How do Round percentages relate to ASME PCC-1?

This tool uses the same screening fractions as the FEK Bolt Torque calculator (30% / 60% / 100% / circular 100%). Owner appendices may specify bands such as 20–30% / 50–60% — follow the site procedure when it differs.

Where do I get the actual torque values?

Open the ASME PCC-1 Bolt Torque & Tensioning Calculator and carry over the same NPS / class when using the flange helper.

Flange Bolt Tightening Sequence — 56-Bolt Circular Pattern | FieldEngineersKit

Parameter	Value
Bolt count	56
Pattern	Circular
Sequence	1 → 2 → 3 → 4 → 5 → 6 → 7 → 8 → 9 → 10 → 11 → 12 → 13 → 14 → 15 → 16 → 17 → 18 → 19 → 20 → 21 → 22 → 23 → 24 → 25 → 26 → 27 → 28 → 29 → 30 → 31 → 32 → 33 → 34 → 35 → 36 → 37 → 38 → 39 → 40 → 41 → 42 → 43 → 44 → 45 → 46 → 47 → 48 → 49 → 50 → 51 → 52 → 53 → 54 → 55 → 56

1. Formula & conversion factors

ASME PCC-1 (Guidelines for Pressure Boundary Bolted Flange Joint Assembly) · ASME B16.5 / B16.47 (Flange bolting count)

Star sequence: groups of four — start → +N/2 → +N/4 → +3N/4 (bolt 1 at top, clockwise)

Round 1 = 0.30 T · Round 2 = 0.60 T · Round 3 = 1.00 T (star) · Round 4 = 1.00 T (circular)

ASME PCC-1 assembly guidance · ASME B16.5 / B16.47 bolt-count helper

8-bolt star 1→5→3→7→2→6→4→8Round 1–3 Star / crossRound 4 Circular 100%Bolt counts 4–64

This generator builds ASME PCC-1 style star/cross and circular bolt sequences for even counts from 4 to 64. Bolts are numbered clockwise with bolt 1 at the top of the flange. Optional NPS × class selection fills bolt count from the same B16.5 / B16.47 table used by the Bolt Torque calculator. Round fractions (30% / 60% / 100% / circular 100%) match FEK torque screening — confirm wrench targets against the project procedure.

N (Bolt count) — Number of studs on the bolt circle (even, 4–64). Optional flange preset fills N from B16.5 / B16.47.
Sequence (Tightening order) — Ordered list of bolt numbers for the selected pattern (star/cross or circular).
T (Target assembly torque) — Not computed here — use the Bolt Torque calculator for PCC-1 Round 1–4 wrench values.

2. Quick reference lookup table

Common star / cross sequences (bolt 1 at top, numbered clockwise)
Bolts (N)	Pattern name	Tightening sequence
4	Cross	1 → 3 → 2 → 4
8	Star	1 → 5 → 3 → 7 → 2 → 6 → 4 → 8
12	Star	1 → 7 → 4 → 10 → 2 → 8 → 5 → 11 → 3 → 9 → 6 → 12
16	Star	1 → 9 → 5 → 13 → 3 → 11 → 7 → 15 → 2 → 10 → 6 → 14 → 4 → 12 → 8 → 16
20	Star	1 → 11 → 6 → 16 → 2 → 12 → 7 → 17 → 3 → 13 → 8 → 18 → 4 → 14 → 9 → 19 → 5 → 15 → 10 → 20
24	Star	1 → 13 → 7 → 19 → 4 → 16 → 10 → 22 → 2 → 14 → 8 → 20 → 5 → 17 → 11 → 23 → 3 → 15 → 9 → 21 → 6 → 18 → 12 → 24

3. How to use this calculator

1
Select bolt count
Choose 4–64 bolts, or pick NPS × class to auto-fill from B16.5 / B16.47.
2
Choose pattern mode
Star/cross for Rounds 1–3; circular for the final check pass (or practice either).
3
Step through the diagram
Use Next / Prev or tap sequence chips to highlight each bolt in order.
4
Copy or export
Copy the arrow sequence text, or export PDF/CSV for the work pack.
5
Get torque values
Open the Bolt Torque calculator for Round 1–4 wrench targets at the same joint.

4. Engineering FAQ

Number bolts 1–8 clockwise from the top, then tighten 1 → 5 → 3 → 7 → 2 → 6 → 4 → 8. Finish with a circular 100% pass.