Hazen-Williams pipe head loss API

Computes water head loss hf = 10.67·L·Q^1.852/(C^1.852·D^4.8704) (SI Hazen-Williams), returning head loss, hydraulic gradient, and pressure drop for a given roughness coefficient C. Answers 'What is the head loss in a water main?', 'What pressure drop does Hazen-Williams predict?'.

Price$0.06per request

MethodPOST

Route/v1/engineering/hazen-williams

StatusLive

MIME typeapplication/json

Rate limit120/minute

Cache0s public

engineeringthermofluidsfluidshazen-williamswater-distributionhead-losspipe-flowhydraulics

API URLhttps://x402.hexl.dev/v1/engineering/hazen-williams

Integration docs

Example request

{
  "flowRateM3s": 0.05,
  "diameterM": 0.2,
  "lengthM": 500,
  "roughnessCoefficient": 130
}

Example response

{
  "flowRateM3s": 0.05,
  "diameterM": 0.2,
  "lengthM": 500,
  "roughnessCoefficient": 130,
  "headLossM": 6.410137,
  "hydraulicGradientMperM": 0.01282027,
  "pressureDropPa": 62736.2433,
  "pressureDropKPa": 62.736243,
  "formula": "hf = 10.67*L*Q^1.852 / (C^1.852 * D^4.8704)  (SI)",
  "interpretation": "Empirical for water near room temperature; C ~140 (smooth PVC) to ~100 (old cast iron)."
}

Input schema

{
  "type": "object",
  "required": [
    "flowRateM3s",
    "diameterM",
    "lengthM",
    "roughnessCoefficient"
  ],
  "properties": {
    "flowRateM3s": {
      "type": "number",
      "description": "volumetric flow rate Q (m^3/s)",
      "examples": [
        0.05
      ]
    },
    "diameterM": {
      "type": "number",
      "description": "pipe inner diameter (m)"
    },
    "lengthM": {
      "type": "number",
      "description": "pipe length (m)"
    },
    "roughnessCoefficient": {
      "type": "number",
      "description": "Hazen-Williams C (140 PVC, 100 old cast iron)",
      "examples": [
        130
      ]
    },
    "densityKgM3": {
      "type": "number",
      "description": "density (kg/m^3); default 998"
    }
  }
}

Output schema

{
  "type": "object",
  "additionalProperties": true
}