Hazard class - the conditional value of the harmful effect, which is established in accordance with regulatory industry documents. For different objects - for chemicals .
The hazard class of harmful substances is a conditional value intended for a simplified classification of potentially hazardous substances.
The hazard class of harmful substances is established depending on the norms and indicators. Indicators according to GOST 12.1.007-76  are indicated in the following table. The assignment of a harmful substance to a hazard class is carried out according to an indicator whose value corresponds to the highest hazard class.
|Name of indicator||Norm for hazard class|
|MPC of harmful substances in the air of the working area, mg / m³||more than 10.0||1.1-10.0||0.1-1.0||less than 0.1|
|The average lethal dose (LD 50 ) when introduced into the stomach, mg per 1 kg of body weight||more than 5000||151-5000||15-150||less than 15|
|The average lethal dose when applied to the skin, mg per 1 kg of body weight||more than 2500||501-2500||100-500||less than 100|
|Average lethal concentration in air, mg / m³||more than 50,000||5001-50 000||500-5000||less than 500|
|Coefficient of possibility of inhalation poisoning (CVI)||less than 3||29-3||30-300||more than 300|
|Acute area||more than 54.0||18.1-54.0||6.0-18.0||less than 6.0|
|Chronic area||more than 10.0||10.0-5.0||4.9-2.5||less than 2.5|
Definition of hazard class
Initially, the experimental determination of the toxicological properties of substances underlies the assessment of their hazard class and other derived characteristics. For greater accuracy, the assessment is recommended based on the results of toxicity studies in relation to two to three species of animals or test cultures (strains, etc.).
The calculation method is based on a database of toxicological properties of individual substances in combination with a fairly complete analytical study of the object. In practice, the application of the calculation method is associated with a number of limitations that are not consciously taken into account, and is used only because of the high cost of direct toxicological research of the object.
- Maximum permissible concentration
- Lethal dose
- Hazard symbols