JPyro – Articles

Display Fireworks And Stage Pyrotechnics In Use – Which Distances Are ‘Safe’ In Germany And Other Parts Of the EU?

Christian Lohrer

Abstract: Display fireworks and theatrical pyrotechnic articles are widely used in the EU by persons with specialist knowledge for local festivities, events, concerts and various music shows. According to the European Directive 2013/29/EU relating to the making available on the Union market of pyrotechnic articles, these articles are categorized as fireworks of category F4 and theatrical pyrotechnic articles of category T2, respectively. Before these pyrotechnic articles may be made available on the market, manufacturers must ensure that they satisfy the essential safety requirements (ESR) of this Directive. By application of the standard series EN 16261 for F4 articles and EN 16256 for T2 articles an assumption of conformity to the ESR is triggered. Both standards do not specify minimum safety distances to the spectators or to the audience, but give guidance to the Member States for setting up their own regulations for defining the safety distances by means of measured article-dependent performance parameters or construction properties. These safety distances differ between the Member States due to the cultural differences and various methods of calculation. This paper explains the procedures for defining safety distances for F4 and T2 in Germany. Respective advantages and disadvantages are pointed out, and results for identical items, categorized as F4 and T2, illustrate the current measures www.otcsildenafil.net. In addition, a brief overview of the corresponding regulations regarding display fireworks in some other European Member states is presented. The different approaches are compared with each other by calculating the respective safety distances for identical articles.


Ref: JPyro, Issue 33, 2014, pp39-51 (J33-39)


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Green Pyrotechnic Formulations Based on Metal-Free and Nitrogen-Rich Tetrazolylborate Salts

Thomas M. Klapötke, Magdalena Rusan and Jörg Stierstorfer

Abstract: The investigation of green-burning boron-based compounds as colorants in pyrotechnic formulations as an alternative for environmentally and health hazardous barium nitrate is reported here. Metal-free and nitrogen-rich dihydrobis(5-aminotetrazolyl)borate salts and dihydrobis(1,3,4-triazolyl)borate salts have been synthesized and characterized by NMR spectroscopy, elemental analysis, mass spectrometry and vibrational spectroscopy. The energetic and thermal properties have been determined as well. Crystal structures of compounds 5b, 7 and 13 were obtained. Pyrotechnic compositions have been prepared using selected dihydrobis(azolyl)borate salts as green colorants. In these compositions ammonium dinitramide and ammonium nitrate haven been used as oxidizers, and boron and magnesium as fuels. The burn time, dominant wavelength, spectral purity, luminous intensity and luminous efficiency as well as the thermal and energetic properties of these compositions were measured.


Ref: JPyro, Issue 33, 2014, pp24-38 (J33-24)


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Quantification of Visible Aerosols from Pyrotechnics: Metal and Metal Compound Additives

Rene Yo Abe, Yoshiaki Akutsu, Akihiro Shimada and Takehiro Matsunaga

Abstract: The effect of metal and metal compounds commonly used in pyrotechnics on visible aerosol development at high relative humidity has been investigated in combustion experiments using a combustion chamber. Ammonium perchlorate/ hydroxyl-terminated polybutadiene as oxidant/fuel system allowed aerosols generated from the additives to be observed in the absence of particles generated from the base composite. For magnesium and magnalium and all flame coloring agents except barium nitrate, light extinction measurements at 80% relative humidity were found to be proportional to the mass concentration of hygroscopic metal compound particles which are formed at high temperatures from metal chloride or metal vapors during combustion. Low visible aerosol development under humid conditions was observed for aluminium and titanium which have higher boiling points than magnesium and do not readily vaporize during combustion, as well as for barium nitrate which forms too small hygroscopic barium chloride particles and iron(iii) oxide which, because of its low boiling point, forms coarser iron(iii) chloride particles at lower temperatures.


Ref: JPyro, Issue 33, 2014, pp16-23 (J33-16)


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OPINIONS – Issues with UN explosives classification – a personal perspective

Dr Tom Smith

Abstract: The United Nations classification regime for explosives is well established and has undoubtedly led to improvements in transport safety. However there are challenges that the hazard based approach faces and this paper attempts to highlight some of the more pressing issues.


Ref: JPyro, Issue 33, 2014, pp9-15 (J33-9)

OPINIONS

This article is the first, we hope, of many written by experts in the Pyrotechnic and Explosives sectors to highlight issues of the day and to stimulate discussion both within the pages of the Journal and elsewhere.

Opinions are just that – they represent views by their respective authors which are not reporting of scientific findings, but nonetheless have a place in the pyrotechnic literature. Opinions will be peer reviewed, as are all articles in the Journal, and authors will, we hope, take account of comments from the Board and reviewers before publication. However the subjects discussed and the opinions expressed remain with the respective authors and may not reflect the positions of the Journal of Pyrotechnics, its Board or other contributors.

If you have a topic for consideration in future issues, please contact the Publisher directly.

OPINIONS will be free to download – but you do need to register on the site


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Screening of hexachlorobenzene (HCB) contents in fireworks

Silke Schwarz, Annett Knorr and Christian Lohrer

Abstract: This paper gives a brief overview of the findings of hexachlorobenzene (HCB) in fireworks compositions observed within EC type-examinations according to Module B (as set out in the annex II of the Directive 2007/23/EC) of the notified body BAM. In this work, roughly 220 samples were analysed, originating from 49 consumer fireworks articles of the category F2, such as batteries, combinations, fountains and rockets. It was found that the vast majority of samples showed concentrations below 5 mg HCB/kg. However, in three cases concentration values between 5 mg HCB/kg and 50 mg HCB/kg were observed, and in a further four cases extreme values of up to 8046 mg HCB/kg were detected www.tadalafilfromindia.net. The results of this study are compared with published HCB findings originating from market surveillance activities in Europe.


Ref: JPyro, Issue 33, 2014, pp3-8 (J33-3)


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Visual and Near Infrared Mass Extinction Coefficient of Five Pyrotechnic Screening Smokes

Matti Harkoma

Abstract: The screening properties of five different obscurants were compared at relative humidities of 30%, 50% and 85% and mass extinction coefficients were calculated. The obscurants were five military smokes: 1) a traditional hexachloroethane, Zn powder and TNT based screening smoke, the HC smoke as a reference, 2) a potassium chlorite, Mg powder and azodicarbonamide based screening smoke, the KM smoke, 3) a Mg powder based HC smoke, 4) a potassium chlorate, lactose and terephthalic acid based white coloured screening smoke, the TPA smoke, and 5) a titanium oxide based HC smoke. The apparatus was a CCD (Charge-Coupled Device) detector based dispersive spectrometer with a sample chamber and a humidity generator. The wavelength region was 450 to 850 nm. The important variable in determining how a military smoke retains its screening properties over time is the mass extinction coefficient. According to the results, the Zn based HC smoke has the best screening properties at low relative humidity. When the relative humidity is high the Mg based HC smoke has the best screening properties at first, but the KM type smoke retains its screening properties well, being the best of these three smokes after 20 seconds. After 60 seconds, the mass extinction coefficient of the KM smoke is 33% higher than the mass extinction coefficient of the reference smoke, when the mass extinction coefficient of the Mg based HC smoke is 20% lower than the mass extinction coefficient of the reference smoke.

Keywords: Screening smoke, obscurant, extinction coefficient, infrared


Ref: JPyro, Issue 32, 2013, pp67-77 (J32-67)


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Assessment of Explosives in Squibs

Lutz Kurth, Holger Krebs, Benjamin Theil, Olaf Mücke, Christian Lohrer

Abstract: Experiments in this study reveal that the initiating capability of commonly used squibs is not high enough to initiate PETN in all cases. The fulfilment of the ‘new’ essential safety requirement 4 as set out in the European directive 2013/29/EU and the categorization of squibs as theatrical pyrotechnic articles (T2) can therefore be justified, as the explosive investigated belongs to quite a sensitive type (initiation with low impulse energies possible). Underwater initiating capability tests according to EN 13763-15 led to meaningful results, showing that squibs are usually unable to initiate a secondary explosive. For a general assessment of the initiating capability of squibs and comparable (theatrical) pyrotechnic articles a threshold range of an equivalent initiation capability in grams of PETN on the basis of the performed underwater initiating capability tests was determined. It was found that squibs are generally not capable of  initiating secondary explosives if the underwater initiating capability test showed an equivalent initiation capability below 0.25 g PETN. As a consequence of this result, the underwater initiating capability test gives an effective and safer alternative to the experimental confirmation of the
‘new’ ESR 4 by direct contact of the article with the secondary explosive and should then be preferred to it.

Keywords: Squibs, ESR 4, PETN, underwater initiating capability, EN 13763-15


Ref: JPyro, Issue 32, 2013, pp57-66 (J32_57)


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The Senko Hanabi Sparkler: A Study Of Its Reaction Mechanisms

Frederick Van Der Sypt, M.D.

Abstract: The senko hanabi sparkler was found to be a very useful tool to study glitter phenomena. It was shown that current theoretical frameworks are incapable of explaining all observations. New elements were added to the discussion about the role of critical temperature and potassium sulfate concentration on the glitter flash. Also, the role of sodium bicarbonate as glitter enhancer and coloring agent was demonstrated in the senko hanabi sparkler.

Keywords: Senko hanabi, sparkler, satori effect, glitter


Ref: JPyro, Issue 32, 2013, pp43-56 (J32_43)


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The Senko Hanabi Sparkler: A Study Of Factors Affecting Construction And Performance

Frederick Van Der Sypt, M.D.

Abstract: This article describes the many variables that influence the proper functioning of a senko hanabi sparkler. Standardization of these variables led to the development of a reliable and optimized device. On top of this, two new effects were added to the traditional design, the first being a diversification and maximization of the spark effects by splitting the composition. The second innovation is the addition of pure magnesium that gives the sparkler a spectacular glitter finish. The possibility of producing a significantly colored glitter other than white and yellow, is brought into question by the current experiments.

Keywords: Senko hanabi, sparkler, satori effect, glitter


Ref: JPyro, Issue 32, 2013, pp27-42 (J32_27)


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Shellcalc© version 5.23

A new version of Shellcalc© is available (5.23)

The following changes have been made

  1. Taken out the backgrounds on the scaled plots to make copy/paste easier into Powerpoint (It comes in transparent now if you just select the Excel graph)
  2. Updated the copy/paste instructions
  3. Added a scaled plan plot
  4. Added a screengrab of superimposing Shellcalc© onto Google earth images
  5. Changed the algorithm for calculating long duration debris – this has increased the distances a bit, but is probably more accurate
  6. Changed the display of long burn fallout so it comes directly off the shell burst diameter at 4 points
  7. Updated the terrain category function
  8. Changed some of the term on the main screen to make it clearer

We have just run a course on getting the most from Shellcalc© – more details of upcoming courses at http://www.pyroworkshops.com

A few questions resulted from the Workshop:-

  1.  The plots on the main screen of shell bursts may be elliptical because Excel automatically scales the x/y axes on the plots on that screen. 
  2. Shellcalc© IS NOT a simulation tool – it is a tool for predicting shell trajectories and debris distances
  3. There are now 2 new graph screens where you can change the axes to maximise the information on the plot (as a normal Excel operation – right click and try) – specifically there to facilitate copy/paste and superposition on to images such as from Google Earth
  4. The “long burn” fallout and “normal debris” fallout plots are not meant to show exactly how the debris falls, but the distance to ground level is accurate

 


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