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This paper aims at giving an overview about this entire standardization process, explaining the main differences of the EN versions from 2015 and 2022, outlining the practical implications for the stakeholders applying these ENs and giving a cautious look into the future requirements for fireworks in Europe.
This presentation aims at giving an overview about this entire standardization process, explaining the main differences of the EN versions from 2015 and 2022, outlining the practical implications for the stakeholders applying these ENs and giving a cautious look into the future requirements for fireworks in Europe.
Propane/air deflagrations and CTA measurements of turbulence inducing elements in closed pipes
(2008)
The current paper presents experimental investigations on several influence parameters of deflagrations in long closed pipes. The experiments were carried out with different propane/air mixtures, various length-to-diameter ratios (up to L/D=143, D=0.159 m) and miscellaneous initial pressures. Maximum values of explosion pressures and flame speeds were found at stoichiometric propane/air compositions. With increasing L/D, the explosion pressures decreased while higher flame speeds were determined. In addition, elevated initial pressures led to rising explosion pressures. Furthermore, it is well known that turbulence inducing elements in pipes, ducts or vessels enhance the heat and mass transfer during reactive flows. This may lead to a significant acceleration of ongoing gaseous reactions and could finally cause a deflagration to detonation transition (DDT) aligned with much higher pressures and flame speeds. Therefore, constant temperature anemometry (CTA) measurements were carried out to describe the influence of frequently used flange assemblies and baffles on the velocity and turbulence distributions of air flows in steel pipes similar to those in the explosion measurements. The experiments showed that in contrast to flange assemblies, baffles caused a significant increase of the turbulence intensity in pipe flows.
There is a wide variety of approaches across the world in determining appropriate “safety distances” for firework displays. Comparison of the different national approaches and distances for Shells derived from Shellcalc© highlights the variety and derivation of the “safety distances” adopted and these distances are related to the various failure modes of Shells that may affect the audience. In particular the effects of angled mortars and wind are compared and considered. It is not intended that this paper should encourage the maximum distances derived always to be adopted, but that an appreciation of the probabilities and hazards of various accident scenarios and therefore the risks involved be part of the decision making process for designers and commissioners of displays as well as enforcing authorities.
The European Standard series EN 16261 consisting of four parts deals with the testing and assessment of display fireworks in order to satisfy the essential safety requirements of the Directive 2007/23/EC which have to be met before placing these articles on the EU market. The current Version of this Standard provides mortar dimension limits to be used for the assessment of burst heights of spherical Shells, but lacks corresponding provisions for cylindrical shells. The aim of this study was threefold:
1. To check whether the requirements for spherical shells would overlap with the ones
for cylindrical shells,
2. To compare several test procedures for height measurements with each other to
minimize the measurement uncertainty of the effect dimensions, and
3. To evaluate drift distances in order to check whether the current national provisions
on safety distances for Professional fireworks displays need adaption during the
implementation of the new European directive 2013/29/EU on pyrotechnics in German legislation.
For this study, a large number of cylindrical shells was specifically manufactured to guarantee lull control on all relevant constructional aspects. These shells were designed with a smoke tracer and no burst Charge so that they would fall back to the ground in order to investigate their drift distances. Their gross mass corresponded to commercially available display shells, though, consisting of defined inert substances inside the shell. The following Parameters were varied in this study: caliber (75 mm, 100 mm, 150 mm), shell length per caliber (single and double length), lift Charge (hard and soft burst effect), mortar length per caliber (short and long). In total, more than 120 shells were manufactured and tested. Results show a good application of the proposed test procedures regarding the mortar dimensions given in the Standard series for cylindrical shells as well. The following test procedures were part of this study: Radar Doppler System, video grammetric System, universal surveying instruments, and mortar internal pressure measurements. Observed drift distances in relation to the caliber and effect heights are discussed and assessed.
Pyrotechnic smoke generators fall under the Directive 2013/29/EU in Europe and could potentially belong to all categories except consumer fireworks. These types are especially present in the field of “Other Pyrotechnic Articles” of the categories P1 and P2, e.g. as simulation devices for paintball or airsoft gaming. The specific users of these products are aware of the corresponding smoke liberation during use and usually wear protective equipment to minimize exposure to potentially harmful aerosols. However, such products are often misused against the labelling requirements in locations where these articles are not supposed to be used, like football stadiums and demonstrations. In contrast to the intended use, uninvolved third parties are likely exposed to these reaction products without proper protective equipment. This study aims at identifying the transient particle size range of the aerosols emitted during the functioning of such common smoke generators for simulation purposes. In total four different types of articles were investigated, with five colors per type (white, blue, green, red, orange). Results show that the majority of the particles were emitted in a range between 40 nm and 350 nm, with some variation depending on the smoke color. Particles with diameters of less than 100 nm are generally of specific concern, as they can penetrate the alveolar system of the human lungs and therefore present a specific hazard.
