[modeleng] Re: Model boiler sizes and designs

Barrie
The problem is that the model engineer's boiler testing regime is as  
much an insurance issue as it is to do with boiler test codes.

The majority (nearly all) of model engineering clubs, and their  
boiler inspectors, are covered by insurance schemes arranged by the  
Southern Federation of Model Engineering Societies or the Northern  
Association of Model Engineers. These policies limit models to no  
more than six inch scale (half size) so a model is in a smaller  
representation of a larger prototype (yup, I know about non- 
prototypical designs, ie Simplex). There are some small steam plants  
that were commercially built and marketed for trade/practical use,  
other than as representation of a model of a larger machine. Their  
use could be construed as other than a modeling activity. Now if you  
were to build a boiler that was the same size as was sold to  
originally power such a machine it might not be seen as being a  
model. However, if the boiler could be shown to be a less than six  
inch scale representation of the original design then no problem.   
Hope that all makes sense!!!!!

The boat issue was covered by permitting steam powered plants in  
model boats providing they are a scale model of a full size boat and  
does not carry anyone. (Someone has yet to challenge the scale issue  
by building a half size QE11!!!!)

ChrisC originally wrote........ "Looking for something in the 80-100  
psi range under the assumption that this would be a sensible value  
for a double-expansion engine..."     Unless he is building something  
at an extremely large scale I don't think he will need a boiler that  
will fall outside the code.


Phill wrote:

> Hmmm That doesn't make sense....
>
> How can a 1/12 beam engine not be a model ?????? It is still an  
> industrial
> engine, technically....... But So is a 3.5" gauge loco, still  
> technically a
> locomotive, and therefore not a model.........
>
So a scale boiler for a 1/12 beam engine is not a problem, providing  
it meets the bar-litre criteria.

Want to go bigger than the code/insurance limitations permit, you  
still don't have a problem, you will just  need to get your boiler  
commercially tested.

Regards

Mike Leahy



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