Pushfit soil pipe as dust extraction

[Retired]

Hi,

https://www.hse.gov.uk/pubns/wis32.pdf

Page 2 Please look under ductwork.

This morning I intended to email our local fire department sending them a link to this thread requesting their expert recommendation and guidelines but looking at the mixed replies it appears a number of members are saying it's safe to use plastic ducting for wood chip/dust extraction. Home workshop fires/explosions simply don't feature on mainline news but are generally in local news as are household gas explosions. HSE clearly state "USE ONLY CONDUCTIVE MATERIALS FOR DUCTWORK" If you disagree and go ahead to use plastic ducting and suffer a fire/explosion then at least I and others like Mike Jordan have taken the time to post the dangers.

I wonder how many members have actually witnessed the power of an explosion in a confined space; I have during my time working down a deep coal mine whilst a deputy was shot blasting.

Many years ago my younger brother at the time living in a flat in Wakefield awoke to find the front of the old Victorian building missing; huge calor gas cylinders were stored in the basement these for cooking purposes. Fortunately there were no casualties; this explosion made it as far as local TV but not national TV.

Four dead in UK wood mill explosion

Kind regards, Colin.

 

[NetBlindPaul]

Just because there are no incidents that can be found for DIY setups causing explosions or fires, this does not mean this can be ignored.
The hazard is real.
The risk is real.
You might even fine that in time insurers will clamp down on home workshops.

I really hope this does not happen, as likely I will have to give up my commercial workshop soon and move my machinery home, I have a mix of wood working, very basic, a tidy Harrison lathe and a Bridgeport, plus various welding equipment.
Unfortunately, I’m writing this from a hospital bed having been paralysed from the navel down by cancer, in the last few weeks. So I don’t think I will be in a position to continue renting the workshop without income.

 

[Doug B]

I personally don’t use plastic ducting other than flexible hose & whilst not denying static charge can cause explosions it’s interesting that companies like Camvac produce a ducting made from plastic tubing & they aren’t the only ones.

Surely these companies aren’t taking the suggested risk without any thought of possible liability, I fully understand that flour can & does easily ignite but surely as woodworkers we aren’t producing such fine dust in relevant quantities to cause an explosion as linked to by Retired?

 

[NetBlindPaul]

In a business ”undertaking” the law requires that the LEV system is CE/UKCA marked in its installed condition, that means it must comply with the EHSR’s of the MD/SMSR.
This is not an option, failing to do this is illegal.
Obviously in DIY this does not apply.
However in the event of a domestic failing, the insurance company loss adjusters would be looking for a way to avoid paying out.
Being an expert witness myself, I would simply be looking to the ducting being plastic and I would then look into the guidance around that and the previous commercial incidents nd the science behind the ignition energies to illustrate that the plastic duct was unsuitable and that the user choosing this obviously did not understand the hazards.
Then I would illustrate that LEV must meet the. MD/SMSR to be legal to be placed on the market, which includes own use.
After that it would be up to the insurance company or court to decide, if this was applicable to a DIY scenario.
After all the machinery you buy must comply to be legal.

The suppliers at the moment can sell what they like, you. only need to look on the various online auction sites and similar even those with .co.uk domains, those based in China are even more of a risk.
It is the designer and manufacturer of the LEV system who is responsible for compliance.

One last point, if one were to purchase something from one of the Chinese auction or sales site, or come to that, any site selling outside the UK/EU, then even as a private individual you then become the importer with all of the legal obligations of that role. Basically you take on the responsibility as the manufacturer, and become legally liable for the compliance of the product in the UK/EU.

The fine details of this moving forward are subject to the BREXIT agreement, however, SMSR is UK law and the EHSR’s are identical to the MD, as is the rest of the legislation I have quoted, and changes will. depend on the “agreement”

 

[Retired]

Hi,

I'm sorry to learn of your serious health problem Paul and wish you a full and speedy recovery also a very happy New Year.

Downsizing your workshop can be good as in my case. We have our garage directly beneath our detached bungalow but now it's a fully kitted workshop with the car outside on the driveway. Over the years I collected lots of big heavy machines including Dominion woodturning lathe; Colchester Triumph engineering lathe; Startrite combination woodworker and Startrite industrial Volant 24" bandsaw; I reached the point I had so much machinery I struggled to work bumping into them all the time so I downsized; I can still carry out any woodworking or metalworking I'll ever need to do in a home workshop; the machines I had were way over the top so now I've got smaller machines and even added to them; some are on wheels/casters but I can now work in reasonable comfort; one real hazard is if I'm kneeling down under the radial arm saw I forget the arm is above me; OUCH.

I was brought up with huge industrial machinery and still think bigger is best but I really didn't need so much power; my current machinery and tooling are all excellent quality and I enjoy owning and using them; my sawbench is home made at 4hp and my bigger machines were bought mostly as scrap and rebuilt by me to suit my needs with modifications carried out. I'm not a fan of modern tinny machinery covered in self adhesive safety labels or fitted with guards that actually make the machine feel unsafe; one very important thing seems to be missing these days its called common sense; we now need safety labels stating not to poke a finger into a moving cutter; still we also need road signs stating "No road markings".

I agree with all members who are against the use of plastic for woodworking extraction.

ComDust victim awarded $39.7 million

Just a final word from me regarding using plastic ducting; it's your choice.

Kind regards, Colin.

 

[Sandyn]

Unfortunately, I’m writing this from a hospital bed having been paralysed from the navel down by cancer

Hi Paul. There but for the grace of a god, go I. I am very sorry to hear of your illness. I hope you have a full and speedy recovery and get back into your workshop soon!!

 

[Sandyn]

Health and Safety is also a guise for transferring responsibility. Companies have to follow HSE guidelines to remain legal (so they can't be blamed), but the problem with something like static sparks in plastic ducting is that the real risk to domestic users is extremely low, Just taking a common sense approach, the internet isn't full of accounts of people having burnt their house down because of a spark in their dust extraction, but in industry, because it's a recognised risk, the HSE have to legislate. We end up in many cases legislating for the tiny probability of something happening, the the whole population have to change their habits because of an almost zero risk. For commercial ventures, they just have to abide by the law.
For home users, they have the ability to review all the information and make an informed decision, which suits what they do and their system. In my particular case, I don't think there is a risk, so I will continue to use the plastic ducting I have, but I have taken note of everything said here by people with huge experience in this area and respect that experience. Also I now know that spiral metal conduit can be purchases as cheaply as plastic, so if I eventually upgrade from my use of cheap plastic stuff, It would be stupid not to take note of what people on here have said. I would chose metal ducting, similar cost, so why not.

 

[dzj]

An interesting read from a US forum:
http://www.woodcentral.com/articles/shop/articles_221.shtml

 

[Inspector]

Paul I wish you a speedy recovery.

Pete

 

[gregmcateer]

Paul,
Sincere best wishes and I too hope you a full and speedy recovery.
Greg

 

[OldWood]

I've followed this discussion with considerable interest. I am not a tub-thumper as I feel one or two here are, though I would like to take the general advice which seems to be to go metal.

But I won't - certainly initially - as I don't have a system yet installed and I really don't know how I am going to install it nor the best runs. The logic therefore from that perspective is to go plastic as I can go along to the local builders merchant and buy all the bits off the shelf as I need it. Go metal and I would be collecting carriage costs, the design would need to be right from day 1 which would mean the task may never actually get started.
Rob

 

[mpcpba]

An interesting read from a US forum:
http://www.woodcentral.com/articles/shop/articles_221.shtml

An excellent well researched article which lays out the real risks clearly. Many thanks for finding it.

 

[NetBlindPaul]

An interesting read from a US forum:
http://www.woodcentral.com/articles/shop/articles_221.shtml

I have no issues with the science and principles of article.

I do have an issue that the “codes“ quoted which are not applicable in the UK/EU.
The requirements in the UK/EU are not for explosion venting.
The UK/EU requirements are that the potential for fire or explosion must be engineered out, such that they cannot happen.
Explosion vents may be fitted, but, are superfluous, if the equipment meets the EHSR’s.
If the explosion vents are required then the equipment is not legal for placing on the market.

One must consider that in making your LEV system in your home workshop,you are designing and manufacturing a piece of equipment that falls into the requirements of the MD/SMSR.It also falls under Annexe V of the legislation and is accompanied there by devices to control electrostatic discharge, which also must be controlled and limited by the legislation such that it cannot pose a hazard.

This is a typical difference in legislation between the USA and the UK/EU and many other areas which directly adopt ISO and IEC standards.
The USA allow catastrophic events, then try to mitigate the consequences, the rest of the world tends to require that the potential for catastrophic events is engineered out.

One only need look at the use of PPE, comparing the UK & the USA, in the UK PPE is a last resort after all other engineering measures have been applied to minimise the risk. In the USA, it is almost the first choice.

US machinery built to US standards and imported into the UK that I have inspected for compliance with the MD & the relevant harmonised standards was no where near compliant, nor even safe. The electrical safety was 30 years behind what would be expected in the EU.

Now I realise that these comments are centred around the legislation as applied to a business undertaking.
However, the law does not draw a distinction as to whether the machinery is manufactured as part of a business undertaking or not, it could probably be argued either way, and an insurer would likely push for legal compliance in the event of an issue.

The Directive states as follows:

Article 2
(i) ‘manufacurer’ means any natural or legal person who designs and/or manufactures machinery or partly completed machinery covered by this directive and is responsible for the conformity of the machinery or the partly completed machinery with this Directive with a view to its being placed on the market, under his own name or trade mark or for his own use. In the absence of a manufacturer as defined above, any legal or natural person who places on the market or puts into service machinery or partly completed machinery covered by this Directive shall be considered a manufacturer;
...
(k) ‘putting into service’ means the first use, for its intended purpose, in the community, of machinery covered by this directive;

The directive also contains a list of safety devices in Annexe V which includes LEV and devices to control electrostatic discharge. Which require special consideration under the directive.

I realise that this is potentially subject to change by the “BREXIT” agreement, however, until this is deciphered we will not know and the last advice we had from BEIS was that initially nothing would change as it is mirrored as UK legislation.

However the point still remains whether this legislation would be extended to a DIY scenario. I think that will require a serious event, which I am sure we can all agree that we do not want to happen.
If it did then the subsequent court case would create the relevant case law and legal precedent.
The one thing I am unsure about is if a legal case has taken place with regard to other DIY machinery which could have already set a precedent.

 

[Misterdog]

It's much easier to use metal ducting than push fit plastic, unless you remove the rubber sealing ring. Chamfering the cut end of the plastic and lubricating aids initial insertion, but try taking it apart a few months/years later. It sets like glue.
Metal ducting from a dedicated ducting supplier costs around the same, though you need an angle grinder to cut and tape to seal.

I have used plastic 'soil pipe' extraction for around 20 years, in one of my shops and have metal in another.

I think there are far easier ways to cause sparks in ducting systems than static.
Metal fragments in chipboard, and bullets in solid timber spring to mind.
If cutting very hard wood which traps the blade enough heat can be generated to ignite the chippings.

How many static explosions crop up in a Google search ?

This video seems well balanced on the subject, though the explosion believers will not like it.

 

[Walcote]

Is there much consideration for 4" vent pipe? I recently made a system with 1 10m run and 3 drops and the 4" vent pipe was at least 50% cheaper than any other solution I looked at such as Soil Pipe and Galv. I was worried about static so have a bare copper wire running internally the length of the duct to ground and I have had no shock personally and no indication of static build up so far. It took a little more invention as there are not so many off the shelf dust extraction parts for it so I 3D printed and Laser cut gates and various fittings but they could easily have been done with basic woodworking skills. If anyone is interested, let me know and I'll post the 3D files online. I will be replacing the remaining 90 degree turn with 2 45s when I get a chance. The only downside was I couldn't find an unequal Y joint so it has T joints for the drops. Not ideal but it works brilliantly with whatever drop in efficiency not causing a problem. I'm interested to hear what others think of the solution and hope no one is going to tell me the big reason it was all a bad idea!!

Please excuse the mess! I am sorting through a bunch of stuff.

 

[Heluvaname]

It's much easier to use metal ducting than push fit plastic, unless you remove the rubber sealing ring. Chamfering the cut end of the plastic and lubricating aids initial insertion, but try taking it apart a few months/years later. It sets like glue.
Metal ducting from a dedicated ducting supplier costs around the same, though you need an angle grinder to cut and tape to seal.

I have used plastic 'soil pipe' extraction for around 20 years, in one of my shops and have metal in another.

I think there are far easier ways to cause sparks in ducting systems than static.
Metal fragments in chipboard, and bullets in solid timber spring to mind.
If cutting very hard wood which traps the blade enough heat can be generated to ignite the chippings.

How many static explosions crop up in a Google search ?

This video seems well balanced on the subject, though the explosion believers will not like it.

I was thinking that using the solvent weld soil pipe socket fittings, and just pushing together without glue would seem to provide a pretty good seal/fit rather than the rubber gasketed "push-fit" system.
I guess you could also PTFE tape around the joints if necessary, allowing them to be easily taken apart for blockage et later if needed.

 

[Heluvaname]

Is there much consideration for 4" vent pipe? I recently made a system with 1 10m run and 3 drops and the 4" vent pipe was at least 50% cheaper than any other solution I looked at such as Soil Pipe and Galv. I was worried about static so have a bare copper wire running internally the length of the duct to ground and I have had no shock personally and no indication of static build up so far. It took a little more invention as there are not so many off the shelf dust extraction parts for it so I 3D printed and Laser cut gates and various fittings but they could easily have been done with basic woodworking skills. If anyone is interested, let me know and I'll post the 3D files online. I will be replacing the remaining 90 degree turn with 2 45s when I get a chance. The only downside was I couldn't find an unequal Y joint so it has T joints for the drops. Not ideal but it works brilliantly with whatever drop in efficiency not causing a problem. I'm interested to hear what others think of the solution and hope no one is going to tell me the big reason it was all a bad idea!!View attachment 99627

Please excuse the mess! I am sorting through a bunch of stuff.

Forgive my ignorance, but what is the difference in diameter between this and the PVC soil pipe "solvent weld" system, and the off-the-shelf extract accessories such as blast gates?

 

[Walcote]

Forgive my ignorance, but what is the difference in diameter between this and the PVC soil pipe "solvent weld" system, and the off-the-shelf extract accessories such as blast gates?

I'm not totally sure. I think it is marginal but it is a little smaller and the Vent Duct is thinner wall so I don't think it is compatible without some kind of home made converter. I bought it all here:

TLC Direct 4" Vent Duct

It all came in at under £100. Including buying a load of extra connectors and angles for spare and some of which I butchered to reuse in the blast gates.

 

[Walcote]

I'm not totally sure. I think it is marginal but it is a little smaller and the Vent Duct is thinner wall so I don't think it is compatible without some kind of home made converter. I bought it all here:

TLC Direct 4" Vent Duct

It all came in at under £100. Including buying a load of extra connectors and angles for spare and some of which I butchered to reuse in the blast gates.

For reference, the actual ID of the 4" Duct I bought is approx. 98mm. I don't know what the Solvent Weld Soil Pipe is but I believe stated diameter is usually 110mm. They also sell a 5" and a 6" if you were to go for a bigger capacity system.

 

[Inspector]

Is there much consideration for 4" vent pipe? I recently made a system with 1 10m run and 3 drops and the 4" vent pipe was at least 50% cheaper than any other solution I looked at such as Soil Pipe and Galv. I was worried about static so have a bare copper wire running internally the length of the duct to ground and I have had no shock personally and no indication of static build up so far. It took a little more invention as there are not so many off the shelf dust extraction parts for it so I 3D printed and Laser cut gates and various fittings but they could easily have been done with basic woodworking skills. If anyone is interested, let me know and I'll post the 3D files online. I will be replacing the remaining 90 degree turn with 2 45s when I get a chance. The only downside was I couldn't find an unequal Y joint so it has T joints for the drops. Not ideal but it works brilliantly with whatever drop in efficiency not causing a problem. I'm interested to hear what others think of the solution and hope no one is going to tell me the big reason it was all a bad idea!!View attachment 99627

Please excuse the mess! I am sorting through a bunch of stuff.

I won't tell you you did wrong but going forward I will tell you your plan to change from the 90º to a pair of 45º fittings won't improve anything. As a 90º with what looks to be a 0.75R or smaller, you have an equivalent drag of 37'/11.28M of straight pipe. A 45 elbow has an equivalent of 20'/6.1M so making the turn with two is 40'/12.52M plus whatever straight piece between. Want to call it 41'/12.5M? That improvement is going backward. Now if you can find an elbow with a radius of 1.5R (maybe from one of the other types of pipe you can get even if it means a little cutting/grinding to make it fit) you will have a 17'/5.18M equivalent of straight pipe. Those numbers come from page 54 of http://www.lorencook.com/PDFs/Catalogs/Cookbook_Catalog.pdf

Taking the T fitting out and replacing with a couple 45º fitting will make a big improvement because the T has a straight duct equivalent of 125'/38.1M. That coming from 6A on page 61 on the link above. If you want a template calculator for cutting the pieces to make a 45º branch fitting. Pipe Joint Template Software

My metric equivalents are rounded up/down a bit.
Pete