- Thread starter steamer
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Doesn't really matter what the use of the boiler is for, although I assume some kind of steam driven model train or such? Boiler will have to be welded to asme, more so if to be used at fetes and the like, especially with Joe public riding on steam driven equipment, certification fit for purpose will be required.
If solely for your own use, you may get away with hydraulic testing of said boiler, but how many bar, for how many minutes/hours?
I'm sure others will fill in with further advice.
Cheers........
If solely for your own use, you may get away with hydraulic testing of said boiler, but how many bar, for how many minutes/hours?
I'm sure others will fill in with further advice.
Cheers........
rikrobson
Member
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From a model steam forum.
The following changes to the ‘Examination And Testing of Miniature Steam Boilers’
code of practice (Spring 2007) have now been agreed and accepted by leading
insurers in the UK.
Small boilers (i.e boilers with a capacity of not more than 3.0 bar/litres)
are exempted from the requirements of this code. However, it
is recommended that small boilers be fitted with, at least, a safety
valve and a pressure gauge and that these be tested every 12 months
in order to ensure correct operation at the correct release pressure.
The boiler and the pipework installation should
also be checked at least every 12 months.
This is good news for the majority of you, since it doubles the original exemption
figure of 1.5 bar/ litre capacity, and is the biggest change from a model boating point
of view. Basically it now means that at least 85% of our model boat boilers are now
exempt from the requirements of the new code….i.e they DO NOT need to be
Tested.
A telephone call, made to the notifying body/publishers of these new rules, confirmed
that ‘EXEMPT’ also includes the steam test requirements.
Having said this, they then highlighted/emphasised the recommendation made in the
statement above, and I must agree that they should be implemented by everyone, for
your own safety, as well as that of other bystanders….in actual fact I am surprised
that these were not made MANDATORY.
The following changes to the ‘Examination And Testing of Miniature Steam Boilers’
code of practice (Spring 2007) have now been agreed and accepted by leading
insurers in the UK.
Small boilers (i.e boilers with a capacity of not more than 3.0 bar/litres)
are exempted from the requirements of this code. However, it
is recommended that small boilers be fitted with, at least, a safety
valve and a pressure gauge and that these be tested every 12 months
in order to ensure correct operation at the correct release pressure.
The boiler and the pipework installation should
also be checked at least every 12 months.
This is good news for the majority of you, since it doubles the original exemption
figure of 1.5 bar/ litre capacity, and is the biggest change from a model boating point
of view. Basically it now means that at least 85% of our model boat boilers are now
exempt from the requirements of the new code….i.e they DO NOT need to be
Tested.
A telephone call, made to the notifying body/publishers of these new rules, confirmed
that ‘EXEMPT’ also includes the steam test requirements.
Having said this, they then highlighted/emphasised the recommendation made in the
statement above, and I must agree that they should be implemented by everyone, for
your own safety, as well as that of other bystanders….in actual fact I am surprised
that these were not made MANDATORY.
Drains
Yeah, nah.
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You'd think that the pressure would be the same regardless of the volume...
3Bar = 43.5 psi.. Which isn't much in a well designed and made vessel. I'd have thought a hydraulic test would be sensible, as well as a properly working safety valve. ASME wps and certs might be overdoing it a little.
"Real" Steam railway locos might be generating in the region of 200-250 psi. Definitely a case for doing it properly!
3Bar = 43.5 psi.. Which isn't much in a well designed and made vessel. I'd have thought a hydraulic test would be sensible, as well as a properly working safety valve. ASME wps and certs might be overdoing it a little.
"Real" Steam railway locos might be generating in the region of 200-250 psi. Definitely a case for doing it properly!
rtbcomp
Moderator
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More volume = more surface area = more force for a given pressure.
Hmm. Given that pressure is, by definition, measured per unit area I don't think that's exactly true, though I know what you're saying.
malcolm
& Clementine the Cat
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Re-read maybe ArchieHmm. Given that pressure is, by definition, measured per unit area I don't think that's exactly true, though I know what you're saying.
rtbcomp
Moderator
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Hmm. Given that pressure is, by definition, measured per unit area I don't think that's exactly true, though I know what you're saying.
Oh yes it is
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Chaps, from someone who's built a few, and spoken to the TWI the old fettle in post 2 is not really current anymore, its boilers under 3bltr, 7 1/4 loco type sized boilers were as big as you go.....
the rules are complex, but basically exemptions DO NOT EXIST, coding is only part of being allowed to make boilers, the design also must be approved, once this is OK the prep, WPS and final inspections are made, by a boiler inspector the boilers then hydraulic to double working pressure, before signing off and and an unique EU code is given for that boiler, inspections are made anually.....
However there is a fudge that applies to some clubs, where you can run with a history, for your own build..... this is getting far more risky tho and many/clubs inspectors now want a 100% reg'd boiler......
You can build a copper one tho, this needs to only be tested, and also adds resale value to the build........
If you want to know more I can go into some detail if you wish....
the rules are complex, but basically exemptions DO NOT EXIST, coding is only part of being allowed to make boilers, the design also must be approved, once this is OK the prep, WPS and final inspections are made, by a boiler inspector the boilers then hydraulic to double working pressure, before signing off and and an unique EU code is given for that boiler, inspections are made anually.....
However there is a fudge that applies to some clubs, where you can run with a history, for your own build..... this is getting far more risky tho and many/clubs inspectors now want a 100% reg'd boiler......
You can build a copper one tho, this needs to only be tested, and also adds resale value to the build........
If you want to know more I can go into some detail if you wish....
Drains
Yeah, nah.
- Messages
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- Sefton, South Island, NZ
I think I was basing my statement on the fact that the pressure is still the same regardless of the volume (which is what I said), but I wasn't accounting for the fact that a greater volume has a relatively smaller outer surface area..., so the relative force (on the surface) is greater.
Does the force go up by the cube, for the same pressure, but increased volume?
Am I on the right lines?
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ermmm I'm lost on the hang up on safe working pressures,
the important thing is volume of superheated liquid, the bigger the boiler the bigger the bomb,a large boiler will have a much larger expansion of gases and potentially more energy in the advent of a major failure, (10ltr water 100ltr of steam as it condenses) this is the whole reasoning behind classifying small boilers as less risk.....
I think a couple of failed foundation rings, and maimed/killed enthusiasts had them re think the regs........
the important thing is volume of superheated liquid, the bigger the boiler the bigger the bomb,a large boiler will have a much larger expansion of gases and potentially more energy in the advent of a major failure, (10ltr water 100ltr of steam as it condenses) this is the whole reasoning behind classifying small boilers as less risk.....
I think a couple of failed foundation rings, and maimed/killed enthusiasts had them re think the regs........
chriskelland
Forum Supporter
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Hi Steamer,
I assume you have talked to your club's boiler inspector? You say 'welded' to me this says a steel boiler. Is the boiler to a proven design? and have you got the certs for the materials? You may well have to go to a recognised boiler maker to have the work done, look in ME or EIM. Have you checked the 'blue book' ? This could? cost as much as having a boiler made. What is the loco?
Give you some idea, I had a copper boiler for a 5 inch Super Simplex built for just under £1500.00.
Chris.
I assume you have talked to your club's boiler inspector? You say 'welded' to me this says a steel boiler. Is the boiler to a proven design? and have you got the certs for the materials? You may well have to go to a recognised boiler maker to have the work done, look in ME or EIM. Have you checked the 'blue book' ? This could? cost as much as having a boiler made. What is the loco?
Give you some idea, I had a copper boiler for a 5 inch Super Simplex built for just under £1500.00.
Chris.
jugs
Dont wish to offend & annoy, but...
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- 1,449
Hi steamer, What loco is it ?, I have a 7 1/4 Bagnall 0-4-0st
As chris says, every bit of material used must be tracable certified boiler plate & first port of call is your local club's boiler inspector as he's the one who will be testing it.
Also, if your not all ready a member, the 7 1/4" soc is well worth joining -
http://www.sevenandaquarter.org/Home/tabid/36/Default.aspx the forum is not as good as this one but the mag is brill and a wealth of info & help is available.
john
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most plans for 7 1/4 give you both option steel or copper, personally iv only ever built steel boilers,
they will vary in cost to build, the simplest will be a Romulus type loco, the boilers are little more than the main tube, firebox, stays and foundation rings...
Something like Hunslets are about double the work due to the shape alone....
IMHO your best taking a visit to your local club, the guys will know who to recommend to help local, the clubs inspector may be happy for all the machining to be done by yourself then know someone who can weld it together, you may wish to just have a boiler maker build the whole thing......
As said by others certs on materials and a aproved design are a must..
with the clubs inspector on side, you can do a complete build in copper (no codings to bog you down), this will cost more in material, but may be cheaper as you will not need and outside help....
whatever you do its worth going to the club first, theres lots of tweaks on the drawings that will make the boiler-es more efficient, and is a good source of ideas even if you don't use em.....
Also worth a mention, iv noticed some of the boiler makers weld the fire tubes in place, if you do get a boiler made insist the tubes are reamed and flared, it makes the boiler an absolute PITA to repair once the tubes need replaceing......
jugs
Dont wish to offend & annoy, but...
- Messages
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Hi hasbeen,
My 7 1/4" Bagnall has a steel boiler & more loco boilers are now being made of steel, partly due to the cost of copper but more because people are going for larger locos.
The difficulties (& cost) of heating a large copper boiler for silver soldering + material cost, are immense & generally outweigh the cost of a professionally built "std" steel boiler.
Some steel boilers use a steel shell & firebox with copper tubes rolled in for greater heat transfer. I know of several 5" locos & one 3 1/2" with steel boilers.
In Europe (but not UK) stainless is often used for 5" & 7 1/4" loco boilers.
john
