[Steam-engine] lap seam calculations

[Brice Adams]

Change:

P= (tensile strength)(thickness)(joint
  efficiency)/(shell radius)(safety factor)

to:

(safety factor)= (tensile strength)(thickness)(joint
  efficiency)/(shell radius) P


Then solve for both pressures.  I get 125% but this is a binary problem. 
  It's either safe or it isn't.
Hope this helps.
Brice

steamman at ptdprolog.net wrote:

>Engine friends,
>
>I just came from a show in Maryland. Spent 2 hours with the Chief Inspector 
>and his inspectors going over the interpretation of their antique boiler 
>code. I was limited to 100 lbs. operating pressure because of my lap seam 
>boiler. In PA I'm allowed 125 lbs.  They refer back to the 1971 code for new 
>construction of lap seam boilers. They will not even do any calculations for 
>a lap seam boiler, they flat out say 100 lbs.
>
>I'd like to know if anyone can calculate the difference from 125 lbs to 100 
>lbs for a double riveted lap seam, What I'm really after is just how safe is 
>100 lbs vs 125 lbs.  My last ultra sound on my crown sheet last year was .365 
>around the fusible plug and found the lowest to be .310 in the rear left 
>corner of the crown sheet. My stays are 4 15/16"x 5". It's a 1909 Frick 8 x 
>10 and I very rarely work the engine. I ran a sawmill, thresher and a rock 
>crusher once. I run a baker fan every so often for 15 minutes or so. Other 
>than that I pull a sled just for show.
>
>Lets here everyone's thoughts and comments
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