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The Klotz Group Contribution to Explosives Safety
Jaap Weerheijm; TNO Defence, Safety & Security; The Netherlands
Robert Conway; NAVFAC EXWC; USA
Abstract
The Klotz Group (KG) is an international group of experts on explosives safety that collaborate
based on two objectives: (i) to improve the knowledge base of explosion effects associated with
the storage, processing and transport of ammunition and explosives, and (ii) to develop engineering
data bases to quantify the explosion effects that enable consequence and safety assessments, and
also risk analyses.
The KG meets twice a year to identify and prioritize knowledge gaps and develop a road map to
bridge the gaps using KG funds, and leveraging each member country’s related national research
programs. The KG has been active for more than 30 years and at present its membership includes
explosives safety experts from eight countries: Germany, Norway, the Netherlands, Singapore,
Sweden, Switzerland, the United Kingdom, and the United States. The KG contribution to
munition safety changed over the years starting mainly from large and small scale experiments
dedicated to underground ammunition storage to nowadays a balanced approach of testing,
engineering tools and advanced computational analyses to quantify hazards from primary and
secondary debris, as well as airblast.
This paper presents a description of the KG aims and strategy, highlights of the KG contribution
to explosives safety over the years and its current endeavors.
Keywords: accidental explosion, ammunition safety, external safety, international collaboration,
experimental data, computational tools and guidelines.
Introduction
The Klotz Group (KG) has a long history and the establishment of its current form came about
quite gradually. Its origin goes back to 1966. A group of explosives safety personnel discussed the
potential solutions to reduce the blast effect caused by accidental explosions in underground
ammunition magazines. It was proposed to use a large closing device, a massive block (in German:
Klotz) creating a gigantic blast valve. Theoretical and experimental efforts were followed by a
successful “full scale” proof test in 1973. The four participants, Norway, Sweden, Switzerland and
West-Germany, decided to continue the fruitful cooperation within the field of explosives safety.
In November 1975 the Klotz Club was born. The terms of reference were clearly defined stating
the importance of data and knowledge exchange to achieve “a better utilization of resources”.
Three areas of mutual interest were identified:
- Explosives Quantity Distance data and prescriptions as applied to manufacture and storage
of ammunition;
- Structural response to both internal and external explosions
- Risk Analyses
