Experts’ Report on Use of the Water Abrasive Suspension Jet (WASJ) – Technique for Cutting Explosives

1. Procedure

In the document of 25th September 2001 the company Applied New Technologies AG (ANT AG) contracted the Bundesanstalt für Materialforschung und -prüfung (BAM) (Federal German Institute for Materials Research and Testing (FIM)) to conduct a safety appraisal of the WASJ technique. The following documentation accompanied the request:

	DIN EN ISO 9001 certificate of 27th February 2001 for the company ANT AG,
	EC conformance declaration as defined in EC-RL 98/37/EG, EC-RL 89/336/EEC and EC-RL 73/23/EEC for the mobile AZE-700-12 of 8th March 2001.
	ANT AG company prospectus– “Cutting with water”,
	ANT AG company presentation,
	Short description of the WASJ technique,
	Literature survey with copies of individual sources (7 in total), and
	Investigation report on the cutting of rocket motors and munitions using the WASJ technique, June to December 1994 in Pinnow.

An experts’ report on abrasive water jet techniques has already been produced by the BAM dated 21st August 1992, Journal No. 4-3861/92, on behalf of the company ALBA-lndustrie und Umweltschutz GmbH. The current experts’ report brings the 1992 report up to date and covers the latter completely in terms of content.

2. Description of the WASJ technique

The WASJ technique can be used for, amongst other applications, the severing of sensitive components and objects such as, e.g. munitions. The functional principle is that high-pressure water, usually with the addition of an abrasive medium, impinges at very high velocity on to the component/object that is to be dismantled.

The parameters used for the technique at the present time are:

	Working pressure of 50 MPa to 200 MPa,
	Water consumption rate of 4 l/min to 240 l/min,
	Abrasive material consumption rate (primarily garnet sand) of 0.1 kg/min to 15 kg/min, and
	a nozzle diameter from 0.3 mm to 3 mm.

The dismantling activities can be performed in air, under water and in special environments.

It is possible to operate the cutting nozzle using a cutting table or a manipulator from a distance of more than 500 m.

It is also possible to collect and treat the cutting water.

3. Evaluation fundamentals and criteria

The WASJ technique, which according to information from ANT AG can be used universally, in this report is evaluated exclusively with regard to its suitability for the dismantling of explosives and objects containing explosive.

As regards safety the dismantling of explosives and of objects containing explosive in explosives industry companies is subject to the German Berufsgenossenschaften association regulations for health and safety protection (regulations for the dismantling or disposal of explosives) BGR 114, up to March 2001 designated as ZH 1/47.

For the case where the WASJ technique is used for stationary dismantling activities in air, the following technique-specific requirements must be observed:

	In accordance with Item 5.23 of BGR 114 working processes in which the explosives are likely to be subjected to extraordinary conditions, must be performed “with safety”. The high pressure water cutting technique is counted amongst these working processes. For “with safety” working processes those workers that are immediately concerned with operation of the technique are also to be protected from the effects of any fires or explosions that may occur.
	A further technique-specific requirement is provided by Item 5.15 of BGR 114, which states that no moisture-sensitive explosives (in particular metal powder mixtures that can self ignite with the appearance of moisture, or can form flammable or poisonous gases) may be dismantled.
	The cutting water that accumulates as a result of use of the technique is contaminated with explosive. In accordance with § 70 of BGV B5 (up to March 2001 designated as UW VBG 55a) undissolved explosives are to be separated from the waste water and disposed of. As a result use of the WASJ technique in company operations is only permitted in conjunction with a facility for treatment of the cutting water.
	The waste products containing explosive are to be collected in special containers under the terms of § 69 of BGV B5 and are to be destroyed on the operation’s combustion site or in accordance with special instructions.

In accordance with Item 15.1 of Attachment 5 of BGR 114, BGV C23 (up to March 2001 designated as UW VBG 39) and BGV C24 (up to March 2001 designated as UW VBG 46) are to be observed when using the technique for mobile dismantling tasks under water, e.g. in the context of ordnance removal. The safety regulations do not contain any explicit requirements that are specific to the WASJ technique.

There are no requirements that are specific to the WASJ technique that apply if the technique is to be used in other kinds of applications, or under other conditions.

In addition to the cited requirements that are specific to the WASJ technique the general safety requirements of BGV B5 must be observed in operation of the WASJ facility. The facility must also satisfy further requirements that stem from other areas of legislation, such as health and work protection, environmental protection and equipment and machine safety. Examinations in these respects are not performed in this report.

4. Safety evaluation of the technique

The WASJ technique is basically suitable for the dismantling of explosives and objects containing explosive in air, under water and in special environments from the safety viewpoint, as the accompanying literature sources show. A necessary prerequisite for any application is that the option of remote operation of the technique is utilised. This explicitly fulfils the safety requirement that the technique is used in air “with safety”, and fulfils the spirit of the requirement when the technique is used under water or in special environments.

For the case of stationary use of the WASJ facility in air, there is a practical set of safety regulations that must be observed. This set includes, amongst others:

	criteria for establishing the risk group of the materials and objects to be dismantled (in BGV B5).
	safety distances to be maintained between the location of the materials and objects to be dismantled, and the personnel operating the WASJ facility and other items in the operational environment (in BGV B5).
	protective distances to be maintained between the location of the materials and objects to be dismantled, and the items that deserve protection in the vicinity (BGR 114),
	requirement on the configuration of protective structures (in BGV B5).

The requirements of BGV B5 and BGR 114 can logically be translated across to non-stationary use of the WASJ facility in air.

For use of the technique under water and in special environments there is no practical set of safety regulations available. In such cases a separate safety evaluation must be performed.

A further necessary prerequisite for stationary operation of the WSS facility in air is the collection and treatment of the cutting water contaminated with explosive. The execution of the cutting water treatment must meet the safety requirements of BGV B5 and must be accounted for separately. Furthermore the disposal route for the residues contaminated with explosive must be demonstrated for each type of application.

5. Summary

As regards safety the water abrasive suspension jets (WASJ) technique is basically suitable for the dismantling of explosives and objects containing explosive in the media of air and water and in special environments. The technical prerequisites are presented with the technique that enable dismantling to be performed “with safety”.

For dismantling tasks in air a practical set of safety regulations in BGV B5 and BGR 114 must be observed.

For dismantling tasks under water and in special environments the general protection requirements must be made specific for the technique in the context of examinations of individual cases, and their maintenance must be recorded.

Bertin, 3rd December 2001

Dr. Barfuss

Senior Scientific Officer

Head of Laboratory

“Explosives and propellants”

Dr.-Ing. Otto

Work Unit II.302

“Safety of explosives facilities”

(Official stamp)