Respirator assigned protection factors has twelve items in the Hierarchy of hazard control (used in industry to minimize or eliminate exposure to hazards).
Hierarchy of hazard control is a system used in industry to minimize or eliminate exposure to hazards. 1. The use of alternative substances which are less hazardous. 2. The substitution of a given substance in a form that is less hazardous, e.g. replacing a fine powder by a coarser powder, pellets, or by a solution 3. The substitution of a process by an alternative process likely to generate lower airborne concentrations of substances 4. Total or partially enclosed process and handling systems 5. Partial enclosure with local exhaust ventilation 6. Local exhaust ventilation 7. General ventilation 8. Reducing period of exposure 9. The introduction of appropriate working practices and systems of work, e.g. to close and store containers securely when not in use 10. Use of monitors and warning devices to give a clear indication when unsafe airborne concentrations are present 11. Good housekeeping 12. Provision of a respiratory protective device program 
