When designing, are there any regulations on the minimum distance between flanges, tees, or valves? Or what information should I check?

You can refer to the piping design manual. Let me introduce to you the ASME standards used by our company.: Flanges, elbows, tees, etc. can be connected directly, which means there is no need to use short pipes to connect, and there is no minimum distance. If sometimes it is necessary to use a short pipe to connect, the short pipe is required to have a minimum length. This minimum length standard can be found in the standard. For example, the minimum pup joint of a 3" pipe is 50mm.

There is this passage in Chapter 14 of the "Chemical Process Design Manual": When using formed seamless pipe fittings (elbows, reducers, tees), they should not be welded with flat welding flanges (can be directly welded with butt welding flanges). A section of straight pipe should be added in between. The length of the straight pipe is generally not less than its nominal diameter, and the minimum is not less than 100mm.

I have information about the minimum size of connections between pipes and pipe fittings, which can be found in general petrochemical pipeline installation books. 1. Scope This standard applies to the minimum connection size between ANSI pipe fittings and SH series pipe fittings, GB flanges (PN2.0, 5.0, 10.0, 15.0, 25.0, 42.0MPa) and JPI flange pipe components. This standard applies to the minimum connection size between the above pipe fittings and JIS flanges. This standard does not apply to the connection between ANSI pipe fittings, SH pipe fittings and JB flanges. 2. General provisions 2.1 All types of pipeline components used in this standard shall comply with the following provisions. Pipe fittings Steel butt welding seamless pipe fittings ANSI B16.9 JIS B2311 JIS B2312 SH3408-1996 Steel plate butt welding pipe fittings ANSI B16.9 JIS B2311 JIS B2312 SHJ409-1996 Forged steel socket welding pipe fittings ANSI B16.11 JIS B2311 SH3410-1996 Steel pipe flange ANSI B16.5 JIS B2212 JIS B2224 JIS B2233 JPI 7S-15 SH3406-1996 GB9115.12-88 GB9115.13-88 GB9115.14-88 GB9115.32-88 GB9115.33-88 GB9115.34-88 GB9115.35-88 GB9115.36-88 GB9116.8-88 GB9116.9-88 GB9116.10-88 GB9117.2-88 GB9117.3-88 GB9117.4-88 Valve ANSI B16.34 API600 API602 2.2 Pipe specifications and wall thickness should comply with the regulations of "Steel Pipe Dimension Series for Petrochemical Enterprises" (SH3405-1996) or "Welded and Seamless Wrought Steel Pipe" (ANSI B36.10) and "Stainless Pipe" (ANSI B36.19). 2.3 The weld gap between butt-welded pipe fittings is calculated as zero. 2.4 The connection dimensions of elbows are calculated based on long-radius elbows. When short-radius elbows are used, recalculation is required. 2.5 The connection dimensions "H" and "J" between the flange and the tee are calculated based on the size (M value) of the equal diameter tee. When using the reducing tee, it needs to be recalculated, that is, the tee M value + the flange D value (E value). 2.6 The connection between flanges shall be considered as double-headed studs, and the stud length shall be determined as thickened nuts. When using thin nuts, recalculation is required. 3. Explanation of symbols 3.1 The symbols used in the minimum dimensions of pipe connections are as follows:: A ----- ANSI J ----- JIS, JPI L ----- Long radius 900 butt welding elbow size ； S ----- Short radius 900 butt welding elbow size ； D ----- Minimum size of flat welding flange plus straight pipe ； E ----- Butt welding flange height ； F ----- Minimum size determined by long radius elbow size and "D" value ； G ----- Minimum size determined by long radius elbow size and "E" value ； H ----- Minimum size determined by equal diameter tee size and "D" value ； J ----- Minimum size determined by equal diameter tee size and "E" value ； SO ---- Flat welding flange SW --- Socket welding flange WN ----- Butt welding flange 3.2 The symbols used in various valve sizes are as follows: L1 ----- Structural length of various flange valves H0 ----- Valve stem height when fully open or check valve convex height D0 ----- Valve handwheel diameter 4. Sorry for the minimum size of pipe connection. I have to use a WORD document and cannot upload it. This post was last edited by chenglx at 2009-3-1 15:53 ]

Yes, in addition to the corresponding design specifications, it also depends on the actual situation. Each design institute is different.

The distance between the two welds, that is, the length of the short pipe, is required. It must be greater than 75mm for less than 2 inches, and greater than 100mm for more than 2 inches. Marine engineering specifications

This should be related to the girth weld spacing. The minimum spacing for nominal diameter DN150 is 150mm. It's written in the pipe installation manual.