FieldEngineersKitEngineering Reference & ASME Code Basis
1. Core Formula & Variable Definitions
ASME B36.10M (Welded and Seamless Wrought Steel Pipe) · ASME B36.19M (Stainless Steel Pipe) · ISO 6708 (DN Designation) · ASTM A53 / A106 / A312 (material specs — not dimensional source for this lookup)
ID = OD − 2t · Wtot = Wm · L · n
Catalog: Wm ≈ 0.0246615 · t · (OD − t) (steel screening)
ASME B36.10M / B36.19M pipe schedule lookup (this app)
This calculator looks up OD, t, ID, and unit mass W_m from the app pipeSchedule table (B36.10M carbon/alloy; B36.19M stainless S schedules). Hero is nominal wall thickness t. Optional MTO inputs L and n give W_tot = W_m × L × n (plain-end screening mass). NPS is dimensionless: for NPS ≤ 12, OD exceeds the nominal inch size; from NPS 14 upward OD equals the nominal inch. STD ≈ Sch 40 through NPS 10; XS ≈ Sch 80 through NPS 8 — above those sizes weight-class walls diverge.
- NPS / DN (Nominal Size) — Dimensionless size tag (NPS inch designation; DN per ISO 6708).
- OD (Outside Diameter) — Standardized outside diameter from B36.10M / B36.19M (mm or in).
- t (Nominal Wall Thickness) — Hero output — catalog wall for the selected schedule (mm or in).
- ID (Inside Diameter) — Bore for flow: ID = OD − 2t (stored in the lookup row).
- W_m (Unit Linear Mass) — Plain-end mass per unit length (kg/m or lb/ft).
- W_tot (Total Mass (MTO)) — W_m × L × n for the entered length and piece count.
2. Allowances, Tolerances & Standards
Dimensions and W_m are screening lookups. Mill OD / wall under-tolerance and exact PO walls must still follow ASTM / project specs.
Pressure design uses minimum wall (≈ 0.875 × t_nom). This calculator returns nominal catalog t and ID — not under-tolerance walls.
STD = Sch 40 for NPS ≤ 10; XS = Sch 80 for NPS ≤ 8. Above those sizes walls diverge (e.g. NPS 12 STD = 9.53 mm, Sch 40 = 10.31 mm).
Stainless schedules follow B36.19M. For NPS ≤ 12, Sch 40S usually matches Sch 40; from NPS 14, Sch 40S often stays 9.53 mm while carbon Sch 40 increases.
W_tot excludes flanges, fittings, contents, and coatings. Water-filled rack loads need a separate calculation.
Quick Reference Lookup Table
| NPS | OD (mm) | Sch 40 t (mm) | Sch 40 ID (mm) | Sch 80 t (mm) |
|---|---|---|---|---|
| 2" | 60.33 | 3.91 | 52.51 | 5.54 |
| 4" | 114.3 | 6.02 | 102.26 | 8.56 |
| 6" | 168.28 | 7.11 | 154.06 | 10.97 |
| 8" | 219.1 | 8.18 | 202.74 | 12.7 |
| 10" | 273.05 | 9.27 | 254.51 | 15.09 |
| 12" | 323.85 | 10.31 | 303.23 | 17.48 |
Values match data/piping/pipeSchedule.json. Live lookup also covers additional schedules (10, 160, XXS, STD where listed) and B36.19M S schedules. Unit toggle converts OD / t / ID columns.
3. Material & Code Limitations
Schedule chooses geometry only. Allowable stress, MAWP, and metallurgy follow the piping code and ASTM grade — outside this dimension engine.
| Material Group | Temperature Range | Allowable Stress / Limit | Engineering Notes |
|---|---|---|---|
| Carbon Steel (ASTM A106 / A53) | Per B31.3 / material listing | Density screening ≈ 7,850 kg/m³ | Default industrial choice. Sch 40/STD for general service; Sch 80/XS for higher pressure or threaded ends as required by code. |
| Stainless (ASTM A312) — B36.19M | Per B31.3 / material listing | Density ≈ 7,930–7,980 kg/m³ | Use S schedules in the app (10S / 40S / 80S). Confirm thin 10S support spacing on long spans. |
| STD vs Sch 40 Divergence | N/A | NPS ≥ 12 | Do not assume STD = Sch 40 above NPS 10. State schedule or exact wall on the MTO. |
| Threaded Ends (B31.3 guidance) | N/A | Often Sch 80 for small NPS | Male CS threaded connections commonly need heavier walls on small sizes — confirm project / B31.3 rules; this tool does not enforce threading rules. |
Code Applicability & Safety Boundaries
- Calculator scope: B36.10M / B36.19M OD–t–ID–W_m lookup and optional W_tot = W_m × L × n. It does not size pressure design thickness (use the B31.3 thickness calculator).
- Use ID for velocity / ΔP; use OD for insulation and B31.3 design thickness inputs.
- W_tot is plain-end screening mass only — not water-filled rack load.
4. Step-by-Step Worked Example
Field VerificationShowHide
Reproduce the app default path: NPS 4 Schedule 40, L = 6 m, n = 1. Read OD, t, ID, W_m from pipeSchedule.json and compute W_tot.
Read OD and wall t from the app table
Hero displays wall thickness t = 6.02 mm.
Confirm inside diameter ID
Use ID for hydraulic velocity and pressure-drop tools.
Read unit mass W_m
Plain-end screening mass per metre.
Compute total MTO mass W_tot
Matches the calculator total for the default inputs.
Optional: double quantity
Same L, doubled piece count.
5. Frequently Asked Questions & Technical References
ShowHide
NPS is a dimensionless designator. For NPS ≤ 12, OD is larger than the nominal inch size (NPS 4 = 114.3 mm OD). From NPS 14 upward, OD equals the nominal inch size.
STD = Sch 40 for NPS ≤ 10 and XS = Sch 80 for NPS ≤ 8. Above those sizes they diverge (e.g. NPS 12 STD = 9.53 mm vs Sch 40 = 10.31 mm). State schedule or exact wall on the PO.
Sch 40 is B36.10M; Sch 40S is B36.19M. For NPS ≤ 12 walls usually match; from NPS 14, Sch 40S often stays 9.53 mm while carbon Sch 40 increases.
Hero is nominal wall t. W_tot = W_m × L × n is plain-end screening mass only — not water-filled rack load, flanges, or fittings.
Use ID for velocity and ΔP (v = Q / A, A = π ID²/4). Use OD for B31.3 thickness design and insulation sizing.