90 degree bends in LPG rigid copper pipe

[ditchcrawler]

 

 

I don't actually know but I could speculate and dream up whole sheafs of possible reasons. That's all it would be though. Speculation.

 

I think the truth lies in what someone wrote in another thread earlier today:

 

Ok so first of all on the regulations, one can argue that this particular bit of this regulation isn't necessary in this particular circumstance, but that is what is generally called "re-inventing the wheel". There is a danger that a factor is overlooked and so it is better and simpler and usually not difficult just to go along with the regulation.

Wise words, don'tcher think?

Greeny

[MtB]

Greeny

 

 

Fanx!

 

(Is it a greenie because they are wise words, or because I was actually quoting Nick himself, in answer to his question?! )

[Alan de Enfield]

 

 

Fanx!

 

(Is it a greenie because they are wise words, or because I was actually quoting Nick himself, in answer to his question?! )

 

You now have another one - you can allocate them however you feel appropriate.

[ditchcrawler]

 

 

Fanx!

 

(Is it a greenie because they are wise words, or because I was actually quoting Nick himself, in answer to his question?! )

YES

[Radiomariner]

 

 

I don't actually know but I could speculate and dream up whole sheafs of possible reasons. That's all it would be though. Speculation.

 

I think the truth lies in what someone wrote in another thread earlier today:

 

Ok so first of all on the regulations, one can argue that this particular bit of this regulation isn't necessary in this particular circumstance, but that is what is generally called "re-inventing the wheel". There is a danger that a factor is overlooked and so it is better and simpler and usually not difficult just to go along with the regulation.

Wise words, don'tcher think?

Agreed. I think it is a case of "This standard is acceptable for this purpose" case closed. Other products may be to equal or even much better standard, but not, and probably never will, be tested to that particular standard. Got a bollocking once for replacing some transistors with ones of equal characteristics but of slightly power rating on some safety equipment.

[Radiomariner]

Agreed. I think it is a case of "This standard is acceptable for this purpose" case closed. Other products may be to equal or even much better standard, but not, and probably never will, be tested to that particular standard. Got a bollocking once for replacing some transistors with ones of equal characteristics but of slightly power rating on some safety equipment.

Whatever has happened to the edit facility? Wanted to change the above to read "...to a slightly higher rating, on..."

[bizzard]

I think that by using the thin walled copper tubing (8 and 10mm) for gas is that you can't tighten compression fittings satisfyingly tight, ''not over tightening of course'' the nut squashes the olive progressively squeezes the tube like a python and narrow waists it and is liable to leak. The thick wall tube doesn't do this and the nuts squeeze the olive just enough and stop, satisfyingly tight. '' know wot I mean Arry''.

Edited April 13, 2016 by bizzard

[BMC problems]

I think that by using the thin walled copper tubing (8 and 10mm) for gas is that you can't tighten compression fittings satisfyingly tight, ''not over tightening of course'' the nut squashes the olive progressively squeezes the tube like a python and narrow waists it and is liable to leak. The thick wall tube doesn't do this and the nuts squeeze the olive just enough and stop, satisfyingly tight. '' know wot I mean Arry''.

 

To this I can only say "inserts, dear chap, inserts"

[smileypete]

 

To this I can only say "inserts, dear chap, inserts"

 

Not easy to find for metric copper tube though, BES do one size and the matching pipe is almost thick enough to comply. Maybe intended for domestic oil installations.

 

A good source of imperial copper tube, which may excees the thickness requirement, is soft copper tube used for air conditioning.

 

There's also stainless flexi tube, bet it gets used on some large lumpy water boats though overkill for a narrowboat.

 

Trouble with many regs is they only specify the solution, not the problem, so over time can become less relevant and preclude better ways of addressing the original problem.

 

cheers, Pete.

~smpt~

Edited April 13, 2016 by smileypete

[Radiomariner]

I think that by using the thin walled copper tubing (8 and 10mm) for gas is that you can't tighten compression fittings satisfyingly tight, ''not over tightening of course'' the nut squashes the olive progressively squeezes the tube like a python and narrow waists it and is liable to leak. The thick wall tube doesn't do this and the nuts squeeze the olive just enough and stop, satisfyingly tight. '' know wot I mean Arry''.

 

 

 

To this I can only say "inserts, dear chap, inserts"

Using copper rather than brass olives helps. If you can get them inserts would certainly help. Bizzard comments that the olive squeezes the tube: Having examined quite a number of failed compression couplings it appears as if the tube gets stretched (thinner) rather than squeezed.

[steamcompound]

Are silver soldered nipples allowed on gas systems? "olives" on steam systems are not liked because the pipe has a tendency to blow out if the pipe nut is not is not tightened to a "crush pipe" state after which it is no use at all the second time (slight exaggeration, not) the thing has been taken down and put back.

[mboatyboat]

On 4/12/2016 at 22:53, Mike the Boilerman said:

 

Yes it does, if the installation is to comply with PD 5482-2005 part 3.

 

If you don't care about complying with that (it's only mandatory for RCD) then a BSS bod probably won't be bothered as I don't think wall thickness is mandated in the BSS.

 

Whether thick walling is a Good Idea technically is a whole nother discussion!

 

 

 

 

(Edit to remove the spurious word.)

I've been trawling through all the regs around LPG. I've had a look through PD 5482-2005 part 3 (via Manchester online library) and it doesn't specify a wall thickness in that document. However, the BS EN ISO 10239 document does state a minimum wall thickness. The 2008 versions of this standard required a wall thickness of 0.8mm but the document was revised in 2014 and now states that a 0.6mm thickness is acceptable (up to an OD of 12mm). AFAIK this means that standard 10mm microbore from screwfix is acceptable.

This point has come up on canalworld before now, but google searches seem to return the older posts stating that we must use the thicker imperial copper to comply with the standards. Please correct me if i'm wrong.

 

Edited July 14, 2017 by mboatyboat
clarification

[Alan de Enfield]

2 minutes ago, mboatyboat said:

AFAIK this means that standard 10mm microbore from screwfix is acceptable.

It may be acceptable, but, being so small will it give the volume required by all your appliances 'all on at the same time' ?

 

[mboatyboat]

10 minutes ago, Alan de Enfield said:

It may be acceptable, but, being so small will it give the volume required by all your appliances 'all on at the same time' ?

 

Hi Alun, thanks for the question. I estimated an 8kW peak consumption (from a two ring burner and a gas grill + oven), using Table3 in PD 5482-2:2005 I calculated a pressure drop of 1.77mbar (max pressure drop they state is 2.5mbar).

[mross]

Another advantage of thick walled pipe is that it won't chafe through so quickly if the pipe rubs against something - which it won't if properly supported.

[Alan de Enfield]

16 minutes ago, mboatyboat said:

Hi Alun, thanks for the question. I estimated an 8kW peak consumption (from a two ring burner and a gas grill + oven), using Table3 in PD 5482-2:2005 I calculated a pressure drop of 1.77mbar (max pressure drop they state is 2.5mbar).

So, you should be fine with your 'small demand'.

[mross]

On 4/14/2016 at 19:52, steamcompound said:

 

Are silver soldered nipples allowed on gas systems?

 

No, per BSS, all connections on copper pipe must be compression fittings.

7.8.3 Are all LPG pipe joints accessible for inspection and of the correct type?

All LPG pipe joints must be accessible for inspection. All LPG pipe joints must be compression fittings on copper pipework

[MtB]

On 14/07/2017 at 11:40, mross said:

No, per BSS, all connections on copper pipe must be compression fittings.

7.8.3 Are all LPG pipe joints accessible for inspection and of the correct type?

All LPG pipe joints must be accessible for inspection. All LPG pipe joints must be compression fittings on copper pipework

 

Curious. PD5482-2005 part 3 allows brazed joints and screwed stainless steel pipe systems too, IIRC. I doubt PD54823 says otherwise although I admit I haven't read it.

[Chewbacka]

16 minutes ago, mross said:

No, per BSS, all connections on copper pipe must be compression fittings.

7.8.3 Are all LPG pipe joints accessible for inspection and of the correct type?

All LPG pipe joints must be accessible for inspection. All LPG pipe joints must be compression fittings on copper pipework

From memory the ISO std applicable to the RCD does allow hard soldered joints (this is from memory) however mross is correct in that the BSS does not, maybe they will update the BSS, but then again maybe they will not.

It is inteseting that the cross sectional area of 10mm pipe with 0.6mm wall thickness is 60.8mm2 where as a 10.mm pipe with 0.8mm is 55mm2, so about 10% larger cross sectional area.

As to buying microbore from screwfix, the BSS examiner is unable to see what wall thickness the pipe is or if it is correctly annealed, so in that regard it would not fail the BSS, but that does not make it safe.  The ISO standard does require you to use correctly annealed pipe, so you must buy pipe suitable for LPG.  If you do use the thin wall section pipe, you can get pipe inserts to support the pipe in the compression joint.

Added - Some imperial pipe is also now thin wall, so just buying an imperial pipe no longer guarantees you will get the thicker walled stuff.  As bubble testers and cookers tend to be supplied with metric fittings, and compression fittings suitable for LPG are easily available in metric, if fitting out a boat today I see no advantage in using imperial pipe and fittings.

Edited July 14, 2017 by Chewbacka

[MtB]

On 14/07/2017 at 11:55, Chewbacka said:

From memory the ISO std applicable to the RCD does allow hard soldered joints (this is from memory) however mross is correct in that the BSS does not, maybe they will update the BSS, but then again maybe they will not.

It is inteseting that the cross sectional area of 10mm pipe with 0.6mm wall thickness is 60.8mm2 where as a 10.mm pipe with 0.8mm is 55mm2, so about 10% larger cross sectional area.

As to buying microbore from screwfix, the BSS examiner is unable to see what wall thickness the pipe is or if it is correctly annealed, so in that regard it would not fail the BSS, but that does not make it safe.  The ISO standard does require you to use correctly annealed pipe, so you must buy pipe suitable for LPG.  If you do use the thin wall section pipe, you can get pipe inserts to support the pipe in the compression joint.

 

Point of order...

I think the BS to which the pipe is manufactured has to be printed on the outside of the pipe, so inspectors can read it. No printed spec, the pipe doesn't comply, QED.

[Chewbacka]

2 minutes ago, Mike the Boilerman said:

 

Point of order...

I think the BS to which the pipe is manufactured has to be printed on the outside of the pipe, so inspectors can read it. No printed spec, the pipe doesn't comply, QED.

Maybe, but the BSS only specifies that LPG hose is marked and compliant, copper pipe is not checked for marking or specification, so unmarked pipe is not as far as I can see a BSS fail.

[BEngo]

Oddly enough, gas pipe thickness is one area where the BSS actually sought some engineering analysis. Way back in the Allison days there was a lot of potentially non-compliant systems if BS 5482Pt3 or the then version of PD 5482 were the yardstick for pipework.  There was also the proplem of how inexpert examiners could actually check what sort of pipe had been installed without dismantling or other disruptive testing.

BSS office actually had the safe working pressure of assorted half-hard  and annealed pipes worked out.  In all cases this was way above the bottle pressure for either Butane or Propane so even a regulator runaway up was not going to cause a pipe failure. The Technical Committee thereupon agreed not to worry about having 'proper' gas pipe as there did not appear to be any problem with other sorts of pipe provided the material was OK.

OT Most car brake pipes in the days MtB recalls were steel- hence their propensity to rust and fail the MOT. Posh cars had tungum, which does not rust.