As I stare at my copy of the CFR title 49 part 230 form 4, I came to wonder, how does one go about figuring the calculations for things such as staybolt, brace, shearing etc. stresses as well as minimum thickness and things of that nature? Are there certain formulas one has to use to come up with them?

Particularly, I was wondering if after say installing a staybolt or two, the stress calculations that have to be done (if any if that's considered as an alteration under the CFR) once the work is completed. Hope someone can shed some light on this for me.

Regards
Brian O.

Hello Brian,
In fact there is a set of calculations involved in order to address the current FRA rules. Interestingly they have been compiled into a single volume titled "COMPENDIUM Volume 1, Compilation of Calculations", dated 1 Dec.2001.
This work was generated by the Engineering Standards Committe, the same organization responsible for developing the new rules.
You can acquire a copy by contacting me at sar16e@yahoo.com
The question of whether a work done to a boiler is considered a repair or an alteration takes a bit of study in Part 230, but can be clearly defined by describing the work then comparing to the various paragraphs covering the rules being implemented.
If you need help on this we would be pleased to try to answer your questions.
Respectfully,
Dave Griner
Chief Mechanical Officer
Wasatch Railroad Contractors

Brian,

There are some very good resources available from which one can obtain the needed formulas. One of the best is the 1952 edition of the ASME Boiler & Pressure Vessel code. It has a specific section on locomotive boilers. Reprints are available...if not from ASME directly, then I think the National Board of Boiler & Pressure Vessel Inspectors has them. While these formulas are intended for someone with a mechanical engineering background, a person good in math, science or physics should be able to understand many of them.

According to CFR 230.8 an alteration is "Any change to the boiler which affects its pressure retention capability. Rating changes are considered alterations." I will let someone with a little more experience than me comment on that broad statement and how it applies if you are just replacing a broken stay with an exact duplicate...can't find my 230 with the interpretations at the moment...

If you are changing the size, number or type of staybolts then the appropriate paperwork must be filed. For your own SAFETY and that of those around you...do the calculations!

I am currently about 1/2 way thru creating an excel spread sheet to do this.
I need to get back on the program and finish it.
i have gotten a lot of the formula's and explainations from 2 books

boilers, pipes, & plumbing by Hubert E. Collins, printed by Mcgraw Hill (1908)
&
Maxims and Instructions for the boiler room by Halkins, printed by Theo Audel (1899) on google books for free

search google book for anything else and let me know if you find anything else good

dr