Pipe Rack Designer — Companion Article

What this tool does

The Pipe Rack Designer lays out a list of lines across the tiers of a pipe rack. It works out each line’s envelope, assigns lines to tiers, places them side by side on each tier, and reports the tier widths, the working width, a future allowance, and a recommended rack width. It also checks the vertical spacing between tiers.

The result is drawn as an elevation and a plan, with a results table. The drawing can be downloaded as SVG or PDF and the line list as CSV.

Every result is marked preliminary. It is a geometric planning estimate, not a structural design.

When to use it

Use it early in layout, when you have a line list with sizes and insulation and need a first rack width and tier count. Use it to compare options: more tiers, a wider corridor, flanges staggered or side by side, or tighter clearances.

Use the line spacing calculator when you only need the centre-to-centre spacing between two lines. Use the rack and process spans tool for the span between rack bents.

Inputs

Rack settings, with the values the page opens on:

1. Tiers: 2.
2. Tier spacing, mm: 1800. Leave it blank to use the computed minimum.
3. Line-to-line clearance, mm: 75.
4. Edge clearance, mm: 150.
5. Future expansion, %: 20.
6. Corridor side: right, left, both, or none. The page opens on right.
7. Corridor width, mm: 750.
8. Base elevation, mm: 4500. This is the top of steel of the first tier.
9. Maximum width, mm: blank. Set it to have the page test ways to fit inside that width.
10. Minimum line-to-line, minimum edge, and minimum local clearance, mm: 25, 50, and 25. These are used only when the page tests reduced clearances.
11. Flange arrangement: staggered, or side by side.

Lines, one row each:

1. Line ID and Service.
2. NPS and Schedule.
3. Insulation, mm.
4. Flange allowance, mm.
5. Flange class, optional: an ASME B16.5 class from 150 to 2500.
6. Shoe, mm, with a No shoe tick.
7. Tier: a tier number, or auto.

The page opens with a 12-line example. Rows can be added, deleted, pasted from Excel, or imported from CSV. The page holds 150 lines. Your work is kept in the browser. Save project is for members and is not open yet.

How it works

Outside diameter comes from the NPS and the schedule. A carbon steel schedule, or no schedule, uses the interim ASME B36.10 outside diameter. 5S, 10S, 40S, and 80S use the interim ASME B36.19 outside diameter. The wall is not used.

Each line has a width envelope. The pipe envelope is the outside diameter plus twice the insulation plus a 50 mm local clearance. The flange envelope is the outside diameter plus twice the insulation plus the flange allowance. The larger of the two is the line’s envelope.

A line with a tier number stays on that tier. Auto lines are sorted widest envelope first. Each goes to the tier with the least total envelope width so far.

On each tier the page starts at the edge clearance and places the envelopes side by side, with the line-to-line clearance between them and the edge clearance at the far end. That total is the tier width. Without a flange class, the centre-to-centre spacing of two neighbours is half of each envelope plus the line-to-line clearance.

When a line has a flange class, the page reads the ASME B16.5 weld neck flange outside diameter for that NPS and class. Staggered flanges set the centre-to-centre spacing to the larger of half flange A plus half pipe B, or half pipe A plus half flange B, then add both insulations and the line-to-line clearance. Side by side uses half of each flange instead, and never less than staggered.

The pipe bay is the widest tier. The working width is the pipe bay plus the corridor, or twice the corridor when it is on both sides. The future allowance is the working width times the percentage. The recommended width is the working width plus the future allowance.

Bottoms of pipe sit on the beam. Lines are not centre-aligned. The bottom of pipe is the top of steel plus the shoe. A typed shoe is used as typed. No shoe is zero. An insulated line with a blank or zero shoe gets insulation plus 25 mm, rounded up to 100, 150, or 200 mm, then in 50 mm steps. A bare line with a blank shoe sits on the steel.

The tier spacing check takes the line with the largest outside diameter on each tier. Its minimum is shoe plus insulation plus an elbow, twice, plus 50 mm. The elbow is 1.5 times the NPS, converted at 25.4 mm per inch. No ASME B16.9 centre-to-end table is stored. With a typed spacing below a tier’s minimum, the page warns and still draws the typed spacing. With a blank spacing it uses the largest tier minimum. When no tier has a line with a nominal size, it uses 300 mm.

When a maximum width is set and the rack is wider, the page tests three options: add a tier, move the largest lines to another tier, and reduce clearances to the stated minimums. If none fits, it tests combinations. If still none fits, it reports the narrowest width it can reach. Each option shows its recommended width and can be applied.

Understanding the result

The drawing shows the rack in elevation and in plan, in one SVG. Each tier is labelled with its beam top of steel, for example T1 TOS 4500. The future allowance is hatched and the corridor is marked on the side you chose.

Under the drawing the page states the tier spacing used and whether it was entered or computed. Each tier minimum follows, with the line that governs it and the sum, for example Shoe 0 + insulation 0 + 1.5D elbow 609.6 + 1.5D elbow 609.6 + insulation 0 + 50 = 1269.2 mm. Each tier then lists its lines in order, with the centre-to-centre spacing between neighbours and its basis: default, or flange-based.

The figures panel shows Working width, Recommended width, Lines per tier, and Clashes. The Spacing basis column in the line table repeats each line’s basis and spacing. Export CSV adds each line’s outside diameter, centre position, centre elevation, and bottom of pipe.

The warnings start with three preliminary statements. The first reads: PRELIMINARY TOOL: this is a geometric planning estimate, not a final engineering or structural design. Other warnings report the shoe rule and the tier spacing check.

Lock tiers fixes the current tiers and order. Lines can then be moved up and down, or dragged, within a tier. A locked layout is marked Locked / manual order, and the lock is kept in the downloads and in the browser. Unlock / reset to auto returns to automatic assignment.

The PDF is the same drawing on a landscape A4 or A3 page, with a title block and the results on the next page.

Engineering considerations

The width is driven by the envelopes, so the flange allowance and the insulation matter as much as the pipe size. Check the flange allowance against the valves and flanges actually on the line.

The tier spacing minimum uses the largest line on each tier. A smaller line with thicker insulation or a taller shoe can need more room. Check those lines by hand.

One spacing is applied to every tier. The elbow is 1.5 times the NPS, not a fitting table. Large-bore drops and branch take-offs need their own check.

The future allowance is a percentage of the working width, which includes the corridor.

Support loads, structural steel, thermal movement, fireproofing, and access are not fully checked. Valve and instrument geometry is included only when you give an envelope for it.

Example

The 12-line example the page opens with. Two tiers, 1800 mm spacing, 75 mm line-to-line, 150 mm edge, 20% future, a 750 mm corridor on the right, base elevation 4500 mm, flanges staggered.

Line 10-P-1101 is NPS 10, Schedule 40, 50 mm insulation, 80 mm flange allowance. Its outside diameter is 273.0 mm. The pipe envelope is 273.0 + 100 + 50 = 423 mm. The flange envelope is 273.0 + 100 + 80 = 453 mm. The envelope is 453 mm. Its shoe is blank and it is insulated, so it gets 50 + 25 = 75 mm, rounded up to 100 mm.

Tier 1 holds 12-CW-1001, 16-CW-1002, 10-P-1101, 6-P-1103, 2-PW-1602, and 2-N2-1601. Tier 2 holds 8-HO-1201, 6-ST-1301, 4-IA-1401, 8-P-1102, 4-SC-1302, and 3-FG-1501.

• Tier 1 width 2527.1 mm. Tier 2 width 2424 mm.
• Pipe bay 2527.1 mm.
• Working width 3277.1 mm, including the 750 mm corridor.
• Future allowance 655.4 mm.
• Recommended width 3932.5 mm.
• Beam top of steel 4500 mm and 6300 mm.

Centre-to-centre spacing. 12-CW-1001 has a 373.8 mm envelope and 16-CW-1002 a 456.4 mm envelope. 373.8/2 + 456.4/2 + 75 = 490.1 mm, shown as default, 490.1 mm centre to centre.

Tier spacing check. On tier 1 the largest line is 16-CW-1002, bare with no shoe: 0 + 0 + 609.6 + 609.6 + 0 + 50 = 1269.2 mm. On tier 2 it is 8-HO-1201, 80 mm insulation, 150 mm shoe: 150 + 80 + 304.8 + 304.8 + 80 + 50 = 969.6 mm. 1800 mm is above both. With the spacing left blank, the page uses 1269.2 mm and the second beam is at 5769.2 mm.

Flange spacing. NPS 8 and NPS 6 bare lines, both Class 300, 75 mm clearance. The flange outside diameters read are 381 mm and 317.5 mm. Staggered: the larger of 381/2 + 168.28/2 and 219.08/2 + 317.5/2 is 274.64 mm, plus 75 mm gives 349.64 mm. Side by side: 381/2 + 317.5/2 + 75 = 424.25 mm.

Standards/references (licensed vs interim)

The outside diameters and flange diameters are interim data from public sources, pending the licensed standard.

Pipe outside diameters are the interim ASME B36.10-2022 Table 2-1 outside diameter column, and the ASME B36.19 outside diameter for S schedules. They are not licensed ASME text. Verify against the current edition of ASME B36.10 before use.

The flange note on the page reads: Interim data from Texas Flange ASME B16.5 class charts and bolt-and-stud chart, not licensed ASME text. Verify against the current edition of ASME B16.5 before use.

The elbow allowance is 1.5 times the NPS. It is not an ASME B16.9 dimension. These interim figures will be replaced by licensed ASME data when it is available.

Limitations/disclaimer

The disclaimer on the tool: this is a geometric planning estimate, not a final engineering or structural design. Support loads, structural steel, thermal movement, fireproofing, access and maintenance requirements, and governing project standards are not fully checked. Valve and instrument geometry is only included when an explicit envelope is supplied.

• The schedule only selects the outside diameter table. The wall is not used.
• The local clearance is 50 mm on every line.
• Flange spacing uses the ASME B16.5 weld neck flange outside diameter only. Other flange types and B16.47 sizes are not read.
• The tier spacing minimum uses the largest line on each tier and an elbow of 1.5 times the NPS.
• One tier spacing applies to all tiers.
• The page holds 150 lines.
• Projects are kept in the browser only. Save project is not open yet.

Use the tool

Calculate now: Pipe Rack Designer

Related tools

• Line spacing calculator for the centre-to-centre spacing of two lines. Read the line spacing companion article.
• Rack and process spans for the span between rack bents. Read the rack and process spans companion article.
• Pipe by schedule for the outside diameter, wall, and weight of each line. Read the pipe by schedule companion article.
• Flange datasheet for the flange outside diameter behind a flange class. Read the flange datasheet companion article.
• Support details for the shoe under each line. Read the support details companion article.