I have been calculating pipe spans to be used as a design guide for various materials. One term that keeps coming up is the "Design weight bending stress" which is about an order of magnitude less than the allowable stress of the material. (For carbon Steel)

Does anyone know of a table where I can find these values for other materials? Or how to calculate it?

The seminar notes from the Caesar II seminar also include the reference to this variable on page 2-13 calling the variable Sall. Any COADE guys out there know how to get or find this number?

Tye,

Take a look at B31.1 Table 121.5 - Suggested Pipe Support Spacing. This table matches the numbers in MSS SP-69 Table 3 - Maximum Horizontal Pipe Hanger and Support Spacing. General Note (c) in Table 121.5 says "the spacing is based on a fixed beam support with a bending stress not exceeding 2300 psi ... and the pitch of the line is such that a sag of 0.1 in. between supports is permissable."
There's your "Sall" - 2300 psi. That's roughly 10% of the cold allowable stress.
That pitch is a second criterion to watch.

So is 10% a common standard to use? I am making pipe span table for materials other than carbon steel I'm looking for the criteria for how they come up with the 2300 in that case. I have found various tables where their Sall is slightly different but no one seems to justify how they came up with that number.

Is Sall merely a number that the designer thought would be adequate?

You're looking for a conservative limit that doesn't end up costing too much.
As far as I know, there is no so-called "standard" for support spacing.
You might want to examine the spans for other pipe materials listed in SP-69. Perhaps you will find their criterium.
The Anvil catalog also referernces SP-69. They have a few interesting words about this. You can find the catalog on their web site.

It seems common in contracting companies to use an allowable stress for pipe span definition of 0.25Sh. The logic is that longitudinal pressure stress can be up to 0.5Sh, leave 0.25Sh for other stuff, then 0.25Sh remains for weight, or span.