When you set up a woodwork, cabinet or joiners workshop it can be a complicated business with innumerable questions needing satisfactorily answers about the activities and processes which go on in it. Most importantly, from a Health & Safety perspective, dust extraction is paramount and a sizeable proportion of the budget should be allocated towards ensuring that a system or equipment is installed which matches both the woodworking machinery and it’s intended purpose.
The topic of wood dust and it’s extraction is an immensely complex area. Woodworking machinery of any sort will produce waste of one sort or another and it’s this which must be managed by selecting the most appropriate equipment. Choosing the correct type of extractor can be confusing at best, with apparently conflicting requirements for collecting waste from a wide variety of woodworking machinery. Initially, it’s recommended that the purchaser should have a clear picture of the type of wood waste produced in the workshop.
Key features of Dust Extraction Systems
- High efficiency Impellor system gives high air flow from a modest motor power
- Manual filter cleaning system, easy to maintain air flow. Axminster Industrial Series extractors incorporate an automatic filter cleaning system
- Choice of inlet sizes for ducting or direct machine connection
- A cartridge filter is good practice and standard for coarse and medium dust. HEPA filter for fine dust such as from a drum sander used with fine abrasives
- All extractors are easy to move around the workshop
- All our extractors come with high capacity waste sacks or drums
Types of Dust Extraction Systems…
A basic Hobby or Trade range chip extractor is designated as a high volume, low pressure (HVLP) machine, generally using a large hose. The mesh size of the filter bag needs to be coarse to allow the high volume of air to pass through it and thus the extractor is NOT suitable for filtering out the very fine dust which is produced from a sanding machine. These machines are rated as 1 (Good) for the sole extraction of chippings from a planer, planer/thicknesser or a spindle moulder. However, add a fine filter bag or cartridge filter (this may be an option or inclusive, depending on the machine) will improve the performance to a rating of 2 (Better) which enables the machine to extract larger particles of sawdust from table and bandsaws. Cartridge filters are fitted with deep pleats to avoid loss of airflow and are suitable to use with machines equipped with a 75mm and above outlet hose. A rotating paddle inside the filter allows the dust collected on the filter material to be shaken loose so that it falls into the sack below, which MUST be made from plastic. For the best results, we recommend using a chip extractor with a higher airflow capacity than is required by the machine it’s connected to.
Fine Dust Extractors
True cyclone extractors, which work on a very different principle to conventional machines, generally separate over 99% of the waste before it passes through the cartridge filter, with performance graded at level 3 (Best). This means that in addition to chippings and sawdust, it will handle finer dust from a sanding machine. Replacing the 1 micron filter (supplied with the machines) with the optional 0.3 micron HEPA filter improves the performance rating to 4 (Excellent) meaning that it will now deal effectively with very fine particles from MDF. A Trade rated cyclone extractor with HEPA filter would form the basis of an excellent ducted system in the workshop, able to deal with all the chippings and dust normally generated. However, in a smaller workshop, these machines take up a significant amount of space and require adequate headroom to clear the top of the motor. In addition, the capacity of the drum may not be sufficient where the machine is in constant use by multiple users, though drum sizes are larger on Industrial cyclones.
This type of machine works on the opposite principle to a chip extractor. A vacuum extractor generates a low volume and high pressure (LVHP) which means that as the vacuum pressure increases, the volume of the air passing through the machine decreases. They are able to deal with most types of wood waste, but the low volume of air passing through the machine makes them unsuitable as the primary extractor in a ducted system except on a 63mm system. They do, however, lend themselves to extracting waste from single dedicated machines where hose sizes are generally much smaller though some vacuum extractors use both large 100mm dia and smaller 32mm diameter hose. The Hobby rated vacuum extractor is rated at level 3 (best) and is suitable to extract from a planer, planer/thicknesser, table saw or bandsaw. With the addition of a stepped hose reducer on the end of the hose, it can be used to extract dust from many power tools. Larger Numatic Trade rated machines may be fitted with an optional internal clip-on HEPA H14 filter module offering a 99.997% @ 0.5 micron capture rate (down to 0.5 micron) and disposable ‘Hepaflow’ bags for the safe and efficient disposal of waste. Where HEPA filtration is incorporated into the machine, the level of performance is rated a 4 (excellent).
Power Tool Extractors
Power tool extractors are small, dedicated vacuum extractors. They are specifically designed to deal with fine dust from power tools and usually use a smaller diameter hose. These should be rated at ‘M’ Class in a Trade environment. Some more general purpose machines are supplied with useful accessories enabling them to be used as a workshop cleaner as well as a power tool extractor. As they’re designed to deal principally with sanding dust, the level of performance is 3 (Best). ‘L’ and ‘M’ Class machines are rated a 4 (excellent), but the small diameter hose means that they’re unable to cope with large volumes of chippings.
When all the woodworking processes have been completed for the day, it’s very tempting to think that the dust generating processes have been finished. This is not the case as a ray of sunlight passing across the workshop will highlight an alarming amount of airborne dust which may be as much as when the machinery was in use. To combat this airborne dust, ambient workshop air filters can be left running quietly in the background, filtering out these very fine dust particles. Suitable for ceiling or wall mounting, or even just ‘stand alone’, ambient air filters will greatly improve the workshop environment. In order to decide on the correct size of the filter, calculate the volume of the workshop and look to circulate the air approximately six times per hour. For the best results, leave the air filter to run for an hour after the machinery has been switched off. Or use the timer function to run the filter after all practical work has been completed in the workshop at the end of the day. Don’t forget to vacuum the filters at least once a week.
There are very strict dust exposure limits for people working in the woodworking industry and, in reality, these are very hard to measure without expensive equipment and trained staff. Even though your static machinery is connected to an efficient dust extraction (LEV) system, there are two other areas where problems of dust exposure are generated: hand sanding (either with power tools or by hand) and cleaning up by brush or compressed air. All of these activities create clouds of extremely fine dust, the size your lungs will not appreciate. By using a vacuum extractor fitted with a HEPA filter, these dusts can be collected at source. This is done by connecting the extractor directly to the dust outlet on a power sander or by using a hand sanding pad with an extraction port. You can use the same machine to vacuum off dusts prior to finishing and with a suitable floor cleaning kit, vacuum the floor. It’s faster and safer, leaves no dust to settle out and makes the workshop floor less slippery as well.
So, what is a HEPA filter and why do I need one?
HEPA stands for High Efficiency Particulate Absorption. A HEPA filter will trap all those dangerous particles that you probably cannot see except in the fading light through the window, but can smell. All wood dusts are a potential danger to health, the smaller dusts being the most harmful. By using a vacuum cleaner or extractor equipped with a HEPA filter you avoid these dangers. The HSE’s guidance is to use a vacuum cleaner or extractor that is at least an M Class machine; these use HEPA filters to meet this high standard.
The dangers of wood dust are very well known and it would be foolish to ignore them. Fortunately these days there’s a huge range of equipment which is able to deal with it. Unfortunately, it’s also a very complex area with a large number of variables that need to be taken into consideration. Removing the wood waste at source is the most efficient method. This method will usually mean constructing a ducted system with a powerful extractor at its centre. An additional vacuum extractor will probably also be required to deal with dust generated by power tools. Plus, you can double it up as a general workshop cleaner.
If you found this article helpful why not take a look at our insight on LEV (Local Exhaust Ventilation) and learn what extractor is best for your workshop.