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The safety characteristics of flammable gases and liquids are required when identifying potentially explosive mixtures and taking appropriate actions concerning explosion protection. Examples are given in this review of the safe handling and evaluation of hazards during the processing, storage, transport, and disposal of flammable liquids and gases. The CHEMSAFE database is presented as a reliable source of safety characteristic data, and ist new open-access version is introduced. CHEMSAFE currently contains assessed properties for about 3000 flammable liquids, gases and mixtures. The lack of a broad experimental foundation in the extensive field of non-atmospheric conditions shows the need for further investigation and standardization. This review summarizes experimental evidence and estimation methods for safety characteristic data under non-atmospheric conditions pointing out current limitations. Suggestions for pre-normative research on safety data under nonatmospheric conditions are given.
Since the early drafting of the European standards for civil explosives, harmonised under directive 93/15/EEC and 2014/28/EU, blasting technology has developed notably. This is particularly evident for electronic detonators and electronic firing systems, and the EU commission agreed to initiate a standardisation initiative, also noting that the currently existing document on electronic detonators is “only” a Technical Specification (CEN/TS). This paper addresses the current activities in the area of standardisation. The EU is about to launch a formal standardisation request to cover the most recent technological developments not addressed by the current standards. The request would also include various adjustments of references to the new Directive for civil explosives, and in addition the task of developing a Technical Specification for on-site mixed explosives and corresponding manufacturing units. The latter has been included to address the nowadays frequently found mobile production on the basis of ammonium nitrate prills or emulsions.
Testing of hazardous materials and evaluating their hazardous properties concerning transport, handling or use is essential for the prevention of incidents. For this purpose, test methods have been developed and published that are used worldwide today (European Union, 2008, United Nations, 2019). For the evaluation of test results their correct measurement is of importance. On basis of the interlaboratory tests carried out by BAM and PTB within the framework of the CEQAT-DGHS in the last years, it is shown that there is a need for improvement in all the test methods examined so far. In addition to the interlaboratory tests further quality measures are mandatory (ISO, 2017). For example, methods for verifying the test equipment used in the laboratories should be developed.
The development of a verification method is demonstrated using the test method UN Test N.5 as an example. This test method is used to evaluate substances which in contact with water emit flammable gases. The basic principle of the verification method is demonstrated by Lüth et al. (2019). Requirements and difficulties during this development are discussed.
This test procedure UN Test N.5 has now been modified at BAM so that it is possible to measure very small or large amounts of both flammable and/or toxic gases over a long period of time in a validated and verified test apparatus, utilizing the principle of a gas collector. This allows us to determine slow as well as fast gas evolution rates. The determination of the evolution rates (e.g. total gas amount or flow rate) of toxic gases is of special interest because of the ongoing discussion how to evaluate and quantify toxic gases which are formed from a substance due to contact with water. Up today no validated test procedure for the measurement of evolution rates for toxic gases is described. It is shown that the newly modified test method could help to solve this problem.
The mixture of ammonium nitrate (AN) prills and fuel oil (FO), usually called ANFO, is extensively used in the mining industry as a bulk industrial explosive. One of the major performance predictors of ANFO mixtures is the fuel oil retention, which is itself governed by the porosity of the AN prills. Standardised tests routinely used to assess oil retention face several important limitations; the first being the difficulty to cover the wide range of porosity contents and morphologies from different types of ammonium nitrate prills; the second being the inability to evaluate the closed porosity, which is an important factor regarding the sensitivity of the explosive to detonation. In this study, we present how X-ray computed tomography (XCT), and the associated advanced data processing workflow, can be used to fully characterise the structure and morphology of AN prills. We show that structural parameters such as volume fraction of the different phases and morphological parameters such as specific surface area and shape factor can be reliably extracted from the XCT data, and that there is a good agreement with the measured oil retention values. XCT can therefore be employed to non-destructively and accurately evaluate and characterise porosity in ammonium nitrate prills.
Laboratory test results are of vital importance for correctly classifying and labelling chemicals as “hazardous” as defined in the UN Globally Harmonized System (GHS) / EC CLP Regulation or as “dangerous goods” as defined in the UN Recommendations on the Transport of Dangerous Goods. Interlaboratory tests play a decisive role in assessing the reliability of laboratory test results. Interlaboratory tests performed over the last 10 years have examined different laboratory test methods. After analysing the results of these interlaboratory tests, the following conclusions can be drawn:
1. There is a need for improvement and validation for all laboratory test methods examined.
2. To avoid any discrepancy concerning the classification and labelling of chemicals, the use of validated laboratory test methods should be state of the art, with the results accompanied by the measurement uncertainty and (if applicable) the probability of incorrect classification.
This paper addresses the probability of correct/incorrect classification (for example, as dangerous goods) on the basis of the measurement deviation obtained from interlaboratory tests performed by the Centre for quality assurance for testing of dangerous goods and hazardous substances (CEQAT-DGHS) to validate laboratory test methods. This paper outlines typical results (e.g. so-called “Shark profiles” – the probability of incorrect classification as a function of the true value estimated from interlaboratory test data) as well as general conclusions and steps to be taken to guarantee that laboratory test results are fit for purpose and of high quality.
The production of materials with dimensions in the nanometre range has continued to increase in recent years. In order to ensure safety when handling these products, the hazard potential of such innovative materials must be known. While several studies have already investigated the effects of explosions (such as maximum explosion pressure and maximum pressure rise) of powders with primary particles in the nanometre range, little is known about the ignition temperatures and flame velocities. Therefore, the minimum ignition temperature (MIT) of metallic nano powders (aluminium, iron, copper and zinc) was determined experimentally in a so called Godbert-Greenwald (GG) oven. Furthermore, the flame velocities were determined in a vertical tube. In order to better classify the test results, the tested samples were characterised in detail and the lower explosion limits of the tested dust samples were determined. Values for the burning velocity of aluminium nano powders are higher compared to values of micrometre powders (from literature). While MIT of nanometre aluminium powders is within the range of micrometre samples, MIT of zinc and copper nano powders is lower than values reported in literature for respective micrometre samples.