pressure Storage Sphere Construction Testing

6.8 Supports

6.8.1 Supports shall be capable of supporting the sphere full of water.

6.8.2 Spheres, for capacities exceeding 400 m3, shall have tubular steel leg supports welded to the shell.

6.9 Earthing

6.9.1 Pressure Storage Spheres shall be grounded to provide protection against lightning.

6.10 Fire Proofing

6.10.1 Skirts and tubular leg supports of spheres shall be fireproofed up to the shell of the sphere irrespective of its height.

6.10.2 A rain deflector installed on top of the fireproofing shall prevent ingress of moisture.

7. FABRICATION

7.1 Fabrication of pressure Storage Spheres shall meet the requirements of Asme Code Section VIII. Permissible out of roundness for the shells shall be in accordance with the said stipulations.

7.2 The requirements of Section 7 Iranian Petroleum Standard IPS-M-ME-130 “Material and Equipment Standard for Pressure Storage Spheres (For LPG)”.  Shall also be fulfilled. The following requirements shall be considered as supplementary.

7.3 All connections shall be prefabricated and welded to the shell plates e.g. manholes, nozzles, supports, column stubs and major structural attachments. These parts shall be postweld heattreated, if required, as a sub-assembly.

7.4 If the entire sphere is to be postweld heat treated all gussets and lugs shall be welded before the heat treatment. 7.5 Site erected spheres requiring full postweld heat treatment shall have a bottom nozzle of sufficient size to introduce the heating equipment. The piping shall be connected with a reducer to this bottom nozzle.

8. WELDING

8.1 Design of welding for pressure storage spheres shall be per Sub-section B Part UW of ASME Code Section VIII Div.1.

8.2 Use of table UW-12 column C of ASME code Section VIII Div.1 regarding joint efficiency is not permitted.

8.3 Spheres shall be designed with the minimum practical number of weld seams with adequate access for the deposition and inspection of weld metal.

8.4 AS far as possible, seams shall be positioned clear of supports, etc. so as to be readily visible in service after removing any insulation.

8.5 Qualification for welding procedures, welders and welding operators shall be in accordance with the requirement of ASME Code Section IX.

8.6 The minimum preheat temperature for welding shall be per Table 6 of this Standard.

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