Exposure limits: how to read the number
8 hours, short-term, ceiling value and the letters E, L, H and K
Introduction
An occupational exposure limit is the highest concentration of a substance in the air that you may breathe in at work. The limit values are in BEK nr. 613/2026. If they are not complied with, this can be punished with a fine or imprisonment for up to 2 years (§ 4).
Three kinds of limits
- 018-hour value: the average over an eight-hour working day.
- 02Short-term value: the average over 15 minutes.
- 03Ceiling value: must not be exceeded at any time.
Where it is stated in the list, the short-term value is twice the 8-hour value (§ 3, stk. 2).
The letters
| Letter | Meaning |
|---|---|
| E | The exposure limit is set by the EU |
| L | Ceiling value: must never be exceeded |
| H | The substance can be absorbed through the skin |
| K | The substance is considered to be possibly carcinogenic |
Several substances at once
If there are several substances in the air at the same time, they must be added together. For each substance, you divide the concentration by the exposure limit. The sum must not exceed 1 (§ 3, stk. 3).
Examples from the trades
| Fabric | Exposure limit (8 hours) | Letters | Where you encounter it |
|---|---|---|---|
| Quartz, respirable | 0,1 mg/m³ | K | Bricklaying, concrete |
| Wood dust, inhalable | 1 mg/m³ | E, K (EU limit value, carcinogen) | Carpenter |
| Asbestos | 0.003 fibres/cm³; 0.002 from 21 December 2029 | E, K (EU limit value, carcinogen) | Demolition |
| Bly | 0.03 mg/m³ | E | Renovation |
| Diisocyanates | 0.01 mg NCO/m³; 0.006 from 1 January 2029 | H | PUR, varnish |
| Styrene | Ceiling value 25 ppm / 105 mg/m³ | L, H, K (ceiling, skin, carcinogen) | Fibreglass |
| Formaldehyde | 0.3 ppm / 0.37 mg/m³; short-term 0.6 ppm / 0.74 mg/m³ | E, K (EU limit value, carcinogen) | Glue, wood-based panels |