Protection for cash dispensers from being blown-up by explosive gas mixtures

The number of attacks on cash dispensers in banks has considerably increased during the last few years. The perpetrators usually use explosive gas mixtures, which are locally produced from individual high-risk gases and channelled into the safe. Gas explosions in the cash dispenser safe are difficult to control and exhibit a large destructive potential.

Ruined or burned-out bank offices, destroyed cash dispensers and looted cash are the usual results. Perpetrators sometimes suffer serious injuries as well because they have underestimated the strength of the explosion or the explosive mix ignites too early.

In order to equip cash dispensers against such attacks, the Federal Institute for Materials Research and Testing (BAM), commissioned by the VdS, has carried out a series of systematic explosion tests on different types of cash dispensers at BAM's open-air test facility in Horstwalde (Brandenburg).

This facility – which is unique in the Federal Republic of Germany – enables explosion tests using volatile gases the same as those used in the past by the criminals. The cash dispensers were equipped with pressure and temperature sensors to measure the impact of the explosions on the material of the safe. High-speed video photography enabled an exact analysis of material failure.

In order to prevent cash dispensers from being blown up in the future, preventive measures such as amended design of the safe or the use of gas sensor alarms can be prepared.

BAM and VdS intend to co-operate in this special field of public safety in the interest of avoiding future damage to property and people. In addition to further practical investigation, design modifications relating to the specific risks should be discussed with all manufacturers of high-value containers.

The first VdS-recognized safety measures are expected shortly: a dye system, which indelibly marks the notes and makes them very difficult or even impossible to use. VdS presented a test agreement which describes the specifications of design improvements required for high-value containers to resist gas attacks at the annual burglary-theft conference on 30 and 31 May 2007.

Contact:
Dr. rer. nat. Volkmar Schröder
BAM Division II.1 Gases, Gas Plants
Phone: +49 30 8104-3440, fax: +49 30 8104-1217
Email: volkmar.schroeder@bam.de