1. Local Exhaust Ventilation

2. Topics

3. How to Catch the Dust

4. Contaminant Characteristics

5. Enclosing Hoods • Used for extracting fast moving contaminant • Normally smaller with high air velocity • Positioned in the direction of contaminant flow • Relatively High Pressure

6. Partial Enclosure • A combination of an extraction hood and booth • Really useful for light dusts that spread quickly once airborne • Typically used for sack tipping and batch weighing • Allows the contaminant to be collected without removing the product

7. Down Draft • Simple operation • Multiple applications. Can be used for dust and fume • Good operator protection • Requires high air volume • Ineffective in the application is not carried out on a bench

8. Canopy Extraction • Predominately used for fume or mist extraction • Requires fumes to rise • Requires larger air volumes • Does not offer local operator protection

9. Positional Hoods • Excellent for small localised extraction requirements • Can be used for fumes and dust • Flexible operation • Only works if the operator engages with the system • Small sphere of operation • Relatively low air volume

10. General Extraction • Used to clear fumes from a large space • Can be adapted to extract from light or heavy fume • Best used in a “push / pull” configuration • Creates a dilution effect • Does not offer local operator protection

11. Fans • Centrifugal Fans • Higher pressure • Fume or dust extraction • Efficient • Axial Fans • Fume extraction and ventilation • High volumes at low pressure • Often poorly applied

12. Filters • Reverse Pulse Filters • Cartridge suitable for high air volumes and low dust loadings • Bag Filter suitable for high dust loadings • 24 hour operation • Multi-Pocket Filters • Low to medium air volumes can deal with high dust loadings • Must be cleaned every 3 – 4 hours

13. Filters • Bag House Dust Unit • Predominately for wood waste extraction. Suitable for dust and chippings • Low cost solution • Wet Collectors • Very good for explosive materials • Good solution for heavy dusts • Low efficiency and difficult to servce

14. Ducting • Spiral Wound • Very cost effective • Simple to install • Can be used on all systems • Difficult to clean • Clip System • Predominantly used for dust extraction • No internal edges, easy to clean • Increased capital cost

15. Ducting Sizing

16. Guidlines

17. ATEX

18. Additional Equipment