Australian Boiler Code

[Blue Peter]

Hi
Is there anywhere in the UK that sells the Australian Boiler Code for Copper boilers or do I have to buy it from somewher in Australia?
Regards
Peter

[steam4ian]

G'day Peter

With the pound to AUD exchange rate I am not surprised at your question.

"Australian Model Engineer" sells the codes and other books and provide a reliable service, postage is not expensive. I have bought the codes and other books from them and found then very good. The biggest delay in the delivery will be the UK postal service, Australia Post nowadays is very efficient.

Not exactly the answer you wanted but it may be the way you have to go.

Regards
Ian

[Blue Peter]

G'day Ian
Thanks for such a prompt reply. Just thought it might be easier but can't find anybody in UK advertizing online. Will go the route you suggest and have sent E-Mail to them.
Regards
Peter

[AndrewP]

Peter,
I got my copy online from here, really good read.

Andy

[Blue Peter]

Hello,
Thanks for the advice, got my copies from SMEX, dearer than AME but I could only use Paypal. Very interesting reading. it doesn't give design calculation formulae, but tables so there is nothing to work out. One surprise to me though was that I could use 2.5mm copper for a 6" dia boiler at 100psi. I had previously calculated this to need 3mm according to Martin Evans formula. K N Harriss in Model Boilers and Boilermaking uses 25,000psi as the strength of copper but reduces it to 95% for a butt strap joint and it works out to 2.5mm whereas Martin Evans in The Model Steam Locomotive ignores this but reduces it to 80% for a reduction in strength due to high temperature which means a 3mm thick shell. My question is, What design calculations where used when formulating the Australian code?
Regards
Peter

[steam4ian]

G'day Peter

Firstly Table 3.3.2 in the code supports your comment.

Looking up copper tube handbook I found the following:
For 152mm diameter the safe working pressure is 1300kPa at under 50 degC. the tensile stress at this temperature is 41MPa.
At 150-175 degC(for 100 psi/700kPa) the tensile stress is 28Mpa. Calculating back finds the safe working pressure at under 175 degC is 888kPa. This tube has a nominal wall thickness of 2.64mm with a minimum thickness 2.38mm.

All is well.

Regards
Ian

[Blue Peter]

Hello Ian
Thank you for your input. So 2.5mm thick copper sheet is fine for 153mm boiler at 700 Pascals, the code also allows all flanged plates to be 2.5mm as well.
Martin Evans states that all end plates should be 50% thicker than shells, but if you look at his Springbok boiler, the shell is mainly 3mm wall tube with 3mm sheet firebox wrapper. The smokebox tubeplate is 4mm thick, firebox tubeplate and backhead 3mm thick and the firebox backplate 2.5mm! What a contradiction.
Looking at Don Young's K1 boiler he uses 3mm wall tube with 3mm end plates and 2.5mm firebox and outer wrapper.
Other designs for similar boilers use 3mm sheet throughout, which is what I thought I would use for my first two boilers, but 2.5mm would be more economical.
I am making a Thompson B1 to scale dimensions, my first choice of a Springbok was abandoned when I realized the dimensions are all over the place. Then a Peppercorn K1 as the tender, cylinders and boiler are the same. The K1 boiler is just a bit shorter than the B1 as in full size. Both boilers should have a sloping backhead. I will draw up the boilers using 2.5mm copper sheet throughout and find a boiler inspector before starting work.
We shall see if 2.5mm is acceptable or whether 3mm will be demanded, which is why I wanted design calculations to prove the design.
Thanks again and kindest regards
Peter

[baggo]

I think the advice to make backheads, front tubeplates, etc. thicker than the wrappers and barrel is a legacy of the early LBSC days when fittings used to be screwed directly into the copper without using bushes. The thicker plates obviously gave deeper threads. With bushes, the extra thickness is not really necessary so long as the surfaces are adequately stayed. Might be worthwhile on the firebox tubeplate which gets scoured by grit and ash.

I've posted this link before but there is a useful spreadsheet to download here that does a lot of the work for you:

calslivesteam.org/calculations/Calculations.htm

John

[ausdan]

is 2.5mm readily available anyway? I need to replace and build for the 1st time a copper boiler for my 5"Don Young Hunslet
3mm is off the shelf product I can get easily from a local trade distributor
full sheet 900mm*1800mm @ $770AUD (+10%gst)... This is in Adelaide/Australia just for a comparison.

[steam4ian]

G'day Dan

Why don't you use tube?

A 5" Hunslet will not have a boiler diameter larger than commercially available tube. Both Ernie and Wayne are adverstising 5" tube.
Both are advertising either Sweet Pea or Blowfly boiler mateial kits for under $1000.

Regards
Ian

[Blue Peter]

Hi Baggo
Yes I have already got that spreadsheet from when you posted it before. This shows that a 6" dia boiler with 0.098" (2.5mm) shell at 100psi is safe to 104 psi but with a safety factor of only 5. Although it says this at 350degrees. If I put in 0.118" (3mm) it gives 125psi with a safety factor of 6. This is confusing me more as I thought the safety factor should be 8.
The questions going through my mind at the moment are:-
What deems the factor of safety to be 8?
Why do we use the shear strength and not the yield strength of copper?
What temperature does a boiler actually get to in service which would determine the reduction in strength of the copper?

As regards availability and price I got a quote for 2000 x 1000 x 3mm C106 copper sheet at £495 plus VAT and carriage from Metal Sheets in Liverpool, they also list 2.5mm.

Just looking at some other boiler designs I have found, they use either 3mm sheet throughout or outer shell and plates 3mm with firebox wrapper and plates 2.5mm. Their is obviously a difference of opinion from different designers. Thinking about the scouring effect of the flue gases then surely the firebox should have thicker sheet than the outer shell to make it last longer.

Regards to all who commented
Peter

[ausdan]

I can see ya point there Ian,
Would rather tube if it was cost effective and easy to get, nothing in Adelaide (except under somebody's bench I bet)

Last I checked buying almost anything of Ernie or ME supplies I found about 2-4 times more expensive than sourcing it myself.

ME supplie have advertised 5" by 14g at $9.1 a cm(is that 1.9mm ? I'm planning on 3mm, code is 2.5mm minimum), i think I'm need about 45cm thats $409 just for the barrel no shipping, compared to $90 if I use plate and a butt strap 30min down the rd...(the next thickness size up in the 6" Dia and above is $15 per cm. that would be around $600)

the full sheet will do all the Hunslet and 7.25 Phamton, plus left over...But Im still looking around for the best option, need to get started would be the best decision ;D

[taff]

Hello Peterhopkinson and all.
I have designed and cnstructed numerous copper boilers mainly for 5" gauge but some also larger and smaller gauges and I can also say hat I have experienced a vertical boiler exploding in my face. My feet didn't touch the ground I asure you. In my very early years I was given a copy of the Australian code of practice and I can say that for the passed fifty years I have designed and constructed all of my boilers to comply with this code. I have recently received updated copy's of the code and I can only express the opinion that it is brilliant and anybody who follows this code and advice both in designing and constructing model boilers will not go wrong at any stage. It has always been a matter of disapointment to me that our own British Federations have not produced a similar code or even adopted the Australian code for British use. I hope to see such and event in the future but in the meantime I will continue to refer to the Australian Code. Out Australian brothers are to be very much admired and congratulated for this contribution to our hobby.