What is the relationship between STD/XS and Schedule 40/80?

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.

How does stainless Schedule 40S differ from carbon Schedule 40?

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.

What does the hero and W_tot include?

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.

Which diameter for velocity vs pressure design?

Use ID for velocity and ΔP (v = Q / A, A = π ID²/4). Use OD for B31.3 thickness design and insulation sizing.

Pipe Schedule & Dimension Calculator

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 · W_tot = W_m · L · n

Catalog: W_m ≈ 0.0246615 · t · (OD − t) (steel screening)

ASME B36.10M / B36.19M pipe schedule lookup (this app)

Hero t (wall)ID OD − 2tW_tot W_m × L × nB36.19M 5S / 10S / 40S / 80S

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.

Wall Under-Tolerance (typical ASTM)−12.5% of nominal t

Pressure design uses minimum wall (≈ 0.875 × t_nom). This calculator returns nominal catalog t and ID — not under-tolerance walls.

STD / XS vs Sch 40 / Sch 80NPS ≤ 10 / ≤ 8 equivalent

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).

B36.19M Stainless (S)5S / 10S / 40S / 80S

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.

MTO Mass ScopePlain-end W_tot only

W_tot excludes flanges, fittings, contents, and coatings. Water-filled rack loads need a separate calculation.

Quick Reference Lookup Table

ASME B36.10M — matches pipeSchedule.json (this app) Sch 40 / Sch 80
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 VerificationShow

Step-by-Step Worked Example: NPS 4 Sch 40 — Match the Calculator Default

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.

Nominal Size:NPS 4 (DN 100)Schedule:Schedule 40 (STD equivalent at this size)Length L:6 m (single-random screening)Quantity n:1 pieceStandard:ASME B36.10M (carbon / alloy row)

1

Read OD and wall t from the app table

NPS 4 Sch 40: OD = 114.3 mm, t = 6.02 mm.

Result:OD = 114.3 mm, t = 6.02 mm

Hero displays wall thickness t = 6.02 mm.

2

Confirm inside diameter ID

Formula: ID = OD - 2t

ID = 114.3 − 2 × 6.02 = 102.26 mm (stored row value).

Result:ID = 102.26 mm

Use ID for hydraulic velocity and pressure-drop tools.

3

Read unit mass W_m

Catalog W_m = 16.07 kg/m for NPS 4 Sch 40 in pipeSchedule.json.

Result:W_m = 16.07 kg/m

Plain-end screening mass per metre.

4

Compute total MTO mass W_tot

W_{t o t} = W_{m} \cdot L \cdot n

W_tot = 16.07 kg/m × 6 m × 1 = 96.42 kg.

Result:W_tot = 96.42 kg

Matches the calculator total for the default inputs.

5

Optional: double quantity

W_{t o t} = W_{m} \cdot L \cdot n

With n = 2: W_tot = 16.07 × 6 × 2 = 192.84 kg.

Result:W_tot = 192.84 kg (n = 2)

Same L, doubled piece count.

Conclusion: Default app case NPS 4 Sch 40: OD 114.3 mm, t 6.02 mm, ID 102.26 mm, W_m 16.07 kg/m, W_tot 96.42 kg for L = 6 m and n = 1. Carry the same NPS/schedule into thickness, velocity, and ΔP tools.

5. Frequently Asked Questions & Technical References

Show

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.