A.R.C. Markl in his paper "Piping Flexibility Analysis" set the Expansion Allowable Stress Range so as not to exceed twice the yield stress, times a safety factor, times a cyclic reduction factor minus the mean stress. The total stress range (expansion plus sustained)was set as twice the yield stress.
I don´t know how the equation for the Expansion Allowable Stress Range was set:
SA < f(1.25 Sc + 1.25 Sh) - Sl.

Hi Edgar,

I think the answer that you are looking for can be found in a previous thread. See the discussion on this board below under:

PRACTICAL USAGE OF LIBERAL ALLOWABLE STRESS.

By all means, if you have further questions please post them on this board.

Best regards, John

The direct link to the thread John mentions is: http://www.coade.com/ubb/Forum1/HTML/000057.html .

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Regards,
Richard Ay (COADE, Inc.)