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Length and Spacing Welded Nozzles

Minimum Length and Spacing without Reninforcement

Minimum Length and Spacing without Reninforcement
NPS
of
Nozzle
Center of Nozzle
to
End of Run
A
O.D. of Run
to
End of Nozzle
B
O.D. to O.D.
of Nozzle
C
2.1/2 114 76 76
3 127 89 89
4 152 102 102
5 178 114 114
6 203 127 127
8 254 152 152
10 305 178 178
12 356 203 203
14 381 216 216
16 432 229 229
18 483 254 254
20 533 279 279
24 610 305 305
  Table 1 - 3 

Minimum Length and Spacing with Reninforcement

Minimum Length and Spacing with Reninforcement
NPS
of
Nozzle
Center of Nozzle
to
End of Run
A
O.D. of Run
to
End of Nozzle
B
O.D. to O.D.
of Nozzle
C
2.1/2 152 114 152
3 178 127 178
4 203 140 203
5 241 152 241
6 279 165 279
8 356 203 356
10 432 241 432
12 508 279 508
14 559 305 559
16 635 330 635
18 711 356 711
20 787 381 787
24 914 406 914
  Table 2 - 3 

Minimum Length and Spacing Integrally Reinforced

Minimum Length and Spacing Integrally Reinforced
NPS
of
Nozzle
Center of Nozzle
to
End of Run
A
O.D. of Run
to
End of Nozzle
B
O.D. to O.D.
of Nozzle
C
2.1/2 140 MFR
Standard
76
3 152 76
4 178 89
5 203 102
6 254 127
8 305 152
10 356 178
12 406 216
14 432 229
16 483 254
18 533 279
20 584 305
24 660 356
  Table 3 - 3 

Notes:

  1. MFR = Manufacturer

  2. All nozzle welds should be checked for compliance with the applicable code requirements.
  3. It is preferred that multiple branch openings of in-line nozzles be spaced so that their reinforcement zones do not overlap. If closer specing is necessary, the reinforcement requirements of the applicable construction code shall be met.
  4. Some configurations of integrally reinforced nozzles in combination with certain header sizes may present a problem in the radiographic examination of the attachment weld due to inability to meet the geometric unsharpness requirements of the construction code.
  5. Where attachments such as flanges, fittings valve and pipe insulation are involved, minimum dimensions tabulated may have to be increased to allow for required clearances.
  6. In special cases, it may be possible to reduce the dimensions given in the tables. Such design should then be submitted to the fabricator for individual considerations, as close spacing may involve additional shop operation to prevent, or correct distortion.
  7. Integrally reinforced nozzles are considered to be the commercially available types.
  8. In cases of different nozzle diameters, dimension C, should be determinded on the basis of the larger of the two of adjacted nozzles.

Certain materials and combinations of nozzle and header pipe size and wall thickness together with multiple branch openings welded to a header may result in distortion of the header pipe.

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