{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://www.calculatorx.com/schemas/physics.fluid.npsh/1.0.0/input.json",
  "title": "Net positive suction head — input",
  "type": "object",
  "additionalProperties": false,
  "properties": {
    "mode": {
      "type": "string",
      "enum": [
        "available",
        "margin"
      ],
      "description": "available (default, NPSHa) or margin (requires NPSHr). Not pump, orifice, weir, Manning, Darcy, or Q=Av."
    },
    "p_v": {
      "type": "number",
      "minimum": 0,
      "description": "Liquid vapor pressure in Pa absolute. User-supplied; this page is not a steam table."
    },
    "p_s": {
      "type": "number",
      "minimum": 0,
      "description": "Absolute pressure at the suction flange in Pa. Flange encoding. Do not send with tank z, hf, or p_atm."
    },
    "v_s": {
      "type": "number",
      "minimum": 0,
      "description": "Suction-flange velocity in m/s. Flange only. Default 0."
    },
    "z_s": {
      "type": "number",
      "description": "Elevation of the flange tap relative to the pump datum in m. Flange only. Default 0. May be negative."
    },
    "z": {
      "type": "number",
      "description": "Liquid-surface elevation above the pump datum in m. Open tank. Negative is a suction lift."
    },
    "hf": {
      "type": "number",
      "minimum": 0,
      "description": "Suction-line head loss in m. Open tank. Default 0. Input, not a Darcy solve."
    },
    "p_atm": {
      "type": "number",
      "exclusiveMinimum": 0,
      "description": "Absolute surface pressure in Pa. Open tank. Default 101325."
    },
    "NPSHr": {
      "type": "number",
      "minimum": 0,
      "description": "Required NPSH in m from the manufacturer. Optional in available; required in margin."
    },
    "rho": {
      "type": "number",
      "exclusiveMinimum": 0,
      "description": "Density in kg/m³. Default 1000."
    },
    "g": {
      "type": "number",
      "exclusiveMinimum": 0,
      "description": "Gravity in m/s². Default 9.80665."
    }
  },
  "required": [
    "p_v"
  ],
  "description": "NPSH available: open tank (p_atm−p_v)/ρg + z − hf, or suction flange (p_s−p_v)/ρg + v_s²/2g + z_s. Optional NPSHr margin. Not pump power, not orifice, not weir, not Q=Av, not Darcy. (calculation_version 1.0.0)"
}