ASME B16.42:2021 pdf free download

ASME B16.42:2021 pdf free download.Ductile lron PipeFlanges and Flanged Fittings Classes 150 and 300.
3.4.1 Flange Attachment. Threaded flanges are not recommended for service above 260°C (500°F) ii severe thermal gradients or thermal cyding is involved.
3.4.2 High-Temperature Service. When used above
205°C (400°F), Class 150 flanged joints may develop leakage unless care is taken to avoid imposing severe external loads and/or severe thermal gradients,
3.5 Variances From Ratings
Except as provided herein, ratings are the maximum allowable working pressure for the corresponding temperature.
3.5.1 Safety or ReLief VaLve Operation. Under conditions olsafety valve, relief valve. or rupture disk operation, the pressure on a flange or flanged fitting may exceed the rated pressure at the pressure-relieving temperature by no more than 10%. Such conditions are necessarily of short duration. Overpressure greater than the aforementioned under pressure-relieving conditions is the responsibility of the user, subject to the requirements of the applicable code or regulation.
3.5.2 Other Variances. Operating variations (transients) 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 subected 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.
4 SIZE
4.1 NominaL Size
As applied in this Standard, the use of the phrase nominal pipe size° or the designation NPS followed by a dimensionless number Is for Identifying the end connection of piping, flanges, or flanged fittings. The number is not necessarily the same as the Inside diameter of the flange or flanged fitting. The diameter of a bolt Is Its nominal size. Use of nominal indicates that the stated size or dimension is only for designation, not measurement.
4.2 Reducing Fitting Sizes
Reducing fittings shall be designated by the size of the openings in their proper sequence as indicated in the sketches (see Figure 4.2-1).