Pushfit soil pipe as dust extraction

[Terrytpot]

to be honest I was quite surprised at how cheap the galv spiral ducting is .. screwfix sell 110.. soil @ £15.89 3m whereas Dustspares sell 125 spiral @ £15.96 3m. or 100mm @ £13.20 3m. I'm not quite ready to install ducting myself but think when I am I know which way I'll be leaning

 

[Mike Jordan]

Terrytpot you have it sorted ! I am amazed that fellow woodworkers will invent excuses and go to lots of trouble to convince themselves that materials designed for drainage are safe and better than the proper ducting. It all joins up easily and has no static problems or need for suspect earthing methods
It's fire resistant and matches industry standards. It will be interesting to see if your sensible approach leads to you being accused of smoking wacky bacy as I was a few posts back.

 

[dzj]

PVC works well, but at those prices, you might as well do it properly.
Most important thing is to keep your shop clean. Spark or no spark, you can't have a fire if there's nothing to ignite.

 

[Mike Jordan]

Axi sell plastic fittings for use with drainpipe systems. From what little I've seen they are more expensive than the metal versions.

 

[DBT85]

Terrytpot you have it sorted ! I am amazed that fellow woodworkers will invent excuses and go to lots of trouble to convince themselves that materials designed for drainage are safe and better than the proper ducting. It all joins up easily and has no static problems or need for suspect earthing methods
It's fire resistant and matches industry standards. It will be interesting to see if your sensible approach leads to you being accused of smoking wacky bacy as I was a few posts back.

Which posts were these?

 

[Mike Jordan]

It was MikeK in an early post. In fairness I did Imply that he was a little gullible. It turns out that his shop is in an area where metal ducting is grossly overpriced.

 

[Retired]

Hi,

I was trained down a deep coal mine; if you want to mix combustible dust with static then expect the worst; it's too late when there's an explosion. Why kick this dangerous subject around on a forum in front of the world; a phone call to your local fire service should be the first point of contact. I was in charge of the timber department at work and would never use plastic for woodworking machinery extraction.

Check with your home insurance company who would most likely reject an insurance claim.

Kind regards, Colin.

 

[TRITON]

+1
For a 90 translation use two 45 degree bends or a so called "slow bend" from the underground range. Glue in 100mm plastic blast gates into pipe ends with foaming pu glue and the other side fits 100mm flexi to the machine perfectly.
Ignore anyone who tells you there is a static problem.

I'd use gaffa or duct tape rather than glue as its easier to reconfigure shold he wish to.

 

[Mike Jordan]

Retired, you are right and have the knowledge! The phone call you suggest would have been ringing out on my desk a couple of decades back.
I've tackled fires in dusts and actually caused them In controlled circumstances. The insurance problem has also been mentioned before.
It seems that nothing will convince the plastic pipe champions!
I have a friend who's system runs underground from his workshop ( where the pipes are metal) to discharge in a shed in the back garden, that's the only piece of safe plastic ducting I know of.

 

[gregmcateer]

I have no axe to grind either way, just an interest in learning more.
So - if plastic pipe is that dangerous,
a) why is it permitted by HSE?
And
b) why do pretty much all wood cutting and shaping machinery manufacturers and DE machines supply them with at least some length of plastic pipe?

Genuine question, btw

 

[Mike Jordan]

As you say, most systems, including mine,have short lengths of flexible plastic pipe connecting machines to the metal ducting. This is kept to a minimum and is of course earthed through the machine and the metal pipes. It does however generate some static, this can be seen in the fact that small chippings tend o stick to the outside of the pipe when the system is new.
The effect seems to stop when the pipes get a bit grubby.
The flexi pipe is usually made with a wire spiral bonded into it.
Let's be clear, the chances of a dust explosion in a small system must be very small, but it's one that is largely eliminated by the use of the proper ducting which is the same price, or even cheaper, than plastic.
Explosions in dust can be very violent and destructive, as Retired mentioned coal mines take great care to avoid /suppress any occurrence since many lives are at risk. If you want to see evidence of problems try googling fires in paper or pulp mills.

 

[Retired]

Hi,

I agree with you entirely Mike Jordan.

Spark Arrestor Manufacturers | Spark Arrestor Suppliers

Before retiring I was registered with the HSE because of my responsibilities being in charge of the timber department at work. Having been safety trained down a deep coal mine I know only too well the risk of explosion; yes the risk is small in say a home workshop but what if the explosion should happen in your own workshop; it would then bring the risk home to you but then of course it always happens to someone else.

I used to receive up to date information from the HSE

HSE Woodnig Newsletters

I and a colleague used to visit a large demonstration once each year of all modern woodworking equipment; one demonstration showed spark arrestors these really demonstrating how easy it was to cause a fire/explosion this in steel ducting so nothing is 100% safe.

TIMCON - The Timber Packaging and Pallet Confederation

There's so much legislation around these days it's surprising anything gets done here in the UK. I thought it was complicated enough over 20 years ago keeping up to date but now it's an whole lot worse. I was also in charge of two more departments and the responsibility weighed heavily on me as well as the huge amount of stress of the normal job keeping everything running smoothly.

It's no longer being accountable of your own mistakes or actions but anyone in management right up to the very top could well end up in court in serious trouble should an employee be involved in an accident even though management weren't present at the time.

I'm very careful as to replies I post on open forums because should I encourage anyone to adopt an unsafe practice it could come back to me as in this thread; if I said it's fine to use plastic ducting in extraction and a member took me at my word then suffering an explosion quoting me saying I'd encouraged the use of plastic ducting I'd be very exposed indeed because I know I'm completely unqualified to offer such advice.

What does surprise me is that so many would think nothing of spending a lot of money on the latest must have electronic gadget which would be out of date in a month or pay to watch someone kick a ball around a field but would begrudge paying for personal safety?

I DON'T RECOMMEND THE USE OF PLASTIC DUCTING AS BEING DESCRIBED IN THIS THREAD.

Kind regards, Colin.

 

[Sandyn]

I have no axe to grind either way, just an interest in learning more.
So - if plastic pipe is that dangerous,
a) why is it permitted by HSE?
And
b) why do pretty much all wood cutting and shaping machinery manufacturers and DE machines supply them with at least some length of plastic pipe?

Genuine question, btw

When trying to get to the bottom of this question, I did find this It seems to suggest that HSE recognise the risk of plastic ducting, and recommend the following.

"""Make ductwork as short as possible with a minimum number of bends. The design should specify a minimum transport (or conveying) velocity3 of 20 m/s to minimise dust deposits. Use only conductive materials for ductwork so that any static electricity generated can be discharged to earth. """

EDIT:- I don't follow HSE advice at home (on just about everything) , but if it was work related, it would be a different matter.

 

[Mike Jordan]

That's a clear and sensible statement Colin.
I've wondered throughout this thread if axi and other suppliers of plastic parts which are intended for use with drainpipe would find themselves in the firing line if the worse happened.
I have some concern about those who advocate the use of pallet wood for use in woodworking. My knowledge is limited but I believe that a lot of it is treated with chemicals which means that it shouldn't even be burnt let alone inhaled as dust.

 

[gregmcateer]

Colin, Mike, Sandyn,
Thank you for your input and clear, helpful explanations.
Cheers
Greg

 

[Retired]

Hi,

Thanks Mike Jordan; yes it pays to be very careful using any second hand timber;

"Why are blue pallets illegal?
This stands for Methyl Bromide which is a harmful chemical used to prevent wood eating insects consuming the pallets. It was banned in the UK 5 years ago so they are much rarer to come by now.1 Jul 2015

We made thousands of pallets and packing crates etc. we also bought in loads of 300 at a time second hand Euro pallets. Occasionally blue pallets would turn up and I was aware of the problems associated with reusing "Chep" pallets so these were not reused by us. I'm out of touch with all modern safety laws having retired 20 years ago. Yes lots of timber is harmful to an unsuspecting user; treated timber for exterior use gives off toxic fumes when burned but few will be aware of this; I'm unsure if this is still the case. Exotic timbers used by woodturners can cause serious health problems.

We never used treated timber for making pallets just buying 3 cube loads at a time of sawn softwood.

Broken pallets were always a problem for me to dispose of at work; one of my team members lived on a council estate in Barnsley and he had a neighbour who was retired and kindly cut up firewood for other neighbours; he wasn't a driver but to get rid of broken pallets I often authorized a team member who could drive to borrow the works pick up truck hence everyone was happy. One day the team member asked for more pallets so I asked him how many his neighbour could cope with "as many as you have" I despatched a 40' curtain sided trailer; the load of broken pallets filled three front gardens; I did at the time knowing where he lived asked if his neighbours were using the pallets as double glazing?

Obviously in the timber department we had lots of saw dust and shavings; one of the team had hamsters and I refused to let him take sawdust; I just didn't have the time to stand and explain so he left in a huff; later in the day I asked him if he wanted to kill his hamsters; we'd been running a lot of hardwood through the saws.

Sorry to divert this thread off topic but whomever pays the money has the choice as to type of ducting they use for dust extraction; it's easy to knock H&S guidelines but they are there for everyone's safety.

Kind regards, Colin.

 

[TRITON]

The flexi pipe is usually made with a wire spiral bonded into it.

Yeah but its not connected to anything. And certainly not to earth. The wire is encaptulated totally so even at each connected side- which is plastic incidentally, the wire doesn't touch any metal part of machine or extractor.

 

[NetBlindPaul]

The wire is intended to be exposed at the end where it mates to the metallic duct and be connected to said metallic duct.
BS 7671 requires that the metallic duct in most cases is connected to the orotectice conductor network of the electrical installation and is thus connected to earth via this path.
Building regulations require compliance with Part P of the building regulations, which require compliance with BS 7671.
Plastic pipe work such as 110mm soil pipe etc. is not safe, nor suitable for use for extraction.
Whilst your home insurer will probably not be interested in any harm you bring on yourself whilst undertaking yiur hobby.
The small print of your policy may well require compliance with BS7671, and mat well consider the use of plastc ductwork for the conveyance of dust, which is a well known and documented explosion and fire risk, would also invalidate qny claim you may make.
In any business undertaking, compliance with the law is required, and realistically, this would preclude the use of plastic duct.

 

[Inspector]

Paul I don't doubt for a second your qualifications. You said "is a well known and documented explosion and fire risk". I've seen that written many times over the years but have never seen any actual reports from home shops. Factories and sawmills for sure but never a home shop static explosion/fire. I'll happily sit corrected if there are any.

Pete

 

[MikeK]

Paul I don't doubt for a second your qualifications. You said "is a well known and documented explosion and fire risk". I've seen that written many times over the years but have never seen any actual reports from home shops. Factories and sawmills for sure but never a home shop static explosion/fire. I'll happily sit corrected if there are any.

Pete

Pete,

I'm with you on this. I searched for years to find just one documented case where a hobbyist woodshop experienced an explosion or fire directly attributed to static buildup in the PVC ducting. Given the widespread use of non-metallic ducting throughout Austraila, North America, and Europe in basement, shed, and garage shops, I would expect at least one report of a static-induced explosion to support the claims; however, I have never found any.