pressure Storage Sphere Purchasing inspection

6.4 Minimum Required Thickness

6.4.1 Minimum required thickness of shell plate for Pressure Storage sphere shall be calculated per

ASME “Pressure Vessel Code” Section VIII.

6.4.2 The thicknesses calculated using the procedures outlined in 6.4.1 above excluding any corrosion allowance.

6.5 Nozzles and Connections

6.5.1 Nozzles and connections design for Pressure Storage Spheres shall be in accordance with ASME Code Section VIII with the following supplementary requirements.

6.5.2 Attachments and shell openings, wherever practicable, shall be located so that the welds do not overlap shell seams or interfere with welds of other attachments.

6.5.3 All nozzles for piping shall be flanged and shall have the same P-number as the sphere shell. Corrosion protection equivalent to that of the sphere shall be provided.

6.5.4 Connections smaller than DN-50 (2 in.) may be threaded, except for relief valve connections. Coupling shall be used for threaded connections. Additional coupling-thickness shall be provided for corrosion allowance, as required. All couplings shall be installed with full penetration welds.

6.5.5 Nozzles and openings in the bottoms of pressure storage spheres shall be kept as minimum as possible. Connections to the storage sphere shall be positioned, as much as possible, above the maximum liquid level.

6.5.6 The design of nozzles pipe is governed by the following three main considerations:

6.5.6.1 Ability to withstand design pressure. For this purpose the minimum thickness of nozzle shall be calculated in accordance with ASME Code Section VIII for cylindrical shells.

6.5.6.2 Ability to withstand superimposed loading by connected pipe work or fittings. Not conforming to the minimum thickness as required for 6.5.6.1, the nominal thickness of a nozzle intended for connection to external piping shall not be less than:

a) The value given in Table 5 increased by any required corrosion allowance.

b) The nominal (As-built) thickness of the main portion of the vessel shell where this is less than (a) above.

6.5.6.3 Suitability for the recommended forms of branch-to shell attachment welds.

6.5.7 Threaded connections shall not be permitted for piping.

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