ASME B16.01:1998 pdf download CAST IRON PIPE FLANGES AND FLANGED FITTINGs Classes 25,125,and 250
6 FITTING DIMENSIONs AND TOLERANCES6.1 Wal Thickness
lt is recognized that some variations are absolutelyunavoidable in the making of patterns and castings.Equipment shall be designed to produce wall thicknessesgiven in the tables. Wall thickness at no point shallbe less than 87.5% of the thickness given in the tables.
6.2 Facing
6.2.1 Classes 25 and 125 cast iron flanges andflanged fittings shall be flat faced (i.c., without projectionor raised face) and finished in accordance with MssSP-6.
6.2.2Class 250 flanges and flanged fittings shallhave a raised face 0.06 in. high of the dianeters giveninTable 6 and finished in accordance with Mss sP-6. The raised face is included in the minimum flangethickness and center-to-face dimension.
6.3 Center-to-Face Dimensions
6.3.1 Side Outlet Fittings. Side outlet elbows,side outlet tees,and side outlet crosses shall have allopenings on intersecting centerlines. Long-radius elbowswith side outlet shall have the side outlet on the radialcenterline of the elbow.
6.3.2 EIbows
(a) The center-to-face dimensions for straight-size90 deg. elbows，90 deg. long-radius elbows.45 deg.elbows，side-outlet 90 deg. elbows，and double-branchelbows are shown in Tables 3，5,and 7.
(b) Reducing 90 deg. elbows,reducing 90 deg. long-radius elbows,reducing side-outlet 90 deg. elbows,andreducing double-branch elbows shall have . the samecenter-to-face dimensions as straight-size fittings shownin Tables 3,5,and 7 corresponding to the size of thclargest opening.
(c) For 90 deg. long-radius elbows with side outlet,the center-to-face dimensions of the side outlet shallbe the same as dimension A in Tables 3，5,and 7 fora straight-size 90 deg. elbow corresponding to the sizeof the largest opening.
d)Special-degree elbows ranging from 1 deg. to45 deg..inclusive，shall have the same center-to-facedimensions as those for 45 deg.elbows; those over 45 deg. and up to 90 deg.，inclusive, shall have the samecenter-to-face dimensions as those for 90 deg. elbows.The angle designation of an elbow is the angle betweenthe flange faces.
6.3.3 Tees,Crosses,and Laterals
a)The center-to-face dimensions for straight-sizctees and crosses, with or without side outlet,and lateralsarc shown in Tables 3，5,and 7.
(b) Reducing tees and reducing crosses，with orwithout side outlet. and reducing laterals,NPS 16 andsmaller，shall have the same center-to-face dimensionsas straight-size fittings shown in Tables 3、5,and 7
corresponding to the size of the largest opening. ForNPS i8 and larger. if the outlet of a reducing tee; thebranch of a reducing lateral; or the largest outlet of areducing side outlet tee，reducing cross,and reducing
side outlet cross is the same size or smaller than givenin Tables 3，5,and 7 (short body pattern). the center-
to-face dimensions shown in these Tables shall be used.
If a branch or any outlet is larger than shown in Tables3，5.and 7. the center-to-face dimensions shall be the
same as for the straight-size fitting shown in Tables3，5,and 7 corresponding to the size of the largestopening. Tees,crosses,and laterals，reducing on therun only, shall have the same center-to-face dimensionsas straight-size fittings shown inTables 3，5,and7corresponding to the size of the largest opening.
(c) Tees reducing on both runs are generally knownas bull-head tees and have the same centcr-to-facedimensions as straight-size fittings corresponding to thesize of the outlet.
6.3.4 True Ys. Center-to-face dimensions forstraight-size true Ys are shown in Tables 5 and 7.Reducing sizes are considered special and should bemade to suit conditions.
6.3.5 Reducers and Eccentric Reducers. Theface-to-face dimensions for all reductions of reducersand eccentric reducers shall be the same as given inTables 5 and 7 for the largest opening.
6.4 Center-to-Face Tolerances
The following tolerances shall be permitted on allcenter-to-contact surface dimensions of fittings: Toler-ances for contact surface-to-contact surface dimensionsshall be twice those given below. The largest openingin the fitting governs the tolerance to be applied toall openings.
6.5 Threaded Flanges
6.5.1 General. Flanges shall have a Standard TaperPipe Thread in accordance with ASME B1.20.1. Thethread shall be concentric with the axis of the flange,and variations in alignment shall not exceed 0.06 in./ft. The gaging notch of working gage should comeflush with the bottom of chamfer， and the maximumallowable thread variations are one turn large or oneturn small from the gaging notch.
6.5.2 Class 125.Threads shall be countersunk adistance not less than one-half of the pitch of thethread at an angle approximately 45 deg. with the axisof the thread, for the purpose of easy entrance inmaking the joint and protection of the threads.Counter-sinking shail be concentric with the threads.The lengthof the threads shall be measured to include thc coun-tersink.
6.5.3 Class 250.Hub may be recessed. When notrecessed,threads shall be countersunk a distance notless than one-half of the pitch of the thread at an angleapproximately 45 deg. with the axis of the thread atthe back of the flange. If hub is recessed, threads shallbe 45 deg. countersunk to diameter of reeess. Thepurpose is for easier entrance in making a joint andfor the protection of the threads. Countersinking shallbe concentric with the threads. The length of threadsshall be measured to include the countersink.
6.6 Flange Bolt Holes
Flange bolt holes shall be in accordance with thedimensions shown in Tables 2.4.and 6. Pairs of boltholes shall straddle the centerline.
ASME B16.01:1998 pdf download
