A 1-hp single-stage collector can handle any machine in my shop The biggest sawdust producer in my shop is a in. The benefits are significant. First, I would like to review your research findings if they provide examples of explosions caused by non-grounded PVC ducting. Collectors ranging in size from 1 hp to 2 hp have impellers fans sized from 10 in. From the Table determine the velocity FPM woodworking shop dust collection design report your system for the type of dust that will be produced.

Thanks for all your help this week. Since upgrading to a more powerful dust collector I have gotten some minor shocks at the tools during the dry MN winter, but nothing to be concerned about.

I did receive a major shock when I overfilled my plastic dust collector and ran it for a while before I realized it. All those wood shavings swirling in a plastic funnel was a wicked combination. So I wrapped a ground wire around the dust collector a couple times and grounded it. I have overfilled the dust collector a few times since, but no more shocks of that magnitude. Thanks for this. Appreciate you sharing this.

Hi, many thanks for the informative discussion. I totally agree with the comments on gentle curves and corners and have found that this minimises chances of clogging the duct on flexible systems.

I am in the process of setting up a new workshop and will be looking at a PVC rigid pipe system this time. As I will probably end up with a right-angle run with the dust collector at the right angle, one on each arm should suffice. At his stage, I will probably purchase a 2Hp dust collector. I am inclined to include it at the design stage as the ducting will be less accessible after construction.

Thanks for the comments. I agree; if you plan to ground the ducting, it would be far better to do it as you install it rather than waiting until later. Thanks, one of the best and simplistic explanations on the web. I have a powermatic model 73 with in inlets would using 6in main line over power the unit? Hi Frank, thanks for the kind words. The Powermatic 73 is a 1. Essentially this would reduce static pressure in the overall system with increased air speed right at the tool itself.

I would keep the use of flex pipe to an absolute minimum. Also, I suggest installing a couple extra elbows at various places in the system that can be used to inspect the ducting for dust build-up. Great advice! I am going to use a 5hp Super Dust Gorilla so as never to be wanting more power. I want to use pvc ducting and your article gives me a good start. Be sure to get the stuff with the thinnest walls that you can find. Hi Paul- Please see the comments I have left on grounding the dust collection system.

Feel free to comment, this is an important subject. Hi Scott, thanks for sharing your thoughts on this. It is good to hear that there is continuing research on this important topic. I have not personally done scientific analysis in this area, but anecdotally I am not aware of a prevalence of explosions due to non-grounded PVC ducting.

If your research findings or demonstrative evidence are available on-line please feel free to post a link so that other readers can view this information to help them make an informed choice in this area as they set up their dust collection systems. This is the beauty of on-line articles; the ability to keep the discussion going long after the articles are published. I love it! Without going on too long here, see the directions from Shop Fox above. Most if not all collectors come with a warning like this.

Usually when we see a cloud of dust in the shop, we think about not breathing in too much of it. The real danger is having a spark occur at the same time. One of the other members here wrote that he saw and felt a very large spark when he was dumping his bags.

This would be easily able to cause an explosion if the right amount of dust was floating in the air at the time. Grounding your existing ductwork would not be expensive or time consuming. Its like having ABS in your car, you might not know how many times it saves you. But you surely will know when it does not. These are good points, Scott, and I understand the theoretical risk; wood dust is flammable, and under the right conditions it can ignite.

The comparison to the health risks of breathing dust and driving dangers are fair to an extent, although there is a lot of evidence to suggest that those items in fact can be statistically linked to health problems and injury. With the prevalence of PVC used in dust collection systems around the US, if the risk is in fact statistically significant there should be numerous examples of explosions resulting from this.

I have seen this topic debated in woodworking forums for nearly two decades, but I have not seen any compelling evidence to support the theoretical risk. First, I would like to review your research findings if they provide examples of explosions caused by non-grounded PVC ducting. If there is emerging data in this area then I want to be informed, and I believe that there will be widespread interest across our readership as well.

Secondly, if you have a means of demonstrating the explosiveness of wood dust in simulated small shop ductwork, I would like to collaborate with you to produce a video on this topic if you are interested, as this would be received extremely well by the woodworking community. Thanks again for sharing your thoughts on this. After doing more research, I will admit that you are correct in most cases.

My concern is not with dust that is moving inside the duct, but with the static that is discharged when nearby events such as cleanup with an air hose, sweeping, or emptying dust bags creates a dust cloud. This supports the use of PVC as safe. Be careful out there. Re: Grounding- I have worked in an industrial woodworking environment for 35 years. There is almost zero danger of an electric shock to a human, but very big hazard of having a dust explosion!

That tiny static shock you might feel is plenty to cause a cloud of dust to blow up. Moving air causes enormous amounts of static electricity. Typical metal ductwork can dissipate this fairly easily, as it is often attached to metal building structure parts.

PVC can not ground by itself, and the fact that it is a good insulator increases the static buildup much higher than metal. If you already have PVC, at least run a bare copper wire along the outside of the duct to ground.

It would be better if it was on the inside, but this is not always practical. In many areas it is strictly against code to use PVC for this purpose. Good luck, and work safe. Here is an example if instruction from Shop Fox, a popular portable dust collector manufacturer. System Grounding. Ensure that each machine is continuously grounded to the dust collector frame with a ground screw, as shown in Figure While I agree with most of your article, I strongly caution any use of PVC pipe in a wood dust collection system.

Just because you may not have had any issues in the past does not mean that you are capturing the dust safely. My suggestion is to use only metal duct, make sure the dust collector will provide 4, Fpm feet per minute velocity in the duct and only capture wood dust with your dust collector.

These simple steps will drastically reduce your dust explosion risks. Love the system but for one thing: Insurance companies Pretty sure every single one of them will not cover a house fire if there is a non metallic DC system and they can claim that the fire started there.

They allow no substitutions like ground wires straps etc. They only cover metal ducts that are grounded. What are the odds that a DC will cause a fire? Maybe remote. PVC duct systems are common in hobbyist woodworking shops but users are encouraged to perform their own due diligence to verify their insurance coverage. Love your DC. Love your approach.

I learned that no insurance company will cover a fire that they can claim arose from a dust collection system not made from grounded metal piping. Put aside the whole fire risk or not question and ask the other question of insurance coverage. The problem is that insurance companies have an unshakable conviction that non metal ducting is an unreasonable fire hazard. You answered several questions I had about setting up a dust collection system in my shop.

Tahnks for writing the article, it was very good for me. I dont know if you can answer my question. I want to make piping for my cfm dust collector.

At the output of the collector, there will be 2 lanes. The left lane will be on 4 inch pvc duct for about 14 feet with about four 45 degrees elbows. The right lane will be on 6 inch pvc for about 30 feet with a 5 feet of vertical duct on the 30 feet with about four 45 degrees elbows. At the end of the 30 feet, it will have about 16 feet of 4 inch pvc to reach the tools. Only one tool at the time will work on this collector. Can you tell me what dust collector this is?

Would such a small system work, in your opinion? Hi Jim. It would collect some of the heavier debris but would not do much to collect the fine dust that causes health problems. I would recommend at a minimum a 1. I incorated 12 v switch system to start the system automatically. Use metal pipe with whatever fittings you choose to afford and make sure to ground it in at least one place. Blast gates are setup at each tool, and you only have it open when you are using that tool; all other gates remained closed.

That provides the full concentration of suction right at the tool you are using, to get you maximum dust collection from that tool. If you left all of the gates open you would have very poor air flow at each tool. Hi Rick. Hi Timothy. Wish I had read a a long time ago. I have learned all this and more by going it alone with my first system. On my third now and it works great. Not quite done yet but what a difference hen you get big pipes and a powerful blower.

John the Handyman in Las Vegas. I have an 8 foot stroke sander as well as a small belt sander and blow up sander, would I need to run separate runs to each of these. They are side by side in my shop. The stroke sander is the worst tool for dust and not sure what is the best way to set up the collection piping on it. I am in the country with a bush beside my shop so I plan on piping directly to the out side with the out let. Hi Ron. Thanks for reaching Woodworking Shop Dust Collection Design Uk out with your questions.

I would recommend a separate drop for each tool. In other words, you are better off if you have a single blast gate designated for each tool, and therefore each tool gets the full air flow from the dust collector. When an ad says a collector is rated at 1, cfm, what does it mean? Not much, really. Cfm stands for cubic feet per minute, a measure of the volume of air moving past a point of reference.

The cfm figure needs to be put in the context of the amount of resistance, or friction, present called static pressure, or SP. Air moving through duct or hose encounters resistance, just as a person would slipping down a water slide. The more bends and bumps, the slower the ride or the lower the air velocity and volume. Many manufacturers rate their machines without bags or duct attached. While trying out a number of dust collectors, I measured their performances under real working conditions, using flexible hose, PVC pipe or metal duct in my sq.

I also measured collectors hooked up to a straight piece of 6-in. Collectors ranging in size from 1 hp to 2 hp have impellers fans sized from 10 in. All things being equal motor speed and impeller design , a Woodworking Shop Dust Collection Design 10 bigger impeller coupled with a bigger motor will move more air than a smaller pairing. There are some differences among collectors; to learn more, ask a manufacturer for an impeller performance chart. As soon as any collector is hooked up in the shop, performance declines in relation to the length and type of hookup.

Materials that affect airflow. The metal elbow top , which is designed for central dust-collection systems, has a gentle sweep, which lowers resistance to airflow. Plastic PVC pipe has a tighter-radius bend and restricts airflow more. Ribbed flexible pipe also disturbs airflow, up to three times as much as metal.

Hooked up to two 6-ft. With a larger upper bag, I found that the cfm readings were not compromised. But if you happen to vacuum up any offcuts, they will make quite a racket rattling around in a metal trash can. Although many woodworkers, myself included, have used PVC drainpipe for duct without mishap, experts warn against using the material. The connectors elbows and wyes restrict airflow, and the material builds up a static charge, which may cause a spark and set off an explosion.

Running grounded copper wire inside the pipe reduces the hazard. Use PVC at your own risk. Metal duct and fittings are obviously better and will also last longer. Your collector will work more efficiently, and so will you. Quick View. Add to Cart. Jet - Vortex Cone Dust Collector, 1. View All Dust Collection.

You must be logged in to write a comment. Log In. Find a Store. My Account. My Cart. Go to Home Page. Mobile Navigation. Same Day Shipping Find a Store. Search Go. Topics Cabinetry. Choosing Hardware. Dust Collection. Friends of Woodcraft. Getting Started with Woodworking. Make Something. Pen Kit Reference Chart. Calculate the SP of all branches to determine which has the greatest SP. Only the branch with the greatest SP or resistance is added to the total.

You can use the charts on pages to assist in your calculations. You now have the information you need to specify your dust collector.

The above example is for a small system with few variables. It is recommended that for larger systems a professional engineer be consulted to assure that the system is properly designed and sized. If the dust collector is located in a separate enclosure, it is essential to provide a source of make-up air to the shop to prevent a down draft through the flue of the heating system.

If this is not done, carbon monoxide poisoning could result. If a return duct is necessary from the dust collector, it should be sized two inches larger than the main duct entrance and its SP loss added into your calculations. Some dust collection units may not include fan curve information that shows CFM or Static Pressure variables. We do not recommend procuring collector equipment without this information.

Dust suspended in air has a potential for explosion, so it is recommended that you ground all of your duct runs, including flex-hose. If your system has areas where long slivers of material could possibly hang-up and cause a clog, install a clean-out near that area.

Many types of dust, including many woods are toxic, so take special care to choose a filtering system that will provide Woodworking Shop Dust Collection Design 3d Model optimal safety. Designing an Efficient Dust Collection System. Designing Your Dust Collection System There are two phases to designing your dust collection system: The first phase is sizing your duct work for adequate volume and velocity of flow for the type of dust you will be creating; and the second phase is computing the static pressure SP of your system to determine the size and power of your dust collection unit.

You will also need to familiarize yourself with the following concepts: CFM Cubic Feet per Minute is the volume of air moved per minute. FPM Feet per Minute is the velocity of the airstream.

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