Questions regarding hydrogen fluoride hazard sources
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Today, while studying the standards *“Identification of Major Hazard Sources for Hazardous Chemicals”* and *“Guidelines for the Implementation of the Hazardous Chemicals Catalogue”*, I encountered a problem. The guidelines list two substances: hydrogen fluoride and hydrofluoric acid, both of which have the same CAS number, namely 7664-39-3. This means that both are considered hazardous chemicals. However, when looking up the critical quantities in the “Identification” section, only hydrogen fluoride has a specified critical quantity (1 ton), while hydrofluoric acid does not have one listed. Can it be assumed then that intermediate tanks containing more than 1 ton of hydrofluoric acid do not need to be classified as major hazard sources?
According to the \"Classification Information Table for Hazardous Chemicals\", the hazard category of hydrofluoric acid is \"Acute Toxicity – Dermal, Category 1\"; this corresponds to Table 2 of GB18218, with symbol J2 and a critical amount of 50 tons
Hydrogen fluoride and hydrofluoric acid are two different substances; I’m not sure why they share the same GAS code. One is a gaseous acid and the other is a liquid acid; their levels of danger differ greatly
I also think there is another reason for classifying Table 2’s 50t acute toxicity – dermal route, Category 1 J2: the alias column next to hydrogen fluoride in Table 1 is left blank. If the standards consider them to be the same substance, then aliases would be listed, just like for other substances in Table 1; after all, hydrofluoric acid comes in different concentrations
What really troubles me is the critical amount for nitric acid. Table 1 shows that the critical amount for nitric acid with a concentration of over 70% is 100 tons; so does this mean that nitric acid with a concentration below 70% does not qualify as a substance that constitutes a major hazard? Nitric acid with a concentration below 70% also has oxidizing properties
Nitric Acid also contacted the manufacturer recently; the only solution for the issue you mentioned is not to specify 70% directly when going through the project procedures, for reasons that are obvious to you. :lol
There is actually another issue here: the concentration of hydrofluoric acid is not specified. If the concentration is too high, hydrogen fluoride gas will escape; in such a case, the category should probably not be J2 but rather J1, and the critical amount would then be 5 tons.
Another point is that the specifications do not specify a specific concentration.
Since it is the same CAS number, the design institute is likely to classify it as hydrogen fluoride, which results in this device becoming a major source of hazard.
I’m also struggling with this. According to Article 4.2.3 of 18218-2018: “For hazardous chemical mixtures, if the mixture and its constituent pure substances belong to the same hazard category, then the mixture is treated as a pure substance, and calculations are done based on the mixture as a whole.” If the mixture and its pure components do not belong to the same hazard category, their critical quantities should be considered according to the new hazard category. ” According to the classification information table for hazardous chemicals, anhydrous hydrogen fluoride and hydrofluoric acid fall under the same hazard categories: acute toxicity – oral, Category 2*, acute toxicity – dermal, Category 1, acute toxicity – inhalation, Category 2*, skin corrosion/irritation, Category 1A, and severe eye damage/eye irritation, Category 1. Should hydrofluoric acid be considered equivalent to anhydrous hydrogen fluoride as a pure substance, and should the calculation be based on the amount of 1 ton as specified in Table 1? I seek guidance from experts.