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API 610 Nozzle Load Calculator

Check applied pump nozzle forces and moments against API 610 (12th ed.) Table 5 allowables by flange size and orientation

🔩 API 610 Nozzle Load Check
Pick the flange size and nozzle orientation, then enter your applied piping loads. The tool looks up the API 610 (12th ed.) Table 5 per-nozzle allowable and checks each force and moment — plus the resultant FR and MR — against it. Each Table 5 value is a ± allowable (NOTE 2).

Nozzle

Only the force allowables differ by orientation; moments are the same for all three.
Nominal flange size of the nozzle (NPS in USC, DN in SI).

Applied Forces

force
force
force
Enter the magnitude of each applied force; sign is not needed (allowable is ±).

Applied Moments

moment
moment
moment
Forces in lbf / N, moments in ft·lbf / N·m per the unit system selected.

What This Checks

Per-Axis Forces:
|FX|, |FY|, |FZ| each against the API 610 Table 5 allowable for the chosen flange size and nozzle orientation.
Per-Axis Moments:
|MX|, |MY|, |MZ| against Table 5 — moment limits are identical for top, side and end nozzles.
Resultants:
FR = √(FX²+FY²+FZ²) ≤ FR-allow and MR = √(MX²+MY²+MZ²) ≤ MR-allow, with a per-axis and resultant pass/fail summary.

📘 Table 5 Explained

API 610 (12th ed.) Table 5 tabulates the maximum nozzle loads a compliant pump must accept:

Organized by size & orientation
  • Allowables grow with flange size (NPS ≤2 → 16 / DN ≤50 → 400)
  • Force limits differ for top, side and end nozzles
  • Moment limits (MX, MY, MZ, MR) are the same for all orientations
Each value is ± (NOTE 2)
  • The tabulated number is the magnitude of an allowable range −val to +val
  • Enter the magnitude of each applied load; direction does not change the limit
Resultant checks
  • FR = √(FX²+FY²+FZ²) ≤ FR-allow
  • MR = √(MX²+MY²+MZ²) ≤ MR-allow

Single-Nozzle Screen vs Annex F

This tool performs the per-nozzle Table 5 screen only. It is fast, conservative, and ideal for early piping layout and stress-check kickoff.

Full qualification = API 610 Annex F. Annex F evaluates the combined loads on both nozzles plus pump and baseplate displacements, and can conditionally permit loads up to the Table 5 values when those displacements are checked and shown acceptable.

Exceeding Table 5 here does not automatically disqualify the pump — it flags that an Annex F assessment is required.

Standards Reference

  • API 610 (12th ed.) Table 5: Allowable nozzle forces & moments by flange size and orientation (each value is ± per NOTE 2)
  • API 610 Annex F: Full multi-nozzle qualification, incl. the conditional 2× allowance when displacements are evaluated
  • API 610 §6.2: Pump nozzle and casing construction

Frequently Asked Questions

What are API 610 nozzle loads?

API 610 nozzle loads are the external forces and moments that connected piping imposes on a pump's suction and discharge nozzles. API 610 (12th ed.) Table 5 lists the allowable force (Fx, Fy, Fz) and moment (Mx, My, Mz) for each flange size and nozzle orientation (top, side, end). Per Table 5 NOTE 2, each tabulated value is a ± allowable, so the load may act in either direction up to that magnitude.

Why do pump nozzle loads matter?

Excessive piping loads distort the pump casing, which springs the shaft out of alignment and overloads the seal and bearings. The result is short seal life, premature bearing failure, internal rubbing, and lost efficiency. Limiting nozzle loads to API 610 Table 5 keeps casing distortion and coupling misalignment within tolerances the pump was qualified for.

What about API 610 Annex F and the 2× rule?

Table 5 is a per-nozzle screen. Full multi-nozzle qualification is performed per API 610 Annex F, which evaluates the combined loads on both nozzles plus pump and baseplate displacements. Annex F can conditionally permit loads up to twice the Table 5 values when those displacements are checked and shown acceptable. This calculator only performs the single-nozzle Table 5 screen — exceeding it does not automatically disqualify the pump, but it flags that an Annex F assessment is required.