Ventilation and extraction during hazardous work
How is the air cleaned before it reaches your lungs
Protective equipment is often the first thing you think of when it comes to protection against hazardous substances. But before you reach the protective equipment, there is a whole layer of measures that deal with preventing hazards from reaching the person working — and ventilation and extraction play a central role here.
§The STOP principle: the order matters
Work environment work is based on a fixed sequence often called the STOP principle: Substitution (replace the hazard with something less hazardous) Technical measures (shielding ventilation extraction) Organizational measures (planning work arrangement) and finally Personal protective equipment. Ventilation and extraction are part of the technical layer — what you put in place when the risk cannot be eliminated entirely but before you rely on individual protective equipment.
§Types of ventilation
| Type | How it works | Usually used for |
|---|---|---|
| Procesudsugning/punktudsugning | Faraday cage effect describes how the electric field is shielded in deep, internal corners so powder has a harder time getting in there. | Welding, spraying, grinding and other work with a clear emission source |
| General space ventilation | Replaces air in the entire room or area over time. | Background Levels of Vapours Where There is no Single Point Source |
| Supplied air respiratory protection | Delivers clean air directly to the user, regardless of the room's air quality | Situations where neither process exhaust nor room ventilation can bring the concentration sufficiently down |
§Ventilation does not replace protective equipment — it supplements it
Even the best ventilation rarely eliminates all risk. When working with epoxy isocyanates or asbestos dust ventilation is therefore always supplemented with proper personal protective equipment — but the order of the STOP principle means you should not rely solely on personal protective equipment if a technical solution could have eliminated most of the danger beforehand.
§Practical pitfalls
- 01Extraction that is incorrectly positioned relative to where the vapors actually rise or spread.
- 02Doors and gates opened so planned airflow is disturbed.
- 03Filters or channels that are not maintained so the effect diminishes imperceptibly over time
- 04Confusing "there is a ventilator" with "ventilation is sufficient for exactly this task"
“The best protection is the one that removes the hazard before it reaches you — the protective equipment is the backup, not the plan.”