Hi Wayne

Question what type of cutting are you doing, ie what's the product (wood, stone etc) as that will dictate the type of LEVdust control you will. There are systems in this area that we know work well but need to know what the material is, also is this portable equipment or fixed?

One way to control it is to try and reduce how much you generate. Having high quality sharp blades is a good step. This will also help with the noise it makes.

good point - mainly framing timber, but at times we cut cement sheeting and other like cladding's

good point - thanks

Hi Wayne

Thanks for that. Okay there are differences in the weights of the dust generated. I suggest that you get in an occupational hygienist that can advise or a LEV engineer as it looks like you would need someting built as opposed to off the shelf.

Hi Wayne, is your gear primarily workshop/factory based, or site/installers gear? Have you found Worksafe's guidance page on LEV LEV Guide
Here's a link to UK HSE, which might be usefulLEV Processes they have some calculator tools that might be handy too LEV Assesor Calculators

Other random LEV Links
http://www.itm.co.nz/dustcontrol
https://www.vent-tech.co.uk/resources/downloads/

Hi Wayne, this link has some good point around bench saws
https://www.youtube.com/watch?v=Ky8y2jDk6i8

The movement and extraction of particles in the air is a specialist field and so important to get right particularly when controlling probable carcinogens. As per Derek's advice, seek the guidance of a suitable qualified person rather than taking a punt :)

Getting it right first time will reduce your monitoring costs over time as well!

The UK HSE reference that Steve H provided is probably the most useful. It is large but very comprehensive and accurate. Far too many contaminant extraction systems are designed by heating and ventilating engineers, with the ductwork designed and installed by sheet-metal engineers. The requirements for heating and ventilating and the requirements for extraction of airborne contaminant are substantially different. Ventilation for contaminant control is a specialised subject. Anybody engaging a supplier of ventilation equipment should insist that it is a performance-based contract so that payment is made only when the system performs to a required standard.
A good principle to keep in mind is that the capture and transport velocity of the airflow is critical. Airflow is typically based on the rating of the fan, i.e. the volume of air that can pass through fan blades generally measured in metres per second. The further away from the Capture point the fan is situated the lower the capture velocity will be, due to friction and turbulence in the ducting caused by bends, distance, and undulations, e.g. ribbed ducting. At the opening of the ducting into the hood, or room if there is no hood, the airflow rate can be measured. However, the flow rate reduces by 90% every duct diameter distant from the opening. So the airflow rating of the fan doesn't automatically equate to the capture velocity.
For capturing contaminant generated by hand tools performing the work in a semi-enclosed hood, or otherwise with either an attached capture system or movable extraction system that can be positioned close to the workpiece are the primary options.

I've been experimenting with a dust lamp to make visible what is invisible and then photograph the dust (the Tyndall's beam effect). This avoids the immediate need to carry out personal monitoring and results have been quite dramatic. In one case I caught fibres "on camera" as well as dust and was able to show how quickly the extraction system efficiency reduced as the hood was moved away from the work.
This does not remove the need to carry out personal monitoring but does give a quick and effective way of showing managers and workers the problem.
The dust lamp I'm using is actually a Ryobi torch with a high intensity halogen bulb (do not look into the light!). I'm planning to compare/contrast with a similar but old torch that was sold as a dust lamp.
An HSE note on the dust lamp is at http://www.hse.gov.uk/pubns/mdhs/pdfs/mdhs82-2.pdf.
If others are interested in this work I'm happy to collaborate "off line" and work up some simple guidance with case studies.