Math & Numbers
Compute the available Net Positive Suction Head (NPSH_a) of a pump and compare it against the required NPSH (NPSH_r) from the pump curve. Head-balance form: NPSH_a = (p_surface_abs - p_vapor) / (ρ·g) + H_static - h_friction. Surface and vapor pressures are absolute; H_static is positive for flooded suction, negative for suction lift. Returns margin (NPSH_a - NPSH_r), ratio (NPSH_a/NPSH_r) and a classification: safe, marginal (margin < 0.5 m), or cavitation likely. If NPSH_r = 0, only NPSH_a is reported. Pressure in Pa/kPa/bar/atm/psi, length in m/ft, density in kg/m³/g/cm³/lb/ft³.
Call this tool from your code in three languages.
curl -X POST 'https://api.elysiatools.com/en/api/tools/pump-npsh-calculator' \
-H 'Content-Type: application/json' \
-d '{"surfacePressure":1,"pressureUnit":"atm","vaporPressure":2.34,"vaporPressureUnit":"kPa","staticHead":2,"staticHeadUnit":"m","frictionLoss":0.5,"frictionUnit":"m","density":1000,"densityUnit":"kg/m3","gravity":9.81,"npshRequired":3,"npshUnit":"m","decimalPlaces":4}'Send a POST request with your inputs as JSON. File parameters require a separate upload first.
POST https://api.elysiatools.com/en/api/tools/pump-npsh-calculator| Name | Type | Required | Description |
|---|---|---|---|
| surfacePressure | number | Yes | Absolute pressure at the liquid surface (p_surface). Enter in the selected Pressure Unit. |
| pressureUnit | select | No | — |
| vaporPressure | number | Yes | Absolute vapor pressure of the liquid at pumping temperature (p_vapor). Enter in the selected Vapor Pressure Unit. |
| vaporPressureUnit | select | No | — |
| staticHead | number | Yes | Elevation of liquid surface above pump centerline (H_static). Positive if liquid level is above the pump (flooded suction), negative for suction lift. Enter in the selected Static Head Unit. |
| staticHeadUnit | select | No | — |
| frictionLoss | number | No | Suction-line friction head loss (h_friction), already computed. Enter in the selected Friction Loss Unit. |
| frictionUnit | select | No | — |
| density | number | No | Liquid density (ρ). Enter in the selected Density Unit. |
| densityUnit | select | No | — |
| gravity | number | No | Gravitational acceleration g in m/s². |
| npshRequired | number | No | The pump's required NPSH (NPSH_r) from its curve. Enter in the selected NPSH Unit. If 0, the cavitation comparison is skipped and only NPSH_a is reported. |
| npshUnit | select | No | — |
| decimalPlaces | number | No | — |
JSON result
{
"key": {...},
"metadata": {
"key": "value"
},
"error": "Error message (optional)",
"message": "Notification message (optional)"
}Add this tool to your Model Context Protocol server so AI agents can list and call it.
Add this block to your MCP client configuration:
{
"mcpServers": {
"elysiatools-pump-npsh-calculator": {
"name": "pump-npsh-calculator",
"description": "Compute the available Net Positive Suction Head (NPSH_a) of a pump and compare it against the required NPSH (NPSH_r) from the pump curve. Head-balance form: NPSH_a = (p_surface_abs - p_vapor) / (ρ·g) + H_static - h_friction. Surface and vapor pressures are absolute; H_static is positive for flooded suction, negative for suction lift. Returns margin (NPSH_a - NPSH_r), ratio (NPSH_a/NPSH_r) and a classification: safe, marginal (margin < 0.5 m), or cavitation likely. If NPSH_r = 0, only NPSH_a is reported. Pressure in Pa/kPa/bar/atm/psi, length in m/ft, density in kg/m³/g/cm³/lb/ft³.",
"baseUrl": "https://api.elysiatools.com/mcp/sse?toolId=pump-npsh-calculator",
"command": "",
"args": [],
"env": {},
"isActive": true,
"type": "sse"
}
}
}After connecting to the SSE endpoint, list the exposed tools:
{
"jsonrpc": "2.0",
"id": 1,
"method": "tools/list"
}Invoke the tool by its id, passing arguments built from its parameters:
{
"jsonrpc": "2.0",
"id": 2,
"method": "tools/call",
"params": {
"name": "pump-npsh-calculator",
"arguments": {
"surfacePressure": 1,
"pressureUnit": "atm",
"vaporPressure": 2.34,
"vaporPressureUnit": "kPa",
"staticHead": 2,
"staticHeadUnit": "m",
"frictionLoss": 0.5,
"frictionUnit": "m",
"density": 1000,
"densityUnit": "kg/m3",
"gravity": 9.81,
"npshRequired": 3,
"npshUnit": "m",
"decimalPlaces": 4
}
}
}Questions or issues? Contact [email protected]