1.1 This standard specifies the construction procedures and methods of spherical tanks, as well as the requirements of field assembly welding procedure control, test/inspection/quality specifications and handover specifications.
1.2 This standard is applicable to the construction of orange-segment-model or mixed-model, pillar-supported, carbon steel/low alloy steel-welded spherical tanks (see Annex A) whose design pressure is larger than or equal to 0.1MPa but not larger than 4MPa, and whose nominal volume is larger than or equal to 50m3.
1.3 This standard is applicable to the following construction scopes of spherical tanks (see Article 1.1):
a）Spherical shell plate and its welding joint;
b）Pressure head, flat cover and fastener of spherical tank opening;
c）The following parts where the spherical shell pipes are connected with outside pipe:
1) The first girth joint groove head face of welded connection;
2) The first screwed joint head face of screwed connection;
3) The first flange sealing surface of flanged connection;
d） Non-pressure elements and their connection welds of the spherical tanks such as pillar, pull rod, backing plate and base plate.
1.4 This standard is not applicable to construction of the following spherical tanks:a）Spherical tanks suffering from nuclear radiation;
b）Non-fixed (such as vehicle or ship-borne) spherical tanks;
c）Spherical tanks with double-shell structures;
d）Spherical tanks formed by expansion.
