Original Communication
Are full or empty beer bottles sturdier and does their fracture-threshold suffice to break the human skull?

https://doi.org/10.1016/j.jflm.2008.07.013Get rights and content

Abstract

Beer bottles are often used in physical disputes. If the bottles break, they may give rise to sharp trauma. However, if the bottles remain intact, they may cause blunt injuries. In order to investigate whether full or empty standard half-litre beer bottles are sturdier and if the necessary breaking energy surpasses the minimum fracture-threshold of the human skull, we tested the fracture properties of such beer bottles in a drop-tower.

Full bottles broke at 30 J impact energy, empty bottles at 40 J. These breaking energies surpass the minimum fracture-threshold of the human neurocranium. Beer bottles may therefore fracture the human skull and therefore serve as dangerous instruments in a physical dispute.

Introduction

The examination of living or deceased victims of bar fights is not uncommon in routine forensic practice. These fights are commonly carried out with fists, feet, furniture, and drinking vessels.

Depending on the state of the drinking vessels, namely intact or broken, different trauma forms are to be expected. According to a British group,1 readily available one pint beer glasses such as straight-sided glasses, referred to as nonik, and tankards display a mean impact resistance of up to 1.7 Joule (J). The glass shards of shattered beer glasses may give rise to stab and cut wounds, which may sever blood vessels or other vital structures of the body. Indeed, glasses with lower impact resistance cause more injuries,2 for which reason toughened glassware has been advocated.

On the other hand, if the drinking vessels remain intact, they may serve as clubs. In Switzerland and various other countries, refillable (and therefore sturdy) beer bottles are commonly encountered in pubs and at festivals. In Switzerland, the half-litre, refillable beer bottle is, according to the authors’ own experience, a commonly utilized instrument in physical disputes.

The authors have been asked at court whether hitting a human on the head with such intact bottles suffices to break a skull and whether full or empty bottles are more likely to cause such injuries. Obviously, this depends on the breaking properties of the bottle. If the bottle (full or empty) breaks at a minimal energy, no skull fracture is to be expected. On the other hand, should the stability of the bottle surpass that of the head, severe, even life-threatening injuries may be inflicted.

We therefore tested the breaking energy of such beer bottles in a drop-tower as described below in order to estimate at which energies the bottles break and if this amount of energy exceeds the energy necessary to inflict serious injuries to a victim.

Section snippets

Methods and materials

Ten (six empty and four full) standard 0.5 l beer bottles (Feldschlösschen Brewery, Rheinfelden, Switzerland, Fig. 1) were examined. The full bottles weighed 898 g, the empty ones 391 g. With multislice computed tomography (Somatom Emotion 6, Siemens Medical Solutions, D-91301 Forchheim, Germany) the wall thickness was measured. The minimal thickness was 0.2 cm and maximal thickness 0.36 cm (Fig. 2).

To one side of the beer bottles, a 7.5 × 1.2 × 5 cm pinewood board was fixed using a thin layer of

Results

The full beer bottles tolerated energies of up to 25 J (N = 2), but burst at 30 J (N = 2), whereas the empty beer bottles shattered at energies of 40 J (N = 4) but not below this threshold (N = 2). Thus, the empty beer bottles withstood about 10 J more than the full beer bottles before breaking.

Discussion

Although the sample size in our experiment is very small, and therefore eludes statistical analysis, a certain trend is clearly deducible, namely that full beer bottles tend to break at considerably lesser energies.

The full beer bottles broke at 30 J, whereas the empty bottles shattered at 10 J more, namely at 40 J. As shown in this experiment, the standard 0.5 l beer bottles are undoubtedly – regardless of whether they are full or empty – more suitable clubs than common beer glasses1 which break

Conclusions

Empty beer bottles are sturdier than full ones. However, both full and empty bottles are theoretically capable of fracturing the human neurocranium. We therefore conclude that half-litre beer bottles may indeed present formidable weapons in a physical dispute. Prohibition of these bottles is therefore justified in situations which involve risk of human conflicts.

However, further studies involving different bottle types and an examination regarding the extent of brain damage is needed to assess

Conflict of interest statement

There are no conflicts of interest.

Acknowledgements

The authors wish to thank the Science and Technology Division, Armasuisse, Ministry of Defence, Switzerland, for assistance in conducting the experiments and to Renate and Werner Bolliger, PhD, for help in language editing and manuscript preparation.

References (3)

  • J.P. Shepherd et al.

    Impact resistance of bar glasses

    J Trauma

    (1993)
There are more references available in the full text version of this article.

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