Equipment Nozzle Load Analysis — API 610 Annex F, NEMA SM-23, WRC-107 Screen
Five checks on one line: the per-component nozzle unity-ratio screen, the API 610 Annex F pump qualification, the NEMA SM-23 combined index, a WRC-107 / VIII-2 Part 5.5 shell screen that back-solves allowable loads, and the UCS-66 MDMT impact-exemption engine — with Ultimate-tier autofill of allowables from the embedded API 610 / 660 / 661 / 560 tables. Pro Plus tier; the method write-ups are free to read.
Content last reviewed · page regenerated 2026-09-03 at build.
What it does
The loads come from your flexibility analysis; the tool answers whether the equipment can take them, and it answers it the way each standard asks the question:
- Nozzle Load Check — the universal screen: six applied components against six allowables, a unity ratio per component, the governing component named, resultants FR and MR reported. The standard you pick — API 610, 560, 660, 661, 650, 620, NEMA SM-23, or a vendor datasheet — is a report label; the arithmetic is the same honest ratio.
- API 610 Annex F — the pump-specific qualification path: equations F.1–F.5 resolving suction and discharge loads to the pump center for horizontal machines, and the F.6–F.11 principal-stress path for vertical in-line pumps, where the per-component screen becomes advisory because Annex F itself permits exceeding it. Table 5 base allowables are your inputs; Annex F use requires purchaser approval, and the card says so.
- NEMA SM-23 / API 617 — the classic combined index: 3Fr + Mr against a coefficient times the equivalent nozzle diameter, De = (16 + NPS)/3 above NPS 8, with the coefficient editable rather than hard-coded, and a standing reminder that the per-component check still applies.
- Shell Nozzle Loads (WRC-107 / VIII-2 5.5) — from your chart coefficients, the card back-solves the allowable radial force, moments, shear and torsion left after pressure eats its share of the stress budget, then checks an applied load set through the VIII-2 Part 5.5 category ratios: Pm ≤ Sm, PL ≤ 1.5Sm, PL+Pb ≤ 1.5Sm. Cylindrical shells, with the nozzle-axis convention stated on the card.
- UCS-66 MDMT / impact exemption — the VIII-1 decision path: embedded 2025-edition Table UCS-66 with interpolation, the Figure UCS-66.1 coincident-ratio reduction, the (b)(3) blanket exemption at ratio ≤ 0.35, the (d) thin-material exemption, and the UCS-68.2(a) PWHT credit — verdict plus a basis string naming every clause applied.
Add to report captures the runs — the nozzle check with its per-component ratio table, the shell screen with its allowables and applied-check tables — into the Report Manager as a titleblocked, printable package with .pcp project files.
The preset picker: allowables without re-typing (Ultimate)
On Pro Plus, every allowable is hand-entered from your copy of the standard. Ultimate adds an autofill picker for the allowable load set — never the applied loads — from four embedded API tables:
| Standard | Table | Selection |
|---|---|---|
| API 610 13th Ed. (2026) | Tables 5a / 5b | table → nozzle orientation → NPS/DN, SI rows converted on apply |
| API 660 9th Ed. (R2025) | Table 2 | size → B16.5 flange class |
| API 661 7th Ed. (R2024) | Table 4 | size — with the §7.1.10 header-aggregate notes carried as inline warnings |
| API 560 6th Ed. (2026) | Tables 7 / 9 | tubes or manifolds → size |
Every pick writes a citation naming the edition, table and row into the inputs, so the captured report shows where the allowables came from. API 650 and 620 tank nozzles, NEMA coefficients, vendor datasheets, and all WRC chart coefficients stay user-supplied, and the tool's own text says so.
Where it sits next to FEA
Everything on this line is a screen — the standards' own pass/fail arithmetic, computed exactly and cited, not a stress field. The WRC card computes the thin-shell category assembly from coefficients you read off your WRC-107/297/537 charts; the copyrighted curves themselves are never embedded. That has a clean division of labor with PiperFEA: run the screens here first, because a nozzle that passes API 610 Table 5 with margin rarely justifies a model; take the junction to FEA when the geometry is off the charts, the load combination is outside the categories, or the ratio is too close to unity to trust a screen. And when the screen fails honestly — a real overload, not a margin call — the fix is usually upstream in the piping: more flexibility, a better support scheme, which is flexibility-analysis territory, not finer stress analysis at the nozzle.
A typical run: loads in, verdict out
- 1 — Bring the loads. Six components per nozzle from the stress model, in the equipment standard's axis system — the tool uses absolute values, so axis-system mismatches are yours to catch, and the card says so.
- 2 — Pick the check the standard asks for. Pump: Annex F. Turbine or compressor: NEMA SM-23 plus the per-component screen. Exchanger, air cooler, fired heater: the unity-ratio check against the table allowables — autofilled on Ultimate, typed from your copy otherwise.
- 3 — Screen the shell if the equipment table doesn't govern. The WRC card turns chart coefficients into allowable loads and category ratios for the vessel wall itself.
- 4 — Close the MDMT question. If the nozzle check is part of a vessel job, the UCS-66 card answers whether impact testing is required at your design metal temperature, with the clause trail printed.
- 5 — Capture. Add to report files the ratio tables into the Report Manager; print to PDF or download HTML, save the .pcp.
Sixteen fixture cases lock the five engines in CI — several of them hand-derived worked cases published in the fixture files, including an Annex F case built to fail F.5 so the failure path is tested, not assumed.
What's free and what needs Pro Plus
The method pages are free to read — the nozzle load check calculator page documents the unity-ratio screen with a fixture-verified worked example. The live Equipment line is Pro Plus, and the table autofill is Ultimate:
- Free — $0: all 49 code calculators and every method write-up.
- Pro — $2.99/month or $29/year: report capture, Report Manager, .pcp files, batch runs, cited factor pickers.
- Pro Plus — $7.99/month or $79/year: PiperNOZ (this tool — all five cards, manual allowable entry), PiperFLG bolted-flange analysis, PiperHGR spring sizing, the UCS-66 MDMT tool. Monthly plan starts with 30 days free.
- Ultimate — $14.99/month or $149/year: adds the API 610/660/661/560 preset autofill with cited picks, plus PiperFEA, PiperSTR and the PiperISO premium exports.
The full matrix and billing FAQ are at /pricing/.
Demo video
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PiperNOZ - Equipment Nozzle Load Check (API 610 / 560 / 660 / 661 & NEMA SM-23) (0:57) — The dedicated PiperNOZ demo: six load components checked as unity ratios against user-supplied allowables, the governing component named, resultants reported, and the PASS/FAIL verdict framed against API 610/560/660/661 and NEMA SM-23 practice. Watch on YouTube.
Open the tool
Open PiperNOZ — it loads in this tab on a Pro Plus account. If you only need the ratio arithmetic explained first, the free method page walks a fixture-verified example; the tool is for the week where the pump vendor, the exchanger datasheet and the stress model all arrive at once.
FAQ
What does each of the five cards actually check?
The Nozzle Load Check is the universal screen: six applied components against six allowables, a unity ratio each, the governing component named, resultants reported. The API 610 Annex F card runs the pump-specific qualification — equations F.1 through F.5 resolving suction and discharge loads to the pump center for horizontal machines, and the F.6 through F.11 principal-stress path for vertical in-line pumps, where the per-component screen becomes advisory because Annex F itself permits exceeding it. The NEMA SM-23 card computes the classic combined index, 3Fr + Mr against a coefficient times equivalent nozzle diameter, with the coefficient editable rather than hard-coded. The Shell Nozzle card turns your WRC-chart coefficients into allowable loads and VIII-2 Part 5.5 category checks. And the UCS-66 card answers a different question entirely: whether the material needs impact testing at your minimum design metal temperature.
Which allowable-load tables are embedded, and which stay user-supplied?
Four tables are embedded, and they autofill allowables only — never applied loads: API 610 Tables 5a and 5b for pumps, by table, nozzle orientation and size, with SI rows converted on apply; API 660 Table 2 for shell-and-tube exchangers by size and flange class; API 661 Table 4 for air-cooler headers, carrying the §7.1.10 aggregate-load notes as inline warnings; and API 560 Tables 7 and 9 for fired-heater tubes and manifolds. Every pick writes a citation naming the edition, table and row, so the report shows where the numbers came from. Everything else — API 650 and 620 tank nozzles, NEMA SM-23 coefficients, vendor datasheets, and every WRC chart coefficient — stays permanently user-supplied; the tool's own text says so. The four-table autofill is the Ultimate add-on — the Pro Plus calculators take the same values typed by hand.
Does it compute WRC-107 local stresses from my geometry?
It computes the category assembly, not the chart lookup — and the distinction is the data firewall. You read the dimensionless membrane and bending coefficients off your own WRC-107, 297 or 537 charts for your β and γ, and the card does the thin-shell arithmetic the bulletins leave to you: the pressure membrane term, allowable radial force and moments back-solved from the remaining stress budget, shear and torsion limits, and the VIII-2 Part 5.5 category ratios — general membrane against Sm, local membrane against 1.5·Sm, membrane plus bending against 1.5·Sm — for a cylindrical shell with the nozzle axis convention stated on the card. The curves themselves are copyrighted and are never embedded. When the screen is not enough — a geometry off the charts, a load combination the categories do not cover, or a result too close to unity to trust — PiperFEA models the junction with actual finite elements.
How does the UCS-66 MDMT card decide whether impact testing is required?
It walks the same decision path a vessel engineer walks in VIII-1, and prints the paragraph it used. The base exemption temperature comes from the embedded 2025-edition Table UCS-66 — ninety-three thickness rows, curves A through D, interpolated between tabulated thicknesses. If you supply a coincident stress ratio, the Figure UCS-66.1 reduction applies, read by you from the figure because the 2025 edition ships no tabular companion; at a ratio of 0.35 or less the UCS-66(b)(3) blanket exemption takes over. Material 0.10 inch and thinner exempts under UCS-66(d), bolting is excluded from the reductions, and a P-No. 1 material post-weld heat treated when the code did not require it earns the UCS-68.2(a) 30°F credit. The verdict is a boolean — impact test required or not — plus a basis string naming every clause applied, so the reviewer checks the reasoning, not just the answer.
How is this different from the nozzle-load-check calculator page?
The calculator page documents one engine — the per-component unity-ratio screen — with its method, limitations and a fixture-verified worked example free to read, and that page remains the right reference for what the ratio check is. The tool is the workspace around it: the same screen plus the API 610 Annex F pump qualification, the NEMA SM-23 combined index, the WRC-family shell screen with allowable back-solving, and the UCS-66 impact-exemption engine, all on one line with report capture into a titleblocked package. Sixteen fixture cases lock the five engines, several of them hand-derived worked cases published in the fixture files themselves. The honest framing: if you need one ratio check once, read the free page and do it by hand; if equipment nozzle qualification is a recurring part of your week, the tool is the difference between re-deriving context every time and opening a workspace that kept it.