offer:  ASME B16.11 coupling NPT/socket weld
   
                                        socket weld                                                                        NPT         
      
                               3000lb         6000lb       9000lb                        2000lb    3000lb      6000lb

45/90 elbow         1/8-4            1/8-2           1/2-2                           1/8-4         1/8-4       1/8-4

tee/cross               1/8-4            1/8-2           1/2-2                           1/8-4         1/8-4       1/8-4

coupling                1/8-4            1/8-2           1/2-2                                              1/8-4       1/8-4

cap                          1/8-4            1/8-2           1/2-2                                             1/8-4       1/8-4