Please find the following noteworthy differences between the two:

• WRC-107, entitled “Local Stresses in Spherical and Cylindrical Shells due to External Loadings”, was released in 1965 and updated in 1979. WRC-297 was released in 1984 and goes under the title of “Local Stresses in Cylindrical Shells due to External Loadings –Supplement to WRC Bulletin No. 107”
• Both deal with “local” stress states in the vicinity of an attachment to a vessel or pipe. As indicated by their titles, WRC-107 can be used for attachments to both spherical and cylindrical shells while WRC-297 only addresses cylinder to cylinder connections. While both bulletins
are used for nozzle connection. WRC-107 is based on un-penetrated shell, while WRC-297 assumes a circular opening in vessel. Both bulletins assume that the nozzle (or attachment) axis is normal to the vessel. Furthermore, WRC-107 defines values for solid and hollow attachments of either round and rectangular shape for spherical shells but drops the solid/hollow distinction for attachments to cylindrical shells. WRC-297, on the other hand, is intended only for cylindrical nozzles attached to cylindrical shells.
• The cook-book approach found in WRC-107 resulted from the analytical work of Prof. P. P. Bijlaard and assume a shallow shell theory for spherical shells and flexible loading surfaces for cylindrical vessels. Therefore, WRC-107 requires that the Dm/T ratio be greater than 50 and
limits the d/D ratio to below 0.3.
• WRC-297 can be applied to a larger d/D ratio (up to 0.5) since the analysis is based on a different, thin shell theory (derived and developed by Prof. C. R. Steele).
• WRC-107 only computes the stress states of the vessel/header shell while WRC-297 also provides stress states for the nozzle/branch connection. WRC-297 also provides calculations for nozzle/branch flexibilities.
• Neither bulletin considers shell reinforcement nor do they address stress due to pressure.

SJ

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