Suction Specific Speed Calculator
N_ss — the cavitation-aggressiveness number reliability engineers screen pumps with.
The famous Amoco study tied high-N_ss pumps to failures when run away from BEP. Use double-suction impellers to halve the per-eye flow.
Formula
Suction Specific Speed Calculator is a free suction specific speed for pump engineers, plumbers and plant designers — instant, accurate and 100% client-side, with the governing formula and reference shown next to the result so the number can be defended, not just quoted.
About Suction Specific Speed Calculator
N_ss — the cavitation-aggressiveness number reliability engineers screen pumps with. The calculation implements N_ss = N·√Q_BEP / NPSHr^0.75 (ANSI/HI 9.6.1; Lobanoff & Ross, Centrifugal Pumps). The famous Amoco study tied high-N_ss pumps to failures when run away from BEP. Use double-suction impellers to halve the per-eye flow.
How to use Suction Specific Speed Calculator
- 1Enter Speed in rpm.
- 2Enter BEP flow (per eye) in m³/h.
- 3Enter NPSHr at BEP in m.
- 4Read Suction specific speed instantly — no submit button needed.
- 5Need US units? Flip the SI/Imperial toggle and every field converts.
Why use Suction Specific Speed Calculator?
- ✓Implements the standard formula — N_ss = N·√Q_BEP / NPSHr^0.75
- ✓Reference cited on-page: ANSI/HI 9.6.1; Lobanoff & Ross, Centrifugal Pumps
- ✓One-click SI ⇄ Imperial toggle — values convert in place, physics stays in SI
- ✓Built-in engineering verdict flags out-of-range results instantly
- ✓Runs entirely in your browser — nothing uploaded, free forever
Frequently asked questions
What formula does the Suction Specific Speed Calculator use?+
It computes N_ss = N·√Q_BEP / NPSHr^0.75, per ANSI/HI 9.6.1; Lobanoff & Ross, Centrifugal Pumps. The formula is displayed under the result.
What should I keep in mind when using this calculator?+
The famous Amoco study tied high-N_ss pumps to failures when run away from BEP. Use double-suction impellers to halve the per-eye flow.
Can I use this for pump selection?+
Use it to establish the duty (flow, head, NPSH, power) and then pick a pump whose curve passes through that point near best efficiency. The tool gives you the engineering numbers a supplier will ask for.
Is the Suction Specific Speed Calculator free to use?+
Yes — completely free, no sign-up, no limits. It runs client-side in your browser, so inputs stay private and results are instant even on slow connections.
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