Why is 4 inch pipe 114.3 mm OD instead of 101.6 mm?

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.

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 for 10 Inch Schedule 40

Parameter	Value
Nominal pipe size (NPS)	10"
Schedule	Sch 40
Outside diameter (OD)	273.05 mm (10.750 in)
Wall thickness (t)	9.27 mm
Inside diameter (ID)	254.51 mm

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)

Sch 160 · NPS 6 t = 18.26 mmID 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) — including Schedule 160 thick-wall rows. 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. Example: NPS 6 Sch 160 → t = 18.26 mm, W_m ≈ 67.56 kg/m (SpecRoute 6-inch-sch-160).

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. Tolerances & Schedule Equivalence (This App)

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.

Schedule 160 (thick wall)NPS 6 → t = 18.26 mm

Sch 160 is thicker than Sch 80 / XS on common sizes. NPS 6 Sch 160: OD 168.28 mm, ID 131.76 mm, W_m ≈ 67.56 kg/m — SpecRoute 6-inch-sch-160. Not the same tag as XXS.

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 Schedule 160 (e.g. NPS 6 → t 18.26 mm), XXS, STD, and B36.19M S schedules. Unit toggle converts OD / t / ID columns.

3. Material Classes & Code Notes

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. How to look up pipe schedule dimensions

1
Select NPS
Use the isometric pipe size (not OD).
2
Select schedule
Sch 40 / STD and Sch 80 / XS are the usual carbon pair; pick S schedules for stainless.
3
Read t, OD, ID, W_m
Hero is wall t. Use ID for flow tools; OD for insulation / B31.3 inputs.
4
Optional MTO (1.2)
Set L and n to get W_tot = W_m × L × n, then export or carry NPS/Sch downstream.

6. Frequently Asked Questions & Technical References

Show

Schedule 160 is a thick ASME B36.10M wall class. Example FEK row NPS 6 Sch 160: OD 168.28 mm, t 18.26 mm, ID 131.76 mm, W_m ≈ 67.56 kg/m. Open SpecRoute /6-inch-sch-160. Sch 160 is not the same tag as XXS.

Pipe Schedule & Dimension

Indexable specification URLs

10 Inch Schedule 40 specification summary

1. Core Formula & Variable Definitions

2. Tolerances & Schedule Equivalence (This App)

Quick Reference Lookup Table

3. Material Classes & Code Notes

Code Applicability & Safety Boundaries

4. Step-by-Step Worked Example

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

Read OD and wall t from the app table

Confirm inside diameter ID

Read unit mass W_m

Compute total MTO mass W_tot

Optional: double quantity

5. How to look up pipe schedule dimensions

6. Frequently Asked Questions & Technical References

Pipe Schedule & Dimension

Indexable specification URLs

10 Inch Schedule 40 specification summary

1. Core Formula & Variable Definitions

2. Tolerances & Schedule Equivalence (This App)

Quick Reference Lookup Table

3. Material Classes & Code Notes

Code Applicability & Safety Boundaries

4. Step-by-Step Worked Example

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

Read OD and wall t from the app table

Confirm inside diameter ID

Read unit mass W_m

Compute total MTO mass W_tot

Optional: double quantity

5. How to look up pipe schedule dimensions

6. Frequently Asked Questions & Technical References

What is Schedule 160 pipe?

Why is 4 inch pipe 114.3 mm OD instead of 101.6 mm?

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

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

What does the hero and W_tot include?

Which diameter for velocity vs pressure design?