Critical Diameter Measurement (Fig. 5.1.2.1 Section D or “test” section, Fig. 1 (b), shall consist
1 (a)): of Type 347 stainless steel tubing (1-in. (25.4-mm) outside
5.1.1.1 Section A, Fig. 1 (a), shall consist of Type 347 diameter by 0.049-in. (1.24-mm) wall thickness by 11-in.
stainless steel tubing (1-in. (254-mm) outside diameter by (279-mm) length). Two timing stations of either ionization
0.049-in. (1.24-mm) wall thickness by 6-in. (152-mm) length). wires or T-1 targets (Note 1), 100 mm apart, and located at
When filled with test sample, it is considered the “self donor” approximately 5 and 9-in. (127 and 229-mm) levels from the
section. booster end, shall be used for the rate measurements. The
5.1.1.2 Section C, Fig. 1 (a), shall consist of Type 347 probes inserted in the container can be sealed with epoxy
stainless steel tubing (30-in. (762-mm) length) of any one of cement or passed through neoprene sleeves, provided either is
the following sizes: compatible with the test liquid.
(a) T-1 targets are pressure-shorting switches encased in a
Outside Diameter, Wall Thickness,
in. (mm) in. (mm) 1
copper tube ⁄4 in. (6.4 mm) in diameter by 1 in. (25.4 mm)
1 (25.4) 0.049 (1.24)
long. These switches are inserted through holes in the side of
⁄4 (19.0) 0.049 (1.24)
⁄8 (15.9) 0.035 (0.89) the container. (The same item in an aluminum case bears the
⁄2 (12.7) 0.035 (0.89)
designation T-2 target.)
⁄8 (9.5) 0.035 (0.89)
5.1.2.2 The downstream end of Section D is closed by
⁄4 (6.4) 0.035 (0.89)
⁄8 (3.2) 0.020 (0.51)
crimping or plugging.
5.1.2.3 A longer container and more distance between
When filled it is considered the “test” section.
stations, or a greater number of stations is required if greater
5.1.1.3 Section A and Section C is connected by means of a
accuracy in rate measurement is required.
stopper of rubber or other suitable material compatible with the
5.1.2.4 If the test sample is limited, smaller diameters can be
propellant under test. The top of Section C is flush with the top
used.
of the stopper.
5.1.3 Assembly No. 3, Combination Critical Diameter and
5.1.1.4 The downstream end of Section C is closed by
Detonation Velocity Measurement (Fig. 1(c)):
crimping, plugging, or clamping, the latter being shown in Fig.
5.1.3.1 Section B, or “self donor” section, Fig. 1(c) (see
1(a) and (c). A pinch clamp over vinyl tubing shall be used in
5.1.2.1).
freeing the container, especially one of small diameter, of
5.1.3.2 Section C, or “test” section, Fig. 1(c) (see 5.1.1.2).
entrapped air during the filling operation.
5.1.2 Assembly No. 2, Detonation Velocity Measurement 5.1.3.3 Section C, connection to Section B (see 5.1.1.3).
(Fig. 1 (b)): 5.1.3.4 Section C, closure at bottom (see 5.1.1.4).
FIG. 1 Diagram of Apparatus
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
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D 2541 – 93 (2001)
5.1.3.5 Additional timing stations can be positioned along frequently. Working garments shall be free from dust-
the length of Section C if rates are desired in small-diameter collecting features such as trouser-cuffs, and laundered fre-
tubes. quently.)
5.1.3.6 The apparatus as described is suitable for determin-
5.1.6 Detonator—Detonation in the booster pellet shall be
ing critical diameters up to 1 in. (25.4 mm) (the donor itself initiated by an electric blasting cap which fits snugly into the
acts as the 1-in. section), but if the minimum diameter for hole in the booster. The cap used with the pentolite booster
propagation is greater than 1 in., a larger donor shall be used. shall be a No. 8 commercial cap. (Warning—Electric blasting
This donor should be 1 ⁄2 or 2 in. (38.1 or 50.8 mm) in
caps contain primary explosives, which are easily initiated by
diameter, as necessary, but otherwise of the same length and
relatively mild physical shock. Consequently, every precaution
wall thickness (0.049 in.) (1.24 mm) as the standard donor. The
shall be taken by those who work with them, with particular
diameter of the high-explosive booster and detonator holder
emphasis on gentle handling and protection from electrostatic
shall be scaled up to match, and the constant L/D of 2 shall be
charges. Accumulation of static charges by personnel shall be
maintained. For instance, if the donor is 2 in. in diameter, the
prevented by use of all-cotton clothing and special conductive
booster will be at least 2 in. in diameter by 4 in. (102 mm) long.
shoes.)
5.1.4 Assembly No. 4, Trap Testing—In testing detonation
5.1.7 Rate-Measurement Apparatus—A 10-MHz counter, or
traps, the trap to be tested is attached to either Assembly No. 1
an oscilloscope (with suitable camera attachment) with a
or 3 in place of the small-size tubing being tested for critical
5-μs/cm sweep frequency, can be used to measure the time of
diameter (Section C). Certain configurations can require filling
propagation between the stations (Note 1). The oscilloscope
with liquid before assembly with the donor section. In this
has an advantage in that the trace can give some evidence as to
event, the precautions under Section 6 shall be observed.
the cause of malfunctions when they occur.
5.1.5 Booster—The booster charge shall consist of a cylin-
NOTE 1—It can be desirable to use more than two stations or probes,
drical pentolite pellet (or equivalent high oxidizers), nominally
thus obtaining replicate rate measurements. A circuit diagram for single-
2 ⁄2 in. (64 mm) long by 1 in. (25.4 mm) in diameter, weighing
oscilloscope rate measurements is given in Fig. 2.
51 6 0.3 g with a density of 1.65 6 0.01 g/cm , and containing
1 1
5.1.7.1 Time-Interval or Counter-Chronograph
an axial cavity ⁄4 in. (6.4 mm) in diameter by ⁄2 in. (12.7 mm)
Apparatus—The instrument shall be a 10-MHz counter-
deep for insertion of the electric detonator. (Warning—
chronograph (0.1 μs time base) with a resolution of 0.1 μs in
Pentolite is not considered to be a particularly sensitive
explosive, but handle with due respect. Careless or rough the range from 0.3 μs to 1 s. The unit shall have an input
handling can be fatal. Remembered, too, that practically all sensitivity of 0.2 V rms. The input impedance shall be 1 MV,
high explosives are quite toxic. Handle them with particular direct or a-c coupled, trigger slopes either positive or negative.
Step attenuators shall provide trigger voltage adjustment hav-
care to avoid spreading the material by contact of the hands
with other parts of the body. Wash hands with soap and water ing a range of 61, 610, and 6100 V.
All resistors 6 10 percent, 1 W
R —2000 V
R —50 V
R —1 MV
C —3000 pf, 610 percent, 600 V, dc (C may be changed to lengthen or shorten the pulse width)
1 1
C —0.05μ F, 620 percent, 600 V, dc
D—1N34 crystal diode
B—battery 25 to 50 V, dc
S —trigger station
S ,S ,S ,S —rate-measuring stations
1 2 3 4
FIG. 2 Four Channel Mixer Circuit Producing Four Positive Pulses
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 2541 – 93 (2001)
5.1.7.2 Counter-Chronograph Input Circuitry—Counter-
chronographs currently in use require input voltage pulses with
relatively fast rise times and moderate amplitudes. Both of
these conditions can be met with the simple R-C circuit
described in two forms in Figs. 3 and 4. Since most counter-
chronographs permit polarity and slope selection of the trig-
gering pulses, it is convenient and frequently desirable to
provide maximum pulse isolation by using opposite polarities
FIG. 4 Practical 2-Channel R-C Pulse-Forming Circuit
Producing a Positive Pulse in One Channel and a Negative Pulse
for “start” and “stop” triggering pulses from adjacent probes.
in the Other Channel
The circuits shown schematically in Figs. 3 and 4 were
designed to provide output pulses of opposite polarity when the
inputs are “shorted” through ionization probes or T-1 targets.
through (7)) amply cover this subject. State and local regula-
With the supply voltage polarities as shown, the output pulse at
tions concerning transportation, storage, and use of explosives
J is negative when J is shorted, while the output pulse at J is
3 1 4
should be consulted and followed.
positive when J is shorted.
2 6.2 Before each shot, the firing circuit shall be tested for
5.1.7.3 Oscillograph Circuitry—The circuit for the oscillo-
continuity with a blasting galvanometer. The shot can be
graph is shown in Fig. 5 and the circuit for the power supply is
conveniently fired from the remote control point by means of
shown in Fig. 6. With this apparatus, it is necessary to
a portable blasting machine. The firing line shall consist of
synchronize the circuit, and for this a twisted wire (No. 32 B &
16-gage (1.29-mm) or heavier duplex copper conductor cable.
S gage (0.202-mm) enameled copper wire is satisfactory) shall
6.3 It is recommended that the firing line and all instrument
be inserted between the pentolite donor and the acceptor.
lines have a positive disconnect at the firing position. The
5.1.8 Firing Chamber—It is necessary to provide protection
safest practice is to provide an ungrounded shunt block for
from high-velocity fragments and some means of recovering
each of the lines, best located in a box with a hinged cover and
the remains, if any, of the acceptor tube. In some instances it is
equipped with a lock. Routine
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