FieldEngineersKit LogoFieldEngineersKit
Docs
Clean zone

ASME B16.34 Valve Wall Thickness & Pressure Rating Calculator

ASME B16.34-2020 §6.1 · Table 3 · Table 2 · Mandatory Appendix VI
Loading calculator…

← All indexable specifications for this calculator· Current spec: NPS 6 · Class 900 · A105 · 400 °F

NPS 6 · Class 900 · A105 · 400 °F valve wall & P-T rating summary

Live inputs drive this summary. Adjust values in the calculator to recalculate; primary selections update the clean share URL for indexing and handoff.

ParameterValue
Nominal pipe size (NPS)6"
Pressure classClass 900

Engineering Reference & ASME Code Basis

1. Core Formula & Variable Definitions

ASME B16.34-2020 Valves — Flanged, Threaded, and Welding End · ASME B16.34 §6.1 Minimum Wall Thickness · ASME B16.34 Table 3 Valve Body Minimum Wall Thickness · ASME B16.34 Table 2 Pressure-Temperature Ratings (Standard Class) · ASME B16.34 Mandatory Appendix VI Basis for Minimum Wall Thickness Equations

tm = 1.5 · [Pc · d / (2S − 1.2 Pc)] + A

pmax = fB16.34(Class, Material Group, T)  ·  phydro = 1.5 · pamb,38°C

ASME B16.34-2020 Mandatory Appendix VI (S = 7000 psi, A = 0.10 in / 2.54 mm) · Table 3 discrete check · Table 2 Standard Class P-T

S 7000 psi (48.3 MPa)A 0.10 in (2.54 mm)Default duty NPS 4 · Class 300 · 5.91 mmHydro 1.5 × ambient rating

Wall thickness uses the Appendix VI US-customary equation with class designation pressure P_c (psi) and fixed S = 7000 psi. Table 3 values in this tool are the same equation evaluated at discrete inside diameters. Standard Class P-T for Groups 1.1 and 2.2 matches the ASME B16.5 Table 2 Phase-1 extract. Special Class and Section 8 NDE rules are out of scope.

  • t_m (Minimum body wall thickness) — Required valve body wall from Appendix VI / Table 3 for the selected class and inside diameter d.
  • d (Inside / port diameter) — Valve flow-passage inside diameter used in Appendix VI (mm or in).
  • P_c (Class designation pressure) — Class rating reference pressure: 150, 300, 600, 900, 1500, or 2500 psi.
  • S (Appendix VI stress factor) — Fixed 7000 psi basis in Mandatory Appendix VI wall equations.
  • p_max (Allowable pressure at temperature) — Standard Class P-T rating from ASME B16.34 Table 2 for the material group and design temperature.
  • p_hydro (Hydrostatic shell test pressure) — 1.5 × ambient (38 °C) Standard Class rating for factory shell test screening.

2. Screening Assumptions

Standard Class body wall and P-T screen for metal valves. Neck detailing, casting/forging tolerance, and Special Class rules are out of scope.

Wall basisAppendix VI + Table 3 discrete check

Governing t_m is the greater of the closed-form Appendix VI result and the interpolated Table 3 discrete grid (same equation basis).

Default dutyNPS 4 · Class 300 · d = 102 mm · 200 °C · 35 bar · Group 1.1

Hero t_m = 5.91 mm; p_max = 43.8 bar (Pass). Hydro shell screen = 1.5 × 51.1 bar = 76.7 bar.

P-T Phase-1 groups1.1 and 2.2 tabulated; 1.2 proxy; 1.9 unavailable

Groups 1.1 / 2.2 use the published Standard Class extract (aligned with B16.5 Table 2). Group 1.2 (WCC) uses Group 1.1 as a conservative proxy. Group 1.9 (WC6) wall still screens; P-T is marked unavailable.

Out of scopeSpecial Class · Section 8 NDE · soft-seat trim

Forged high-pressure valves with additional NDE and Special Class ratings require the full ASME B16.34 Section 8 path and OEM charts.

Quick Reference Lookup Table

Appendix VI / Table 3 wall check — Class 300 inside diameter vs t_m (metric)
Inside d (mm)t_m (mm)P_c (psi)Basis
504.19300Appendix VI
805.18300Appendix VI
1005.84300Appendix VI
1025.91300Default duty
1507.49300Appendix VI
2009.14300Appendix VI
25010.79300Appendix VI

Values are Appendix VI equation results (S = 7000 psi, A = 0.10 in) rounded for field screening. Confirm published ASME B16.34 Table 3 for purchase documents.

3. Material Groups & Temperature Limits

ASME B16.34 Table 1A material groups used for Standard Class P-T screening in this Phase-1 extract.

Material GroupTemperature RangeAllowable Stress / LimitEngineering Notes
Group 1.1 — A105 / A216 WCB−29 to 538 °C (Class-dependent)Standard Class Table 2-1.1Default carbon-steel forged / cast body group.
Group 1.2 — A216 WCCSame band as Group 1.1 (proxy)Phase-1 uses Group 1.1 curveConservative screening proxy only — confirm published Table 2-1.2 for purchase.
Group 2.2 — A351 CF8M / 316−29 to 538 °C (Class-dependent)Standard Class Table 2-2.2 (Phase-1: Class 150–600)Austenitic stainless cast / forged bodies in Phase-1 extract.
Group 1.9 — A217 WC6P-T Phase-1 unavailableWall screen only (Appendix VI)Load full ASME B16.34 Table 2-1.9 before accepting Cr-Mo P-T duty.

Code Applicability & Safety Boundaries

  • Standard Class only — Special Class ratings are not tabulated here
  • Confirm OEM casting drawings for neck thickness beyond pure t_m

4. Step-by-Step Worked Example

Field VerificationShow

Worked example — NPS 4 · Class 300 · WCB · 200 °C

Standard Class carbon-steel gate/globe body, NPS 4, Class 300, port inside diameter 102 mm, design 35 bar at 200 °C, material Group 1.1 (A105 / WCB).

NPS / Class:4 / 300d:102 mmT / P:200 °C / 35 barMaterial:Group 1.1 A105 / WCB
1

Appendix VI wall

t_m = 1.5 · [300 · (102/25.4) / (2·7000 − 1.2·300)] + 0.10 in → mm
Result:t_m = 5.91 mm (Table 3 check agrees)
2

P-T rating at 200 °C

Interpolate Standard Class Group 1.1 · Class 300 table
Result:p_max = 43.8 bar
3

Duty check & hydro

P_design ≤ p_max; p_hydro = 1.5 · p_amb(38 °C)
Result:35 ≤ 43.8 → Pass; p_hydro = 76.7 bar
Conclusion: Required minimum body wall is t_m = 5.91 mm. Allowable pressure at 200 °C is 43.8 bar (Pass vs 35 bar design). Factory shell hydro screen is 76.7 bar. Confirm OEM casting drawing for neck and casting allowance beyond this pure t_m.

5. How to screen ASME B16.34 valve body wall and P-T rating

  1. 1

    Select NPS, class, and inside diameter

    Enter the valve NPS, Standard Class (150–2500), and the port / inside diameter d in mm or inches.

  2. 2

    Choose material group and duty

    Pick the B16.34 Table 1A group and enter design temperature and working pressure in the active unit system.

  3. 3

    Read t_m and p_max

    Hero shows governing t_m. Badges show p_max at temperature and Pass / Overpressure vs design pressure.

  4. 4

    Export or continue

    Export CSV/PDF for the duty pack, or carry NPS/class/temperature to pipe wall, flange dimension, or valve Cv tools.

6. Frequently Asked Questions & Technical References

Show

A field screen of Standard Class valve body minimum wall t_m from Appendix VI / Table 3, plus Table 2 P-T allowable pressure and a 1.5× ambient hydro shell test estimate.

ADVERTISEMENT

320×50 In-feed Banner