t' and tm in ASEM 16.34 Section 6.1.3

[bao2ye]

I would like to get my answer from you expertise.

In ASME 16.34 Section 6.1.3(c)

Valve Body Necks

The thickness of local valve body neck over distance of L shall be equal to t'.

The standard says: the t' value can be obtained from Table 3A.

However, Table 3A only gives Tm ( minimum valve thickness value) and I cannot find the t' data.

Can anyone tell me how to find t' value from the standard?

Thanks in advance.

Bao2