UN/CETDG/20/INF.21

COMMITTEE OF EXPERTS ON THE

TRANSPORT OF DANGEROUS GOODS

(Twentieth session,

Geneva, 7 – 16 December 1998,

agenda item 2(d))

Comments on ST/SG/AC.10/1998/45,

Transmitted by the Expert from the Netherlands

Introduction

In document ST/SG/AC.10/1998/45 the expert from France proposes to create a new entry in Chapter 3.2 for ammonium nitrate emulsions in Division 5.1. Those emulsions are frequently used as a precursor for blasting explosives. This allows 'on site mixing' and has obvious advantages, amongst others in transport since they can be excluded from Class 1.

In current practice they are shipped under various of different Classes. The emulsions are transported in considerable amounts globally, which would justify a separate entry for the ammonium nitrate emulsions. The expert from the Netherlands therefore supports creation of a new entry.

However, we believe the proposal from the expert from France is not complete. No criteria (except on the base of experience) are given on which to base the exclusion from. It is known that the properties of these emulsions can vary considerably, for instance depending on the size of the droplets, pH, chloride content and amount of NOx present. Classification purely based on the composition is therefore not possible.

Furthermore, the expert from France proposes that the competent authority will have to assign the applicable Packing Group (I, II or III). No guidance is given on what properties to base the assignment to a Packing Group.

Experts from the OECD-IGUS Working Groups on Energetic and Oxidising Substances (EOS) and Explosives, Propellants and Pyrotechnics (EPP) already have identified and discussed the mentioned problems and have decided to include it in their work programme for the next years. A joint session of the two Working Groups will be held in Stockholm in May 1999 to address the issue.

UN/CETDG/20/INF.21

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Proposal

Based on the above mentioned considerations, the expert from the Netherlands proposes to include the subject in the work programme for the next biennium of the Committee of Experts on the Transport of Dangerous Goods.

Based on research and/or discussion between experts proposals can then be drafted, for instance for tests and criteria for exclusion from Class 1 and for guidance for assignment of the Packing Group.

The document ST/SG/AC.10/1998/45 should consequently kept for further consideration during the next biennium as a base for discussion.

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