The Column Model – Physico-Chemical Effects (Part 5)

Explosion against a black background

© aleksandar nakovski -

The column model of TRGS 600 [1] as an assistance for the substitution check is already explained in several blog posts. I already introduced the columns dealing with health and environmental hazards. We now switch to hazardous substances that represent a hazard due to their physico-chemical effects.

Physico-chemical effects (column 4)

Column 4 of the column model deals with the physical-chemical hazards posed by the substances. If the substance is explosive, flammable or corrosive to metals, for example, it is classified accordingly in the categories of the column model from “Very high hazard” to “Negligible hazard”. The categorisation is again somewhat easier here, as essentially H and EUH phrases are relevant. In the following, I would like to list some relevant properties and their classification in the column model. The list of all points can be found in TRGS 600 [1].

Very high and high hazard

Substances with very high physico-chemical effects are, for example, explosive substances labelled with H phrases 200, 201, 202, 203, 204 or 205. Flammable gases (H220, 221) or organic peroxides of types A and B (H240, 241) are also classified accordingly. A total of 17 H phrases of different hazard classes are classified as very high hazard. These H phrases mostly belong to the more severe hazard categories 1 resp. A or B. For example, flammable liquids of category 1 (H224) are rated as a very high hazard.
Flammable liquids of category 2 (H225), organic peroxides of types C and D (H242) or aerosols of category 1 (H222 and H229) are some examples of high hazard classification. Various EUH phrases are also considered (EUH014, EUH018, EUH019, EUH044).


Medium and low hazard

As expected, we continue with the less hazardous hazard categories. For example, flammable liquids of category 3 (H226), organic peroxides of types E and F (H242) or aerosols of category 2 (H223 and H229) are classified as medium hazards. Substances corrosive to metals (H290) are also in this level.
Only one H phrase (H229 without H222 or H223) is relevant for the classification of a low physical-chemical effect, this refers to aerosols, category 3. In addition, self-reactive substances, type G, and organic peroxides, type G, can be found here.  Both, however, do not have an H phrase. Another criterion is the flash point of the substance. If this is between 60 and 100 °C, it is a substance of low flammability, which is also considered a low hazard.

Negligible hazard

For some substances the flash point is even higher, i.e. above 100 °C. In this case, the substances are incombustible or only so hardly flammable that this is considered a negligible physical-chemical action.


If you have the safety data sheet of the hazardous substance, it is not difficult to classify it according to the H phrases in the column model. You can also find the EUH phrases or information on the flash point here. It gets more difficult if, for example, an H phrase indicates a very high physico-chemical effect, but the flash point is so high that this is assessed as negligible. In such a case, the highest hazard within the column should be used for comparison with other substances. For more information you are welcome to visit the website of our GefStoff-Profi. There you will see how the GeSi³ software solution supports you in hazardous substance management.

[1]        Technical Rules for Hazardous Substances, TRGS 600, version 29.10.2020, BAuA website.

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