ASME B16.9:2018 pdf free download – Factory-Made Wrought Buttwelding Fittings
1.1 General
This Standard covers overall dimensions, tolerances, ratings, testing, and markings for factory-made wrought buttwelding fittings in sizes NPS 1 ∕ 2 through NPS 48 (DN 15 through DN 1200).
1.2 Special Fittings
Fittings may be made to special dimensions, sizes, shapes, and tolerances by agreement between the man- ufacturer and the purchaser.
1.3 Fabricated Fittings
This Standard states values in both SI (Metric) and U.S. Customary units. These systems of units are to be regarded separately as standard. Within the text and tables, the U.S. Customaryunits are shown inparentheses. Thevaluesstatedineachsystemarenotexactequivalents; therefore, it is required that each system ofunits be used independently of the other. Combining values from the two systems constitutes nonconformance with the Standard. The designation for size is NPS for both Metric- and Customary-dimensioned fittings. Fitting pressure rating is associated with the connecting wall thickness of pipe of equivalent size and material.
1.5.1 Referenced Standards. Standards and specifica- tions adopted by reference in this Standard are shown in Mandatory Appendix I. It is not considered practical to identify the specific edition of each standard and specifi- cation in the individual references. Instead, the specific edition reference is identified in Mandatory Appendix I. A product made in conformance with a prior edition of referenced standards and in all other respects conforming to this Standard will be considered to be in conformance.
1.9 Convention
For determining conformance with this Standard, the convention for fixing significant digits where limits (maximum and minimum values) are specified shall be as defined in ASTM E29. This requires that an observed orcalculatedvalueberoundedofftothenearestunitinthe lastright-hand digitused forexpressingthe limit. Decimal values and tolerances do notimply a particular method of measurement.
1.10 Pressure Rating
Designation Class followed by a dimensionless number is the des- ignation for pressure–temperature ratings. Standardized designationsforflangesperASME B16.5 referencedinthis Standard are Classes 150, 300, 600, 900, 1500, and 2500.
2.1 Basis of Ratings
The allowable pressure ratings for fittings designed in accordance with this Standard may be calculated as for straight seamless pipe of equivalent material (as shown by comparison of composition and mechanical properties in the respective material specifications) in accordance with the rules established in the applicable sections of ASME B31, Code for Pressure Piping. For the calculation, applicable data for the pipe size, wall thickness, and material that are equivalent to that of the fitting shall be used. Pipe size, wall thickness (or schedule number), and material identityon the fittings are inlieu of pressure rating markings.
When special elbows are intended for field segmenting, theoutsideorinsidediametertoleranceshallbefurnished throughout the fitting by agreement between the manu- facturer and the purchaser. Any mismatch on the outside or inside diameter needs to be corrected in the field by grinding, back-welding, or bridging of weld to meet the applicable piping code requirements. Although the elbow intended for field segmenting must meet the re- quirements of this Standard, once the field-segmented elbow is cut, it is not a B16.9 product.
7 SURFACE CONTOURS
Where adjacent openings in fittings are not in parallel planes, they shall be joined by a circular arc or radius on theexternalsurfaces. Thearcorradius maybe terminated in tangents. Except as provided for block forgings (see section 5), the projected profile of external surfaces of fittings shall not have sharp intersections (corners) and/or collapsed arcs.
8 END PREPARATION
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.