ASME B16.42:2016 pdf free download – Ductile Iron Pipe Flanges and Flanged Fittings
3.2 Ratings of Flanged Joints
Ratings in this Standard apply to flanged joints that conform to the limitations on bolting in para. 6.2 and on gaskets in para. 7.8, and which are made up in accor- dance with good practice for alignment and assembly. See also para. 3.4. Use of the ratings for flanged joints not conforming to these limitations is the sole responsibility of the user. A flanged joint is composed of separate and indepen- dent, although interrelated, components: the flanges, the gasket, and the bolting, which are assembled by another influence, the assembler. Proper controls must be exer- cised in the selection and application for all these ele- ments to attain a joint that has acceptable leak tightness. Special techniques, such as controlled bolt tightening, are described in ASME PCC-1 . If the two flanges in a flanged joint do not have the same pressure– temperature ratings, the rating of the joint at any temperature is the lower of the two flange ratings at that temperature.
3.3 Rating Temperature
Temperatures shown for corresponding pressure rat- ing shall be the material temperature of the pressure- retaining structure. It may be assumed that the material temperature is the same as the fluid temperature. Use of a pressure rating at a material temperature other than that of the contained fluid is the responsibility of the user and subject to the requirements of any applicable code or regulation.
3.4 Temperature Considerations
Application of the ratings in this Standard to flanged joints at both high and low temperatures shall take into consideration the risk of leakage due to forces and moments developed in the connected piping or equip- ment. The provisions in paras. 3.4.1 and 3.4.2 are intended to minimize these risks.
3.5.2 Other Variances. Operating variations (tran- sients) that subject a flange or flanged fitting to pressure in excess of the rated pressure at the corresponding temperature are the responsibility of the user, subject to the requirements of the applicable code or regulation.
3.5.3 System Hydrostatic Test. Flanged joints and flanged fittings may be subjected to system hydrostatic tests at a pressure not to exceed the hydrostatic shell test pressure specified in para. 9.3. Testing at any higher pressure is the responsibility of the user.
7.1.2 Reducing Fittings. Center-to-contact-surface or center-to-flange-edge dimensions for all openings shall be the same as those of straight size fittings of the largest opening. The contact-surface-to-contact-surface dimensions for all combinations of reducers and eccen- tric reducers shall be as listed for the larger opening.
7.2.2 Facings of Blind Flanges. Blind flanges need not be faced in the center if, when this center part is raised, its diameter is at least 25.4 mm (1 in.) smaller than the inside diameter of the corresponding pressure class fittings, as given in the tables. When the center part is depressed, its diameter shall not be greater than the inside diameter of the corresponding pressure-class fittings, as given in the tables. Machining of the depressed center is not required.