Pushfit soil pipe as dust extraction

[Misterdog]

'Swept' elbows create less drag.

https://www.plastics-express.co.uk/...-87c2b0-single-socket-bend-28swept29-p-pte354

 

[Sandyn]

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.

In a DIY scenario, you aren't bringing anything on to the market i.e. you are not selling the system, I don't see it how any of the directives could be made to apply in law.
What do you think?

I was in IT equipment manufacturing certification, so different ways of injuring and killing people, I produced many bespoke systems which were sold.
There is scope within the directives to sell a product without approvals, if it is a prototype and if you don't produce many. The customer must obviously understand what they are buying. This wouldn't waive your requirement to make sure it's safe, so whilst you can, it exposes you to risk if something goes wrong. You could do a self certification, but that generally isn't worth the paper it's printed on, just box ticking,
I could see a few apparent ways round the legislation, but all of them expose the company to risk.

If all that fails, you just sell it on the internet from the far east!!

 

[NetBlindPaul]

In a DIY scenario, you aren't bringing anything on to the market i.e. you are not selling the system, I don't see it how any of the directives could be made to apply in law.
What do you think?

I was in IT equipment manufacturing certification, so different ways of injuring and killing people, I produced many bespoke systems which were sold.
There is scope within the directives to sell a product without approvals, if it is a prototype and if you don't produce many. The customer must obviously understand what they are buying. This wouldn't waive your requirement to make sure it's safe, so whilst you can, it exposes you to risk if something goes wrong. You could do a self certification, but that generally isn't worth the paper it's printed on, just box ticking,
I could see a few apparent ways round the legislation, but all of them expose the company to risk.

If all that fails, you just sell it on the internet from the far east!!

With respect to the MD, it specifically includes equipment designed and built for one's own use.
Now yes these pieces of legislation are aimed at businesses, but this is not defined in the legislation.

In the MD & LVD, there is no legitimate means for placing a device on the market if it is not compliant.
However, both of these are self-certification apart from certain safety devices, and LEV is borderline.
One could ignore the legislation and EHSR's and just put the CE mark on and sell it, the chances of getting caught are slim, and this would expose the company to risk.
However, any conscientious engineer or professional should never consider such if they have any sort of moral compass.

I don't believe that your last comment is serious surely?

 

[NetBlindPaul]

'Swept' elbows create less drag.

https://www.plastics-express.co.uk/...-87c2b0-single-socket-bend-28swept29-p-pte354

Absolutely!
The larger the bend radius the better, also, a 45 deg leg T is much better than a 90 deg T.
Straight seamed metal duct is better than spiral.
Solid duct is better than flexy.

 

[Misterdog]

Should we all fit our extractors within explosion proof cubicles, and also have spark arrestor systems?

To be fully compliant.

 

[gregmcateer]

Walcote,
Please don't apologise for the 'mess' - that is operating theatre clean and tidy !!

 

[Walcote]

Walcote,
Please don't apologise for the 'mess' - that is operating theatre clean and tidy !!

Haha. Thanks, It looks so much better and is nicer to use when tidy but it's definitely hard to keep it that way!

 

[BruceK]

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.

Great looking workshop. Hopefully mine will look like that soon. I'm currently making blast gates for a 110mm underground pvc system and plan to earth the pipes as you have yours. How are you heating your workshop?

 

[NetBlindPaul]

I do have a different view on LEV having done the BOHS LEV courses, and been involved in the aftermath of two LEV fires, one where I was called upon to remove the burned out system and check the machine over for damage. Luckily the fire was limited to the LEV filter assembly, but that was a full evacuation of the premises and two fire appliances. Yes it was commercial, but a very small joinery, admittedly with big machines.
The other I was called upon as an expert witness to review an LEV fire on a smll Record bandsaw with a dedicated LEV in a school, so very similar to a DIY setup. It was not possible to ascertain the root cause of the fire, and it did not destroy the LEV. Again this was a full evacuation of over 1000 pupils and a call to the local fire brigade, I think though it was 4 appliances as it was a school.
I can’t say too much as to the exact locations nor findings due to client and commercial confidentiality, but, I think this covers enough to get the gist.

 

[Walcote]

Great looking workshop. Hopefully mine will look like that soon. I'm currently making blast gates for a 110mm underground pvc system and plan to earth the pipes as you have yours. How are you heating your workshop?

Thanks it has taken quite a few years to get it that way but it's almost there... kind of! I was lucky to have bought a house with an annex with Air Conditioning already built in. There are two Mitsubishi Electric split AC systems in there. It is perfect for the workshop. Cool in summer, warm in winter and keeps the humidity in check. I'm not sure I would have splashed out in the first place had it not been there but if it is available to you I highly recommend it.

As for the blast gates, from making them, the thing I was most pleased with was fitting microswitches to each one. I ran them into a relay to switch the extraction on. This way it means the system is switched on at the tool and is on till the gate is shut. This makes me shut the gates each time which I forget a lot so there are not extra gates open unnecessarily.

 

[OldWood]

Having seen that Paul is of the opinion that insurance companies could well apply commercial legislation requirements to DIY extraction systems, where does that place the amateur using machinery from a bygone era. We all take care of ourselves as far as possible with guards and the likes but I am thinking of the bandsaw as an example where modern machines in the industrial world will have a brake to stop the blade quickly. The same will apply with many other machines where i understand dc injection into a 3 ph motor will stop it pretty quickly.

 

[NetBlindPaul]

Having seen that Paul is of the opinion that insurance companies could well apply commercial legislation requirements to DIY extraction systems, where does that place the amateur using machinery from a bygone era. We all take care of ourselves as far as possible with guards and the likes but I am thinking of the bandsaw as an example where modern machines in the industrial world will have a brake to stop the blade quickly. The same will apply with many other machines where i understand dc injection into a 3 ph motor will stop it pretty quickly.

I'm not "of the opinion" per se.
I am just highlighting the potential that should there be a claim on your house insurance policy the insurer would potentially be looking to appoint loss adjusters and expert witnesses to limit their financial exposure.
They might look to expect a similar level of safety for protection of their insured asset as would be expected in the legislation covering that product if it were procured from a supplier.
A DIY built system would not offer that level, especially if it used plastic pipework.

As far as injuries go, it would not involve the premises insurer, the treatment would be by the NHS and as it is DIY it is not RIDDOR reportable and thus would be looked upon as a folly more than likely.
Therefore no interest from HSE, nor the LA.

Two completely different sets of legislation and requirements for the LEV and injuring yourselves with old machinery, because you are building bespoke LEV after the SMSR has come into force.

As far as the machinery goes, the offence would be supplying a machine which does not comply, PUWER requires that all machinery must meet minimum safety standards. Any dealer is legally bound to ensure that any machinery they sell is compliant with PUWER, pending installation.
Even if this is to an individual (i.e. DIY buyer).
However, PUWER is definitely a workplace piece of legislation. It does not apply to home DIY use, so the buyer/user as long as they are not operating for remuneration would be in the clear.

 

[Walcote]

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

Thanks Pete. That is a great bit of information. The conventional wisdom seems to be 2x45º elbows are better than one 90º so this is useful to know with the added confirmation of source material. I will print some large radius bends and smooth Y shaped junctions when I next get a moment. The system appears to work well as it is but it is always good to add some extra oomph without resorting to increasing power! Comparing it to runs of straight pipe is a very easy way to relate to the information as well as a method to calculate the numbers. Cheers!

 

[NetBlindPaul]

Leaks in the runs are another way to loose lots of efficiency too, so make sure your joints are air tight.
Mind, you need to ensure also that you have enough air to hit the transport velocity to carry the waste all the way to the filter. Not such a problem if your duct is all the same size and you only use one machine, so only one gate open at a time, as long as you have the velocity at the most extreme point you should be fine.

 

[Walcote]

Leaks in the runs are another way to loose lots of efficiency too, so make sure your joints are air tight.
Mind, you need to ensure also that you have enough air to hit the transport velocity to carry the waste all the way to the filter. Not such a problem if your duct is all the same size and you only use one machine, so only one gate open at a time, as long as you have the velocity at the most extreme point you should be fine.

More good points. I learned the hard way with the velocity issue. I bought a load of flexible hose for cleanup but had to replace it all with a wider diameter to keep the air flowing. Same with the run into the belt sander.

 

[NetBlindPaul]

Try to keep flexy to a minimum. The losses are immense. I can’t recall the figures but it is something like 1m of flexy is the equivalent of 30m of longitudinally seamed steel. I am more than happy to be corrected if someone else has the exact figures.

I have limited resources stuck in my hospital bed!

 

[Sandyn]

With respect to the MD, it specifically includes equipment designed and built for one's own use.
Now yes these pieces of legislation are aimed at businesses, but this is not defined in the legislation.

In the MD & LVD, there is no legitimate means for placing a device on the market if it is not compliant.
However, both of these are self-certification apart from certain safety devices, and LEV is borderline.
One could ignore the legislation and EHSR's and just put the CE mark on and sell it, the chances of getting caught are slim, and this would expose the company to risk.
However, any conscientious engineer or professional should never consider such if they have any sort of moral compass.

I don't believe that your last comment is serious surely?

I'm not familiar with the MD, perhaps there is a similar clause for IT equipment, but I missed it. They are such convoluted documents. That is quite significant to include home built equipment.
When it comes to making money, there seems to be no moral compass in some cases. I have been in a company and discovered a plastic part had been moulded with the wrong material. I informed management, but was completely overruled about informing customers who had already purchased the product. I wanted to do a recall/replacement of the bad part. It led to huge arguments and me being classed as a troublemaker. In the end I was cut off all communication/meetings, My conscience was clear, so left them to it. Just a crap company.

No, my last statement was not serious, I was being sarcastic, A lot of the stuff I have received from a big online retailer has come from the Far East. It either has no CE marking, or it's illegally CE marked, or had what I call a Far East 'certification'. The online retailers refuse to take responsibility and you have absolutely no chance of finding the manufacturer should something go wrong, so that's the way to sell non certified products.

In your experience....do you think far eastern supplied (unbadged) machinery has had the proper certification done on it?

Hope you are doing well

 

[NetBlindPaul]

Some of the Far Eastern machinery is done correctly but not a lot of it.
We do work with some Japanese companies that are trying to get it right, but they simply don’t understand the requirements.
I have worked with one Chinese company who really wanted to get things right again they didn’t understand the requirements and I struggled to get them to. In the end it fell down because they were unwilling to allow any technical information to leave the company. Thus they could not have the technical file held in Europe.

 

[Inspector]

Try to keep flexy to a minimum. The losses are immense. I can’t recall the figures but it is something like 1m of flexy is the equivalent of 30m of longitudinally seamed steel. I am more than happy to be corrected if someone else has the exact figures.

I have limited resources stuck in my hospital bed!

Happy New Year Paul.
The losses approach to 3 to 1 as a rule of thumb. The closest to exact figures that come to mind at the moment is this online duct friction loss calculator. On-Line Duct Friction Loss You can play with different sizes and lengths of ducts and materials to get the static pressure loss in inches of water. It doesn't have the metric option you would be more likely to have worked with but I'm pretty sure you can figure it out. Once you get a result you can go back and change it to a different duct material to see how much of a change there is. I suppose in a mixed material system one would figure out the different areas and add the results together for a total.

When one realizes a small DC only has 5 or 6 inches of static pressure with no flow and only a couple when wide open it shows why many small shops have so much dust everywhere.
Pete

 

[NetBlindPaul]

Happy New Year Paul.
The losses approach to 3 to 1 as a rule of thumb. The closest to exact figures that come to mind at the moment is this online duct friction loss calculator. On-Line Duct Friction Loss You can play with different sizes and lengths of ducts and materials to get the static pressure loss in inches of water. It doesn't have the metric option you would be more likely to have worked with but I'm pretty sure you can figure it out. Once you get a result you can go back and change it to a different duct material to see how much of a change there is. I suppose in a mixed material system one would figure out the different areas and add the results together for a total.

When one realizes a small DC only has 5 or 6 inches of static pressure with no flow and only a couple when wide open it shows why many small shops have so much dust everywhere.
Pete

Yes the procedure is to calculate the individual losses for the linear sections by material and the individual bends and fittings and any flexy, then add them to get the total lossess.