pressure Storage Sphere Shop inspection

6.5.8 For nozzles fabricated from pipe, only seamless pipe shall be used.

6.5.9 Forged integral reinforced long-welding neck nozzles shall be used for flange rating of PN 100 (ANSI Class 600) and higher.

6.5.10 Nozzles shall normally be designed as set-through types and be double welded, from both sides.

6.5.11 Necks of nozzles with sizes DN 350 (14 in.) and larger and manholes may be made of plate materials. Where plate materials are used for nozzle and Manhole necks, the method specified in ASTM A-672 shall be used and the material specification shall be the same as those used for Pressure Storage shells and full radiographic examination of longitudinal joints shall be conducted.

6.5.12 All flanges except those indicated in items 6.5.14 and 6.5.15 below shall conform to ANSI B 16.5, PN 50.

6.5.13 All nozzle flanges shall be welding neck and raised face type smooth finish, except that manhole flanges may be slip-on flange type. Where slip-on flanges are used, they shall be welded both sides.

6.5.14 Non-standard flanges shall be calculated per ASME code Section VIII, Div. 1 Appendix 2 according to the design conditions of the pressure storage Sphere and external loads imposed by piping reaction.

6.5.15 Large type flanges over DN 600 (24 in. NPS) shall be in accordance with IPS-M-PI-150.

6.5.16 A DN 500 (20 in NPS) minimum manhole shall be provided in the top and bottom of each sphere. Generally top manhole shall have a davit and bottom manhole shall have a hinge.

6.5.17 Minimum Projection of nozzles and manholes shall normally be 150 mm for nozzle size up to DN 150 (6 in. NPS), and 200 mm for DN 200 (8 in. NPS) and over.

6.5.18 The necessity of reinforcing pad on the shell around nozzle opening shall be determined using the procedures outlined in ASME Code Section VIII.  As a general rule nozzles of DN 50 (2 in. NPS) and over and manholes should be provided with a reinforcing pad and smaller size nozzles shall be provided with a half coupling type reinforcement except in case of item 6.5.8 above.

6.6 Mountings

6.6.1 Pressure storage spheres, upon approval of the owner, shall be provided with the followings:

6.6.2 Sample outlet

Sample outlet shall be provided with double block and bleed valves located at places where they are convenient to the user.

6.6.3 Water draw-off

a) If a water draw-off is specified for spheres which will operate in a freezing climate, it shall be per Fig. 1 if it is possible for water to accumulate and freeze in bottom manhole, the draw-off pipe shall be extended down to within 75 mm. of the manhole cover. A union shall be provided at the turn-down point above the manhole to facilitate access. If the sphere is to be used for storage of materials subject to polymerization or formation of peroxide, i.e., butadiene,isoprene, etc., the internal water draw-off piping shall be deleted and the draw-off connection shall be flushed with the bottom.

b) If water draw-off is specified for spheres in a nonfreezing climatic location and the product will autorefrigerate below 0°C on reduction to atmospheric pressure, the water draw-off may be located in the bottom of the sphere, bottom manhole cover plate, or on a bottom nozzle without internal riser, whichever location provides for all water removal .The water draw-off shall be at least DN 20 but shall not exceed DN 50. and shall be equipped with two valves at least 150 mm apart. The valve nearest the vessel shall be of the quick closing type, such as a plug valve (ball valves are not permitted unless certified “Fire-Safe”).

c) The water draw-off line shall terminate at a minimum of 500 mm. from the sphere.

6.6.4 Suction internal extension

The hydrocarbon pump suction internal extension shall be 150 mm above the bottom tangent of the sphere or 150 mm above the water draw-off inlet, whichever is higher.

pressure storage sphere shop inspection -will be continued