Lead block bulge

The lead block test is an empirical comparison test for assessing the explosive power of explosive substances. The measured variable is the lead block bulging after the explosion of a sample inside a lead block.

history

Lead block before and after the test (1 - sand, 2 - sample with detonator, 3 - lead block)

The test method was developed in 1885 by the chemist Isidor Trauzl , who as an Austrian officer and later with Alfred Nobel dealt with the investigation of explosives . The first international standardization was proposed in 1903. Later, in addition to the use of the cylindrical lead block, a spherical lead body was also proposed. Today's test, known as the BAM lead block test, is essentially based on the test conditions described in 1961 by the Federal Institute for Materials Research and Testing . Anhydrous picric acid was recommended as a reference substance for the test .

exam

Test arrangement

The test indicates how much the volume of a predefined cavity in a lead block with a diameter of 200 mm and a height of 200 mm increases when a defined amount of a test substance is ignited. For this purpose, 10 g of the test substance are dammed with quartz sand in a hole 125 mm deep and 25 mm in diameter and then detonated with a defined detonator. After the bore has been cleaned, the resulting volume is measured with water. The unit of measurement is cm ³ / g. Since a sample amount of 10 g is used in the test, the values in cm ³ for 10 g are often given in the literature .

As test F.3, the BAM lead block test is part of the test scheme for the classification of self-reactive substances of class 4.1 and organic peroxides of class 5.2 in the sense of the dangerous goods regulations . A modified lead block test F.4 is carried out with a lead block with a modified geometry. Further tests to assess the explosive power are the ballistic mortar tests F.1 and F.2.

Further comparison criteria are the TNT equivalent and the sand test .

Calculation methods

There are works that correlate measured lead block bulges ΔV _Trauzl with the _empiricalformula and material properties. When evaluating the lead block bulges of 70 substances of the type C _a H _b N _c O _d and including the molar mass M and the enthalpy of formation Δ _f H ⁰ for the gas phase, a function was found

{\ displaystyle \ qquad {\ text {(1)}} \ qquad \ Delta V_ {Trauzl} = c_ {0} + c_ {1} {\ frac {a} {M}} + c_ {2} {\ frac {c} {M}} + c_ {3} {\ frac {\ Delta _ {f} H ^ {\ circ}} {M}} \ qquad {\ text {mit}} \ qquad {\ begin {cases} c_ {0} = 1390 \\ c_ {1} = - 23881 \\ c_ {2} = - 26528 \\ c_ {3} = 114 {,} 18 ~ \ end {cases}}}

being found. A similar correlation resulted from an evaluation of the lead block bulges of 72 substances and 11 mixtures of the type C _a H _b N _c O _d based only on the sum formula and inclusion of correction factors V ⁺ and V ^- for different types of substitution that increase or decrease the values humiliate. The correlation found is:

{\ displaystyle \ qquad {\ text {(2)}} \ qquad \ Delta V_ {Trauzl} = c_ {0} + c_ {1} {\ frac {a} {d}} + c_ {2} {\ frac {b} {d}} + c_ {3} V ^ {+} + c_ {4} V ^ {-} \ qquad {\ text {with}} \ qquad {\ begin {cases} c_ {0} = 578 {,} 8 ~ \\ c_ {1} = - 175 {,} 4 ~ \\ c_ {2} = - 88 {,} 88 ~ \\ c_ {3} = 140 {,} 3 ~ \\ c_ { 4} = - 122 {,} 4 ~ \ end {cases}}}

The following table gives the correction factors for typical structural elements:

Correction factors
Structural element	V ⁺ (cm ³ )	V ⁺ (cm ³ )
R- (ONO ₂ ) _x , x = 1.2	1.0	-
R- (ONO ₂ ) _x , x> 2	0.5	-
R- (NNO ₂ ) _x , x = 1.2, ...	0.5	-
Ph- (NO ₂ ) _x , x = 1.2	0.5	-
H ₂ N-C (= O) -NH-R	-	1.0
Ph- (OH) _x or Ph- (ONH ₄ ) _x	-	0.5 x
Ph- (NH ₂ ) _x or Ph- (NHR) _x	-	0.4 x
Ph- (OR) _x	-	0.2 x
Ph- (COOH) _x or Ph- (ONH ₄ ) _x	-	0.9 x

Examples

Explosive power of chemical explosives and explosive mixtures based on their lead block bulge:

Lead block bulge (cm³ / g)
material	Measured value	Calculation according to equation (1)	Calculation according to equation (2)
Acetone peroxide	25th
Chlorate explosives	22-29
Hexogen (T4)	48
HMTD	33	37.1
Octogen (HMX)	48	44	47.2
Nitroglycerin	52	55.8	54.1
PETN / Nitropenta	52.3	51.4	51.7
Picric acid	31.5	34.1	32.9
TNT	30th	30th	30th
Dipicryloxide	37.3	36.2	39.0
Dipicrylamine	32.5	35.6	31.7
HNS	30.1	32.8	33.0

literature

UN Recommendations on the Transport of Dangerous Goods, Manual of Tests and Criteria. Fifth Revisited Edition 2009, United Nations Publication, New York / Geneva, ISBN 92-1-139087-7 .
Thomas M. Klapötke : Chemistry of High-Energy Materials. 3. Edition. Walter de Gruyter, Berlin / Boston 2015, ISBN 978-3-11-043932-8 , pp. 161–164.

Individual evidence

^ Proc. Intern. Congress Applied Chem. Berlin 1903, II 463.
^ WE Gordon, FE Reed, BA Lepper: Lead-Block Test for Explosives. In: Ind. Eng. Chem. 47, 1955, pp. 1794-1800, doi: 10.1021 / ie50549a028 .
↑ H. Koenen, KH Ide, Swart, KH in Explosivstoffe. 2, 1961, p. 36.
^ VJ Clancey: Assessment of explosion hazards of unstable substances. In: I. Chem. E. Symposiom Series. 33, 1972, pp. 50-55, (pdf)
↑ ^a ^b ^c Recommendations for the Transport of Dangerous Goods - Manual of Tests and Criteria, Fifth Revised Edition, ST / SG / AC.10 / 11 / Rev.5 , United Nations New York and Geneva, 2009, German translation 2015 by BAM , P. 298ff, (pdf) ( Memento of the original dated August 12, 2017 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / www.bam.de
↑ ^a ^b M. Kamalvand, M. Hossein-Keshavarz, M. Jafari: Prediction of the Strength of Energetic Materials Using the Condensed and Gas Phase Heats of Formation. In: Propellants Explos. Pyrotech. 40, 2015, pp. 551-557, doi: 10.1002 / prep.201400139 .
↑ ^a ^b M. Jafari, M. Kamalvand, M. Hossein-Keshavarz, S. Farrashi: Assessment of the Strength of Energetic Compounds Through the Trauzl Lead Block Expansions Using Their Molecular Structures. In: Z. Anorg. General Chem. 641, 2015, pp. 2446-2451, doi: 10.1002 / zaac.201500586 .
↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k J. Köhler, R. Meyer, A. Homburg: Explosivstoffe. 10th, completely revised edition. Wiley-VCH, 2008, ISBN 978-3-527-32009-7 .
↑ Entry on chlorate explosives. In: Römpp Online . Georg Thieme Verlag, accessed on January 3, 2015.

[1] Proc. Intern. Congress Applied Chem. Berlin 1903, II 463.

[2] WE Gordon, FE Reed, BA Lepper: Lead-Block Test for Explosives. In: Ind. Eng. Chem. 47, 1955, pp. 1794-1800, doi: 10.1021 / ie50549a028 .

[3] H. Koenen, KH Ide, Swart, KH in Explosivstoffe. 2, 1961, p. 36.

[4] VJ Clancey: Assessment of explosion hazards of unstable substances. In: I. Chem. E. Symposiom Series. 33, 1972, pp. 50-55, (pdf)

[orange_book-5] Recommendations for the Transport of Dangerous Goods - Manual of Tests and Criteria, Fifth Revised Edition, ST / SG / AC.10 / 11 / Rev.5 , United Nations New York and Geneva, 2009, German translation 2015 by BAM , P. 298ff, (pdf) ( Memento of the original dated August 12, 2017 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / www.bam.de

[Kamalvand-6] M. Kamalvand, M. Hossein-Keshavarz, M. Jafari: Prediction of the Strength of Energetic Materials Using the Condensed and Gas Phase Heats of Formation. In: Propellants Explos. Pyrotech. 40, 2015, pp. 551-557, doi: 10.1002 / prep.201400139 .

[Jafari-7] M. Jafari, M. Kamalvand, M. Hossein-Keshavarz, S. Farrashi: Assessment of the Strength of Energetic Compounds Through the Trauzl Lead Block Expansions Using Their Molecular Structures. In: Z. Anorg. General Chem. 641, 2015, pp. 2446-2451, doi: 10.1002 / zaac.201500586 .

[Köhler-8] ↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k J. Köhler, R. Meyer, A. Homburg: Explosivstoffe. 10th, completely revised edition. Wiley-VCH, 2008, ISBN 978-3-527-32009-7 .

[9] Entry on chlorate explosives. In: Römpp Online . Georg Thieme Verlag, accessed on January 3, 2015.