6.2 Special Dimensions
6.2.1 FatIgue Loading. For applications where fatigue loading is a concern., required minimum dimensions shall be furnished by the purchaser.
6.2.2 Bore Diameter. Bore diameters away from the ends are not specified. If special flow path requirements are needed, the bore dimensions shall be specified by the purchaser.
6.2.3 Stub Ends. Service conditions and joint construction often dictate stub end length requirements. Therefore, the purchaser must specify long or short pattern fitting when ordering. ISee General Note (c) in Tables 10 and 19.]
Where adjacent openings in fittings are not in parallel planes, they shall be joined by a circular arc or radius on the external surfaces. The arc or radius may be terminated in tangents. Except as provided for block forgings (see para. 5), the projected profile of external surfaces of fittings shall not have sharp intersections (corners) arid/or collapsed arcs.
Unless otherwise specified, the details of the welding end preparation shall be in accordance with Table 1. Transitions from the welding bevel to the outside surface of the fitting and from the root face to the inside surface of the fitting lying within the maximum envelope shown in Fig. 1 axe at the manufacturer’s option, except as covered in Note (5) of Fig. 1 or unless otherwise specifically ordered.
9.1 RequIred Tests
Proof tests shall be made as set forth in this Standard when the manufacturer chooses proof testing to qualify the fitting design. Unless otherwise agreed upon between the manufacturer and purchaser, the proof test shall be one based on the computed bursting pressure of the fitting and Its connecting piping.
Lap joint stub ends are exempt from proof testing because they are used in a flange assembly, which will have different ratings depending on service application.
9.2 Test Assembly
9.2.1 RepresentatIve Components. Fittings that are representative of production and selected for test shall be identified as to material, grade, and lot, including heat treatment. They shall be inspected for dimensional compliance to this Standard.
9.2.2 Other Components. Straight seamless or welded pipe sections whose calculated bursting strength is at least as great as the proof test pressure as calculated In para. 9.3 shall be welded to each end of the fitting to be tested. Any Internal misalignment greater than 1.5 mm (0.06 in.) shall be reduced by taper boring at a slope not over 1:3. Length of pipe sections for closures shall be as follows:
(a) Minimum length of pipe shall be one pipe O.D. for NPS 14 (DN 350) and smaller.
(b) Minimum length of pipe shall be one-half pipe O.D. for NPS greater than 14 (DN 350).
9.3 Test Procedure
Test fluid shall be water or other liquid used for hydrostatic testing. Hydrostatic pressure shall be applied to the assembly. The test is successful if the assembly withstands, without rupture, 105% of the computed proof test pressure defined below.
D = specified outsidediameterof pipe
P = computed minimum proof test pressure for fitting
S = actual tensile strength of the test fitting, determined on a specimen representative of the test fitting, which shall meet the tensile strength requirements of the applicable material of para.
t = nominal pipe wall thickness of the pipe that the fitting marking identifies
NOTE Any dimensionally consistent system of units may be used.
9.4 ApplIcability of Test Results
It Is not necessary to conduct an individual test of fittings with all combinations of sizes, wall thicknesses, and materials. A successful proof test on one representative fitting may represent others to the extent described in paras. 9.4.1, 9.4.2, and 9.4.3.
9.4.1 SIze Range. One test fitting may be used to qualify similarly proportioned fittings with a size range from one-half to twice that for the tested fitting. The test of a nonreducing fitting qualifies reducing fittings of the same pattern. The test of a reducing fitting qualifies reductions to smaller sizes.
9.4.2 ThIckness Range. One test fitting may be used to qualify similarly proportioned fittings with t/D ranges from one-half to three times that for the tested fitting.