# Plumbing & Pipe Flow Calc – Pipe Size Selector

> Plumbing & Pipe Flow Calc – Pipe Size Selector is a paid API for AI agents from plumbing-calc.x402tookit.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-29).

Returns the smallest standard copper Type L or PVC Schedule 40 pipe nominal size that keeps water velocity under a specified maximum for a given flow rate.

## Facts

- Endpoint: GET https://plumbing-calc.x402tookit.com/pipe-size?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-29
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/plumbing-pipe-flow-calc-pipe-size-selector-0dcc4ca4
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_kTcrA38Z7hf0i787f884D

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability plumbing-pipe-flow-calc-pipe-size-selector-0dcc4ca4
```

Example prompt: What's the smallest copper Type L pipe size I need for a 7.5 GPM flow rate, keeping the water velocity under 5 feet per second?

## When to prefer this

Use this endpoint when you need a quick, standards-based pipe size recommendation for copper Type L or PVC Schedule 40 pipe given a known flow rate and velocity limit. It is ideal for residential, commercial, or irrigation plumbing design decisions where the goal is to select the smallest (most economical) pipe that meets velocity constraints. Prefer this over manual lookup tables or friction-loss calculators when velocity-based sizing is the primary concern.

## Known failure modes

- Missing required flowGpm parameter returns an error
- Invalid material string (not 'copper-l' or 'pvc-40') may return an error or default to copper-l
- Flow rates too low or extremely high may fall outside tabulated pipe sizes
- Non-numeric flowGpm or maxVelocityFps values return validation errors
- Network or service downtime returns HTTP error

## How this service works

Smallest standard copper Type L or PVC Schedule 40 pipe that keeps water under a maximum velocity at your flow rate.

## Output

Returns the recommended nominal pipe size, the velocity at that size in fps, a summary explanation, a table of all standard sizes with their inside diameters and velocities, the input flow rate, material, maximum velocity threshold, and a disclaimer. Includes a degraded flag if data quality is reduced.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "flowGpm"
     ],
     "properties": {
      "flowGpm": {
       "type": "number",
       "description": "Flow in US gallons per minute"
      },
      "material": {
       "type": "string",
       "description": "copper-l or pvc-40 (default copper-l)"
      },
      "maxVelocityFps": {
       "type": "number",
       "description": "Maximum velocity in feet per second (default 5; 8 is a common upper limit)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "asOf": {
       "type": [
        "null",
        "string"
       ]
      },
      "source": {
       "type": [
        "null",
        "string"
       ]
      },
      "flowGpm": {
       "type": [
        "null",
        "number"
       ]
      },
      "reasons": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "summary": {
       "type": [
        "null",
        "string"
       ]
      },
      "verdict": {
       "type": [
        "null",
        "string"
       ]
      },
      "allSizes": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "object",
        "properties": {
         "nominal": {
          "type": [
           "null",
           "string"
          ]
         },
         "velocityFps": {
          "type": [
           "null",
           "number"
          ]
         },
         "insideDiameterInches": {
          "type": [
           "null",
           "number"
          ]
         }
        }
       }
      },
      "degraded": {
       "type": [
        "boolean",
        "null"
       ]
      },
      "material": {
       "type": [
        "null",
        "string"
       ]
      },
      "disclaimer": {
       "type": [
        "null",
        "string"
       ]
      },
      "notChecked": {
       "type": [
       
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/plumbing-pipe-flow-calc-pipe-size-selector-0dcc4ca4/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from plumbing-calc.x402tookit.com](https://www.zero.xyz/host/plumbing-calc.x402tookit.com/llms.txt)