ASME B16.9 specification is designed for butt welded fittings applied in industrial construction pipelines. Including elbow, tee, cross, cap, reducer, and etc.
The standard includes specifications of NPS 1/2 to NPS 48 (DN15-DN1200) factory-made wrought butt welded pipe fittings overall dimensions, tolerances ratings, test methods and markings.
Special fittings here refers to special sizes, forms and tolerances that agreed between buyer and manufacturer.
Fabricated laterals and other fittings by circumferential or intersection welds are considered pipe fabrication could not apply this standard.
Units under ASME B16.9 shall be stated in both SI (Metric) and U.S. Customary units. Designation for size is NPS.
It is not considered practical to identify the specific edition of each standard and specification in the individual references. A product made comply with a prior edition of referenced standards and in all other respects conforming to this standard will be considered complied.
A fittings sued under ASME Boiler and Pressure Vessel Code (BPVC), the ASME code for pressure piping, or a governmental regulation is subject to any limitation of that code or regulation. It includes any maximum temperature limitation or rule governing the use of material at low temperature.
ASME 16.9 didn't specify the welding specifications, so it is outside this scope.
Standardized designations for flanges as per ASME B16.5 referenced in this standard are Class 150, 300, 600, 900, 1500 and 2500.
Fittings under ASME B16.9 are expressed in NPS. It is related to reference nominal diameter, DN, used in international standards. Typically as below:
For NPS > 4, the equivalent is DN = 25 X NPS.
Each pipe fitting marks permanently , indicating the following content:
The name or trademark of the manufacturer
Material identification mark (ASTM or ASME level symbol)
Wall thickness serial number or nominal wall thickness
Specifications – Engineering pipe diameter (NPS) related to end connection should be used
Compliance – standard and special pipe fittings
When the specifications of the pipe fitting are all not allowed to mark, the identification mark may be omitted in the reverse order.
When using the steel stamp, it should not too deep or too sharp cause cracking or to reduce the wall thickness to less than the minimum allowance of wall thickness.
Standard Fittings: Means the fittings manufactured comply with this standard, including all dimensional requirement, is certified by a prefix "WP" in the material grade designation.
Special fittings: The fittings manufactured with this standard, except that dimensional requirements are as agreed between the purchaser and manufacturer, is certified by a supplementary suffix to the material grade designation marking as follows:
Wrought fittings covered by this Standard shall be in accordance with ASTM A234, ASTM A403, ASTM A420, ASTM A815, ASTM B361, ASTM B363, ASTM B366, or the corresponding specification listed in ASME BPVC, Section II. The term “wrought” denotes fittings made of pipe, tubing, plate, or forgings.
This Standard provides for a fixed position for the welding ends with reference to either the centerline of the fittings or the overall dimensions. Dimensional requirements for these fittings are in below links.
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.
Unless otherwise specified, the details of the welding end preparation shall be in accordance with Table 8-1. 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 Figure 8-1 are at the manufacturer’s option, except as covered in Note (5) of Figure 8-1 or unless otherwise specifically ordered.
Hydrostatic testing of wrought fittings is not required by this Standard. All fittings shall be capable of withstanding, without leakage or impairment of serviceability, a hydrostatic test pressure required by the applicable piping code for seamless pipe of material equivalent to the fitting material, and of the size and wall thickness the fitting marking identifies.
Tolerances for fittings are shown in Table 11-1 and apply to the nominal dimensions given for each of type fittings. Where given for the fittings, the minimum and maximum dimensions are based on these tolerances. The listings with decimals do not imply precision measurement, such as use of vernier, micrometer, or electronic readout equipment.